首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献，搜索用时 46 毫秒
1.
BACKGROUND: Although definitive diagnosis of hypoadrenocorticism usually is made by an adrenocorticotrophic hormone (ACTH) stimulation test using 250 microg/dog of synthetic ACTH (cosyntropin/tetracosactrin), increased costs have prompted a search for less-expensive diagnostic methods. HYPOTHESIS: A low-dose ACTH stimulation test (5 microg/kg) will distinguish between dogs with nonadrenal illness and hypoadrenocorticism. Additionally, administration of cosyntropin will not affect the results of another ACTH stimulation test performed 24 hours later. ANIMALS: Eight healthy adult dogs and 29 hospitalized dogs with suspected hypoadrenocorticism. METHODS: In this prospective study, each healthy dog received 4 ACTH stimulation tests. Dogs received either 5 microg/kg or 250 microg/dog of cosyntropin on day 1 and the alternate dose on day 2. The opposite dosing sequence was used after a 2-week washout period (days 15 and 16). Dogs with suspected Addison's disease received 2 ACTH stimulation tests, 24 hours apart, using either a dose of 5 microg/kg cosyntropin or 250 microg/dog on the 1st day and the alternate dose on the 2nd day. RESULTS: In healthy dogs, poststimulation cortisol concentrations on days 2 and 16 and days 1 and 15 were equivalent (90% confidence interval [CI]: 86.7-101.2%). In dogs with suspected Addison's disease, mean (+/-SD) cortisol responses to ACTH in the 5 microg/kg dose (16.2+/-7.7 microg/dL) and 250 microg/dog dose (15.9+/-6.3 microg/dL) were statistically equivalent (90% CI: 91.2-105.4%). CONCLUSIONS AND CLINICAL IMPORTANCE: Low-dose ACTH stimulation testing distinguishes between dogs with nonadrenal illness and hypoadrenocorticism. Additionally, the administration of 2 ACTH stimulation tests on consecutive days does not affect results of the second test.  相似文献   

2.
OBJECTIVE: To compare the effects of 2 doses of cosyntropin (5 microg/kg vs 250 microg, IV) on serum concentrations of cortisol, sex hormones of adrenal origin, and adrenocortical steroid intermediates and determine the optimal sample collection time after adrenal stimulation with cosyntropin. ANIMALS: 10 healthy, privately owned, neutered dogs. PROCEDURE:Dogs were randomly assigned to initially receive cosyntropin at 5 microg/kg or as a total dose of 250 microg, IV. Dogs received the alternate dose 1 to 2 weeks later. Serum was obtained from blood samples collected before (0 minutes) and 30, 60, 90, and 120 minutes after cosyntropin administration. RESULTS:Maximum stimulation of cortisol, androstenedione, progesterone, and 17-hydroxyprogesterone production was achieved at 60 minutes following IV administration of cosyntropin at 5 microg/kg or as a total dose of 250 microg. Serum estradiol concentration did not increase in response to either cosyntropin dose. For all hormones, no significant difference in serum hormone concentrations was found among sample collection times of 0, 30, 60, and 90 minutes when comparing the 2 doses of cosyntropin. CONCLUSIONS AND CLINICAL RELEVANCE: Cosyntropin, when administered at 5 microg/kg, IV, effectively stimulated maximum production of cortisol, sex hormones of adrenal origin, and adrenocortical steroid intermediates at 1 hour after administration.  相似文献   

3.
BACKGROUND: Cosyntropin (adrenocorticotropic hormone [ACTH]) stimulation tests are used to evaluate adrenal function. Low-dose ACTH stimulation tests are the most accurate method for diagnosing relative adrenal insufficiency in critically ill humans but have not been evaluated in foals. HYPOTHESIS: Peak serum cortisol concentrations in healthy foals will not be significantly different after intravenous administration of 1, 10, 100, and 250 microg of cosyntropin. ANIMALS: 14 healthy neonatal foals, 3-4 days of age. METHODS: A randomized cross-over model was used in which cosyntropin (1, 10, 100, or 250 microg) was administered intravenously on days 3 and 4 of life. Blood samples were collected before and 30, 60, 90, 120, and 150 minutes after administration of cosyntropin for determination of serum cortisol concentration. RESULTS: Serum cortisol concentrations did not significantly increase after administration of 1 microg of cosyntropin. Cortisol concentration peaked 30 minutes after administration of 10 microg of cosyntropin and 90 minutes after 100 and 250 microg of cosyntropin. There was no relationship between cosyntropin dose and serum cortisol concentration at 30 minutes. Compared with the 10-microg dose, 100 and 250 microg of cosyntropin induced significantly greater cortisol concentrations at 90 minutes, at which point the 10-microg cosyntropin-dose cortisol values were indistinguishable from baseline. There was no significant difference in the area under the cortisol concentration curve between the 100- and 250-microg doses. No effect of day of testing or foal weight on peak cortisol concentration was detected. CONCLUSIONS AND CLINICAL IMPORTANCE: The results of this study suggest that 10- and 100-microg doses of cosyntropin would be appropriate for evaluating adrenal function in neonatal foals.  相似文献   

4.
OBJECTIVE: To compare adrenal gland stimulation achieved following administration of cosyntropin (5 microg/kg [2.3 microg/lb]) IM versus IV in healthy dogs and dogs with hyperadrenocorticism. DESIGN: Clinical trial. Animals-9 healthy dogs and 9 dogs with hyperadrenocorticism. PROCEDURES: In both groups, ACTH stimulation was performed twice. Healthy dogs were randomly assigned to receive cosyntropin IM or IV first, but all dogs with hyperadrenocorticism received cosyntropin IV first. In healthy dogs, serum cortisol concentration was measured before (baseline) and 30, 60, 90, and 120 minutes after cosyntropin administration. In dogs with hyperadrenocorticism, serum cortisol concentration was measured before and 60 minutes after cosyntropin administration. RESULTS: In the healthy dogs, serum cortisol concentration increased significantly after administration of cosyntropin, regardless of route of administration, and serum cortisol concentrations after IM administration were not significantly different from concentrations after IV administration. For both routes of administration, serum cortisol concentration peaked 60 or 90 minutes after cosyntropin administration. In dogs with hyperadrenocorticism, serum cortisol concentration was significantly increased 60 minutes after cosyntropin administration, compared with baseline concentration, and concentrations after IM administration were not significantly different from concentrations after IV administration. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that in healthy dogs and dogs with hyperadrenocorticism, administration of cosyntropin at a dose of 5 microg/kg, IV or IM, resulted in equivalent adrenal gland stimulation.  相似文献   

5.
We evaluated the effect of ovine corticotropin-releasing hormone (CRH) on plasma immunoreactive (IR) concentrations of ACTH, alpha-melanocyte-stimulating hormone, and cortisol in 8 dogs with naturally acquired adrenocortical insufficiency. Of the 7 dogs with primary adrenal insufficiency, 6 had markedly high basal plasma IR-ACTH concentrations and exaggerated ACTH responses to CRH administration, whereas 1 dog that was receiving replacement doses of prednisone at the time of testing had normal basal IR-ACTH concentrations and a nearly normal response to CRH. In contrast, the 1 dog with secondary adrenocortical insufficiency had undetectable basal plasma IR-ACTH concentrations, which failed to increase after administration of CRH. Basal plasma alpha-melanocyte-stimulating hormone concentrations in the dogs with adrenal insufficiency were within normal range and were unaffected by CRH administration. In all 8 dogs with adrenal insufficiency, plasma cortisol concentrations were low and did not increase after administration of CRH. Therefore, stimulation with CRH produced 2 patterns of plasma IR-ACTH response when administered to dogs with naturally acquired adrenal insufficiency. Dogs with primary adrenal insufficiency had high basal plasma IR-ACTH concentrations and exaggerated responses to CRH, whereas the dog with secondary adrenal insufficiency had undetectable basal plasma concentrations of IR-ACTH that did not increase after stimulation with CRH.  相似文献   

6.
OBJECTIVE: To determine the lowest of 5 doses of cosyntropin (1.0, 0.5, 0.1, 0.05, or 0.01 microg/kg) administered IV that stimulates maximal cortisol secretion in clinically normal dogs. ANIMALS: 10 clinically normal dogs. PROCEDURES: 5 dose-response experiments were performed in each of the dogs. Each dog received 5 doses of cosyntropin (1.0, 0.5, 0.1, 0.05, and 0.01 microg/kg) IV in random order (2-week interval between each dose). Serum samples for determination of cortisol concentrations were obtained before (baseline) and at 10, 20, 30, 40, 50, 60, 120, and 240 minutes after cosyntropin administration. RESULTS: Compared with baseline values, mean serum cortisol concentration in the study dogs increased significantly after administration of each of the 5 cosyntropin doses. Mean peak serum cortisol concentration was significantly lower after administration of 0.01, 0.05, and 0.1 microg of cosyntropin/kg, compared with findings after administration of 0.5 and 1.0 microg of cosyntropin/kg. After administration of 0.5 and 1.0 microg of cosyntropin/kg, mean peak serum cortisol concentration did not differ significantly; higher doses of cosyntropin resulted in more sustained increases in serum cortisol concentration, and peak response developed after a longer interval. CONCLUSIONS AND CLINICAL RELEVANCE: Administration of cosyntropin IV at a dose of 0.5 microg/kg induced maximal cortisol secretion in healthy dogs. Serum cortisol concentration was reliably increased in all dogs after the administration of each of the 5 doses of cosyntropin. These data should be useful in subsequent studies to evaluate the hypothalamic-pituitary-adrenal axis in healthy and critically ill dogs.  相似文献   

7.
OBJECTIVE: To determine whether basal serum or plasma cortisol concentration can be used as a screening test to rule out hypoadrenocorticism in dogs. DESIGN: Retrospective case-control study. ANIMALS: 110 dogs with nonadrenal gland illnesses and 13 dogs with hypoadrenocorticism. PROCEDURES: Sensitivity and specificity of basal serum or plasma cortisol concentrations of either 2 microg/dL that are not receiving corticosteroids, mitotane, or ketoconazole are highly unlikely to have hypoadrenocorticism. However, if the basal cortisol concentration is 相似文献   

8.
OBJECTIVE: To determine whether low doses of synthetic ACTH could induce a maximal cortisol response in clinically normal dogs and to compare a low-dose ACTH stimulation protocol to a standard high-dose ACTH stimulation protocol in dogs with hyperadrenocorticism. DESIGN: Cohort study. ANIMALS: 6 clinically normal dogs and 7 dogs with hyperadrenocorticism. PROCEDURE: Each clinically normal dog was given 1 of 3 doses of cosyntropin (1, 5, or 10 micrograms/kg [0.45, 2.3, or 4.5 micrograms/lb] of body weight, i.v.) in random order at 2-week intervals. Samples for determination of plasma cortisol and ACTH concentrations were obtained before and 30, 60, 90, and 120 minutes after ACTH administration. Each dog with hyperadrenocorticism was given 2 doses of cosyntropin (5 micrograms/kg or 250 micrograms/dog) in random order at 2-week intervals. In these dogs, samples for determination of plasma cortisol concentrations were obtained before and 60 minutes after ACTH administration. RESULTS: In the clinically normal dogs, peak cortisol concentration and area under the plasma cortisol response curve did not differ significantly among the 3 doses. However, mean plasma cortisol concentration in dogs given 1 microgram/kg peaked at 60 minutes, whereas dogs given doses of 5 or 10 micrograms/kg had peak cortisol values at 90 minutes. In dogs with hyperadrenocorticism, significant differences were not detected between cortisol concentrations after administration of the low or high dose of cosyntropin. CLINICAL IMPLICATIONS: Administration of cosyntropin at a rate of 5 micrograms/kg resulted in maximal stimulation of the adrenal cortex in clinically normal dogs and dogs with hyperadrenocorticism.  相似文献   

9.
BACKGROUND: Dogs with single congenital portosystemic shunts (CPSS) often develop postoperative hypoglycemia and prolonged anesthetic recovery. These abnormalities could be attributable to inadequate adrenal response. However, adequacy of adrenal response after CPSS surgery is unexplored. HYPOTHESIS: Dogs with CPSS have inadequate postoperative adrenal response. ANIMALS: Eight nonoperated, 8 ovariohysterectomy (OHE), and 16 CPSS dogs. METHODS: Consecutive day ACTH stimulation tests were performed on nonoperated healthy dogs, healthy dogs before and after OHE, and CPSS dogs before and after surgery. Adequate response was defined as >50% or >30 ng/mL increase in cortisol after ACTH administration. Blood glucose (BG) was monitored before and after surgery. Prolonged anesthetic recovery and refractory hypoglycemia episodes were recorded. RESULTS: Results of consecutive day ACTH stimulation tests did not vary in normal dogs. Results of preoperative ACTH stimulation tests of CPSS and OHE dogs were not significantly different. Dogs with CPSS had higher postoperative baseline cortisol concentrations (median, 329 ng/mL) than OHE dogs (median, 153 ng/mL). Postoperative cortisol increase after ACTH in CPSS was < or =50% in 10/16 and < or =30 ng/mL in 6/16. After surgery, BG was < or =60 mg/dL in 7/16 CPSS dogs. Cortisol concentrations were not correlated with BG. Two CPSS dogs had refractory hypoglycemia and 4 had delayed recovery; all improved with dexamethasone administration (0.1-0.2 mg/kg/IV). CONCLUSIONS AND CLINICAL IMPORTANCE: Contrary to previous reports, baseline cortisol concentrations in CPSS and healthy dogs are similar. Many CPSS dogs have postoperative hypercortisolemia. Response to ACTH does not correlate with postoperative hypoglycemia or prolonged anesthetic recovery.  相似文献   

10.
Background: Relative cortisol insufficiency occurs in septic foals and impacts survival. Serum free (biologically available) cortisol concentration might be a better indicator of physiologic cortisol status than serum total cortisol concentration in foals. Hypotheses: In septic foals, (1) low free cortisol concentration correlates with disease severity and survival and (2) predicts disease severity and outcome better than total cortisol concentration. Animals: Fifty‐one septic foals; 11 healthy foals; 6 healthy horses. Methods: In this prospective clinical study, foals meeting criteria for sepsis at admission were enrolled. University‐owned animals served as healthy controls. Basal and cosyntropin‐stimulated total cortisol concentration and percent free cortisol (% free cortisol) were determined by chemiluminescent immunoassay and ultrafiltration/ligand‐binding methods, respectively. Group data were compared by ANOVA, Mann‐Whitney U‐tests, and receiver operator characteristic curves. Significance was set at P < .05. Results: Basal % free cortisol was highest in healthy foals at birth (58±8% mean±SD), and was higher (P≤.004) in healthy foals of all ages (33±6 to 58±8%) than in adult horses (7±3%). Cosyntropin‐stimulated total and free cortisol concentrations were lower (P≤.03) in foals with shock (total = 6.2±8.1 μg/dL; free = 3.5±4.8 μg/dL versus total = 10.8±6.0 μg/dL; free = 6.9±3.3 μg/dL in foals without shock) and in nonsurvivors (total = 3.8±6.9 μg/dL; free = 1.9±3.9 μg/dL versus total = 9.1±7.7 μg/dL; free = 5.5±4.4 μg/dL in survivors). Free cortisol was no better than total cortisol at predicting disease severity or outcome in septic foals. Conclusions and Clinical Importance: Serum free cortisol is impacted by age and illness in the horse. There is no advantage to measuring free over total cortisol in septic foals.  相似文献   

11.
OBJECTIVE: To evaluate pituitary-adrenal function in critically ill dogs with sepsis, severe trauma, and gastric dilatation-volvulus (GDV). DESIGN: Cohort study. ANIMALS: 31 ill dogs admitted to an intensive care unit (ICU) at Washington State University or the University of Pennsylvania; all dogs had acute critical illness for < 48 hours prior to admission. PROCEDURES: Baseline and ACTH-stimulated serum cortisol concentrations and baseline plasma ACTH concentrations were assayed for each dog within 24 hours after admission to the ICU. The change in cortisol concentrations (Delta-cortisol) was calculated for each dog. Morbidity and mortality data were recorded for each patient. RESULTS: Overall, 17 of 31 (55%) acutely critically ill dogs had at least 1 biochemical abnormality suggestive of adrenal gland or pituitary gland insufficiency. Only 1 (3%) dog had an exaggerated response to ACTH stimulation. Dogs with Delta-cortisol < or = 83 nmol/L were 5.7 times as likely to be receiving vasopressors as were dogs with Delta-cortisol > 83 nmol/L. No differences were detected among dogs with sepsis, severe trauma, or GDV with respect to mean baseline and ACTH-stimulated serum cortisol concentrations, Delta-cortisol, and baseline plasma ACTH concentrations. CONCLUSIONS AND CLINICAL RELEVANCE: Biochemical abnormalities of the hypothalamic-pituitary-adrenal axis indicative of adrenal gland or pituitary gland insufficiency were common in critically ill dogs, whereas exaggerated responses to ACTH administration were uncommon. Acutely ill dogs with Delta-cortisol < or = 83 nmol/L may be more likely to require vasopressors as part of the treatment plan.  相似文献   

12.
Background: Transient hypothalamic-pituitary-adrenal (HPA) axis dysfunction occurs frequently in critically ill humans and impacts survival. The prevalence and impact of HPA axis dysfunction in critically ill neonatal foals are not well characterized.
Hypotheses: (1) HPA axis dysfunction occurs in hospitalized neonatal foals, and is characterized by inappropriately low basal serum cortisol concentration or inadequate cortisol response to exogenous adrenocorticotropic hormone (ACTH); (2) hospitalized foals with HPA axis dysfunction have more severe disease and are less likely to survive than hospitalized foals with normal HPA axis function.
Animals: Seventy-two hospitalized foals and 23 healthy age-matched foals.
Methods: Basal ACTH and cortisol concentrations were measured and a paired low-dose (10 μg)/high-dose (100 μg) cosyntropin stimulation test was performed at admission in hospitalized foals. HPA axis dysfunction was defined as (1) an inappropriately low basal cortisol concentration or (2) an inadequate increase in cortisol concentration (delta cortisol) after administration of cosyntropin, with cut-off values for appropriate basal and delta cortisol concentrations determined from results obtained in healthy age-matched foals.
Results: Forty-six percent of hospitalized foals had an inappropriately low basal cortisol concentration and 52% had an inadequate delta cortisol concentration after administration of the 100 μg dose of cosyntropin. An inadequate delta cortisol response to the high (100 μg) dose of cosyntropin was significantly correlated with shock and multiple organ dysfunction syndrome in hospitalized foals, and with decreased survival in a subgroup of septic foals.
Conclusions and Clinical Importance: HPA axis dysfunction occurs frequently in hospitalized neonatal foals, and negatively impacts disease severity and survival.  相似文献   

13.
BACKGROUND: Sepsis is an important cause for neonatal foal mortality. The hypothalamic-pituitary-adrenal axis (HPAA) responses to sepsis are well documented in critically ill humans, but limited data exist in foals. The purpose of this study was to evaluate the HPAA response to sepsis in foals, and to associate these endocrine changes with survival. HYPOTHESIS: Blood concentrations of arginine vasopressin (AVP), adrenocorticotropin hormone (ACTH), and cortisol will be higher in septic foals as compared with sick nonseptic and healthy foals. The magnitude of increase in hormone concentration will be negatively associated with survival. ANIMALS: Fifty-one septic, 29 sick nonseptic, and 31 healthy foals of < or =7 days of age were included. METHODS: Blood was collected at admission for analysis. Foals with positive blood culture or sepsis score > or =14 were considered septic. Foals admitted with disease other than sepsis and healthy foals were used as controls. AVP, ACTH, and cortisol concentrations were measured using validated immunoassays. RESULTS: AVP, ACTH, and cortisol concentrations were increased in septic foals. Septic nonsurvivor foals (n = 26/51) had higher plasma ACTH and AVP concentrations than did survivors (n = 25/51). Some septic foals had normal or low cortisol concentrations despite increased ACTH, suggesting relative adrenal insufficiency. AVP, ACTH, and cortisol concentrations were higher in sick nonseptic foals compared with healthy foals. CONCLUSIONS AND CLINICAL IMPORTANCE: Increased plasma AVP and ACTH concentrations in septic foals were associated with mortality. Several septic foals had increased AVP : ACTH and ACTH : cortisol ratios, which indicates relative adenohypophyseal and adrenal insufficiency.  相似文献   

14.
This prospective, interventional, case-controlled study sought to determine the association between adrenocortical function and mortality in dogs with naturally occurring Babesia rossi babesiosis. Sixty-eight dogs with canine babesiosis were studied and fifteen normal dogs were used as controls. Blood samples were obtained from the jugular vein in each dog prior to treatment, at admission to hospital, for the measurement of basal plasma ACTH (adrenocorticotrophic hormone) and serum cortisol concentrations. Immediately thereafter, each dog was injected intravenously with 5 microg/kg of ACTH (tetracosactrin). A second blood sample was taken 1h later for serum ACTH-stimulated cortisol measurement and the resultant calculation of delta cortisol by subtracting basal from ACTH-stimulated cortisol. Diagnosis of babesiosis was confirmed by polymerase chain reaction (PCR) and reverse line blot (RLB). Three outcomes were defined: hospitalization with subsequent death (n=4); hospitalization followed by recovery (n=48); and treatment as an outpatient (n=16). Basal cortisol, but not ACTH-stimulated cortisol, was significantly higher in patients compared to control dogs. Basal- and ACTH-stimulated serum cortisol concentrations were significantly higher in the dogs that died, compared to hospitalized dogs that survived and compared to dogs treated as outpatients. There was no significant difference in delta cortisol concentrations or cortisol to ACTH ratios across outcome groups in dogs suffering from B. rossi babesiosis However, dogs with delta cortisol concentrations below 83 nmol/l had significantly higher cortisol to ACTH ratios compared to dogs with delta cortisol concentrations above 83 nmol/l. These findings of increased basal- and ACTH-stimulated cortisol and increased cortisol to ACTH ratios confirm the absence of adrenal insufficiency and concur with those in human malaria.  相似文献   

15.
Objective – To describe a case of hydrocortisone-responsive hypotension and critical illness-related corticosteroid insufficiency (CIRCI) in a dog with septic shock.
Case Summary – A dog with aspiration pneumonia developed septic shock with pressor-refractory hypotension. A standard ACTH stimulation test was performed that showed a blunted cortisol response consistent with CIRCI. Reversal of shock was achieved within 2 hours of hydrocortisone administration, and complete weaning from pressors was accomplished over the subsequent 8 hours. The patient recovered and was discharged from the hospital. An ACTH stimulation test performed 1 month after hospital discharge showed normal adrenal responsiveness consistent with resolution of CIRCI.
New or Unique Information Provided – This case is the first published report of hydrocortisone-responsive hypotension and transient CIRCI associated with naturally occurring septic shock in a dog.  相似文献   

16.
Effects of etomidate on adrenocortical function in canine surgical patients   总被引：1，自引：0，他引：1  
Adrenocortical function in canine surgical patients given etomidate at 1 of 2 dosages (1.5 mg/kg of body weight or 3 mg/kg, IV) was evaluated and compared with that of dogs given thiopental (12 mg/kg, IV). The adrenocortical function was evaluated by use of adrenocorticotropic hormone (ACTH) stimulation tests and determination of plasma cortisol concentrations at 0 minute (base line) and 60 minutes after ACTH administration. At 24 hours before administration of either drug (ie, induction of anesthesia), each dog had an increase in plasma cortisol concentration when given ACTH. The ACTH stimulation tests were repeated 2 hours after induction of anesthesia. Dogs given thiopental had base-line plasma cortisol concentrations greater than preinduction base-line values, but did not increase plasma cortisol in response to ACTH stimulation. Postinduction ACTH stimulation tests in dogs given etomidate at either dose indicated base-line and 60-minute plasma cortisol concentrations that were not different from preinduction base-line values. Therefore, adrenocortical function was suppressed 2 and 3 hours after the administration of etomidate in canine surgical patients.  相似文献   

17.
A combined dexamethasone suppression and cosyntropin (synthetic ACTH) stimulation test was developed in the dog so that information concerning pituitary gland (hypophysis) and adrenal gland competence could be provided in a single trial, during a short time span. Treatment of dogs with dexamethasone (0.1 mg/kg, IM) resulted in total suppression (below assay sensitivity or < 10 ng/ml) of plasma hydrocortisone (cortisol) at postinjection hour (PIH) 2 in 100% of the dogs, whereas suppression was inconsistent at PIH 1. Cosyntropin (0.5 U/kg, IV) administration to normal or dexamethasone-suppressed dogs increased plasma hydrocortisone concentration 3.5 to 4.5 times base-line values at PIH 1, which was the time of maximal effect. The combined test concept for adrenal gland function is valid, convenient (three sample collections; 3-hour period), and allows testing of adrenal gland response to dexamethasone suppression and ACTH stimulation in a single trial. The following test procedure for dogs is recommended: (i) collect base-line plasma sample (0900 hours) followed by injection of dexamethasone (0.1 mg/kg, IM); (ii) collect second plasma sample 2 hours after dexamethasone (to evaluate suppression of plasma hydrocortisone concentration) followed by the injection of cosyntropin (0.5 U/kg, IV); and (iii) collect a third plasma sample 1 hour later to evaluate plasma hydrocortisone concentration after cosyntropin stimulation.  相似文献   

18.
Plasma aldosterone concentrations were measured in response to adrenocorticotropic hormone (ACTH) gel administration in clinically normal dogs, in dogs with hypoadrenocorticism, and in dogs (with electrolyte abnormalities) that did not have hypoadrenocorticism. Baseline plasma aldosterone concentrations were determined from specimens obtained every 10 minutes for 3 hours from 2 dogs and every 30 minutes for 7.5 hours from 2 other dogs. During the evaluation period, plasma aldosterone concentrations varied by at least 50% in each dog. A randomized crossover design was used to compare changes in plasma aldosterone concentrations after administration of ACTH gel and physiologic NaCl solution. Dogs had significantly (P = 0.002) higher plasma aldosterone concentrations after administration of ACTH gel than after administration of NaCl solution. Plasma cortisol concentrations increased as expected after ACTH gel administration. Analysis of cortisol and aldosterone concentrations in the same specimens obtained at 7 sample collection times did not reveal significant linear correlation, and scatterplots did not indicate a nonlinear association. In addition, plasma aldosterone concentrations were determined in response to ACTH administration alone and to ACTH combined with a high dose of dexamethasone (0.1 mg/kg, IV). The plasma aldosterone response to ACTH alone was not significantly different from the response to ACTH combined with dexamethasone. For both tests, plasma aldosterone concentrations at 60 and 120 minutes after ACTH administration were significantly (P less than 0.0005 and P = 0.0001, respectively, increased, compared with base-line values. Six dogs with adrenocortical hypofunction, as determined by plasma cortisol concentrations before and after ACTH administration, had plasma aldosterone concentrations that were diminished or did not increase after ACTH administration.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   

19.
OBJECTIVE: To evaluate adrenal sex hormone concentrations in response to ACTH stimulation in healthy dogs, dogs with adrenal tumors, and dogs with pituitary-dependent hyperadrenocorticism (PDH). DESIGN: Prospective study. ANIMALS: 11 healthy control dogs, 9 dogs with adrenal-dependent hyperadrenocorticism (adenocarcinoma [ACA] or other tumor); 11 dogs with PDH, and 6 dogs with noncortisol-secreting adrenal tumors (ATs). PROCEDURE: Hyperadrenocorticism was diagnosed on the basis of clinical signs; physical examination findings; and results of ACTH stimulation test, low-dose dexamethasone suppression test, or both. Dogs with noncortisol-secreting ATs did not have hyperadrenocorticism but had ultrasonographic evidence of an AT. Concentrations of cortisol, androstenedione, estradiol, progesterone, testosterone, and 17-hydroxyprogesterone were measured before and 1 hour after i.m. administration of 0.25 mg of synthetic ACTH. RESULTS: All dogs with ACA, 10 dogs with PDH, and 4 dogs with ATs had 1 or more sex hormone concentrations greater than the reference range after ACTH stimulation. The absolute difference for progesterone, 17-hydroxyprogesterone, and testosterone concentrations (value obtained after ACTH administration minus value obtained before ACTH administration) was significantly greater for dogs with ACA, compared with the other 3 groups. The absolute difference for androstenedione was significantly greater for dogs with ACA, compared with dogs with AT and healthy control dogs. CONCLUSIONS AND CLINICAL RELEVANCE: Dogs with ACA secrete increased concentrations of adrenal sex hormones, compared with dogs with PDH, noncortisol-secreting ATs, and healthy dogs. Dogs with noncortisol-secreting ATs also have increased concentrations of sex hormones. There is great interdog variability in sex hormone concentrations in dogs with ACA after stimulation with ACTH.  相似文献   

20.
Cushing's disease caused by pituitary corticotroph adenoma in dogs is usually treated by medical treatment, and the efficacy of this treatment has been reported. However, controversy remains as to whether reduced negative feedback through the inhibition of cortisol secretion, similar to Nelson's syndrome, may appear as an adverse effect. The purpose of this study was to investigate the effect of reduced negative feedback through the inhibition of cortisol secretion by daily trilostane administration on the pituitary–adrenal axis in clinically normal dogs. Dogs were administered 5 mg/kg trilostane twice a day every day for 8 weeks (n = 8) or 16 weeks (n = 3). After the initiation of trilostane administration, plasma adrenocorticotropic hormone (ACTH) concentrations were increased remarkably. As assessed by magnetic resonance imaging (MRI) during administration, the pituitary became enlarged. After trilostane administration, the cytoplasmic areas of the pituitary corticotrophs were increased and the ratio of pituitary corticotrophs to all cells in the anterior lobe was greater in the trilostane-treated dogs than that in untreated animals. In addition, histological examinations revealed bilateral adrenal cortical hyperplasia. Using real-time PCR quantification, the expression of proopiomelanocortin (POMC) mRNA in the pituitary and ACTH receptor (ACTH-R) mRNA in the adrenal gland was greater in the dogs treated with trilostane than in untreated dogs. These results indicate that reduced negative feedback induced hyperfunction of the pituitary corticotrophs and pituitary enlargement in healthy dogs. These changes suggest that the inhibition of cortisol secretion by trilostane may increase the risk for accelerating the growth of corticotroph adenomas in dogs with Cushing's disease.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号