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1.
Four dogs with clinical evidence of hyperadrenocorticism were evaluated by use of x-ray-computed tomography (CT). Adrenal masses were identified accurately and localized. Unilateral adrenal masses were diagnosed accurately in dogs 1, 2, and 3 and were removed surgically via a paracostal retroperitoneal approach to the adrenal gland. Using CT and IV contrast medium, the adrenal mass in dog 3 also was accurately diagnosed as being highly vascular. The histopathologic diagnosis was adrenal adenoma in dogs 1, 2, and 3. In dog 4, the CT-roentgen diagnosis was asymmetric bilateral adrenal enlargement. Necropsy examination of dog 4 indicated moderate enlargement of the left adrenal gland and severe enlargement of the right adrenal gland. Results of microscopic examination indicated chronic inflammation of the left adrenal gland and adenocarcinoma of the right adrenal gland. Use of CT facilitated localization of adrenal masses and fulfilled the needs of a localizing technique. A unilateral mass can be removed surgically via a limited exposure, retroperitoneal incision on the affected side of the animal instead of removal via abdominal laparotomy, which is more invasive. Advantages of CT can reduce the needs of other imaging modalities for the localization of adrenal masses.  相似文献   

2.
Results of abdominal survey radiography and x-ray computed tomography (CT) were compared in 13 dogs with hyperadrenocorticism histologically attributed to adrenocortical tumors. X-ray computed tomography enabled accurate localization of the tumor in all 13 dogs. Apart from 2 poorly demarcated irregular-shaped and mineralized carcinomas, there were no differences between adenoma (n = 3) and carcinoma (n = 10) on CT images. In 1 dog, invasion of the caudal vena cava by the tumor was suggested on CT images and was confirmed during surgery. Suspicion of adhesions between tumors of the right adrenal gland and the caudal vena cava on the basis of CT images was confirmed during surgery in only 2 of 6 dogs. Survey radiography allowed accurate localization of the tumor in 7 dogs (4 on the right side and 3 on the left). In 6 of these dogs, the tumor was visible as a well-demarcated soft tissue mass and, in the other dog, as a poorly demarcated mineralized mass. The smallest tumor visualized on survey radiographs had a diameter of 20 mm on CT images. Six tumors with diameter less than or equal to 20 mm were not visualized on survey radiographs. In 1 of these dogs, a mineralized nodule was found in the left adrenal region, without evidence of a mass. In a considerable number of cases, survey radiography can provide presurgical localization of adrenocortical tumors in dogs with hyperadrenocorticism; CT is redundant in these instances. In the absence of positive radiographic findings, CT is valuable for localization of adrenocortical tumors.  相似文献   

3.
OBJECTIVE: To evaluate the effects of mitotane administration on the function and morphology of pituitary corticotrophs in clinically normal dogs. ANIMALS: 12 clinically normal adult Beagles. PROCEDURES: Dogs were randomly assigned to the control group or the mitotane treatment group. In mitotane treatment group dogs, mitotane was administered for 1 month. In both groups, ACTH stimulation testing and corticotrophin-releasing hormone (CRH) stimulation testing were performed. Magnetic resonance imaging (MRI) of the pituitary gland and brain was performed in mitotane treatment group dogs before and after administration of mitotane. After CRH stimulation testing and MRI, dogs were euthanatized and the pituitary gland and adrenal glands were excised for gross and histologic examination. RESULTS: ACTH concentrations in mitotane treatment group dogs were significantly higher than in the control group dogs following CRH stimulation. Magnetic resonance imaging revealed that pituitary glands were significantly larger in treatment group dogs after administration of mitotane, compared with before administration. On gross and histologic examinations, the adrenal cortex was markedly atrophied. Immunohistochemistry revealed hypertrophy of corticotrophs in pituitary glands of mitotane treatment group dogs. CONCLUSIONS AND CLINICAL RELEVANCE: These findings indicate that inhibition of the adrenal cortex by continuous administration of mitotane leads to functional amplification and morphologic enhancement of corticotrophs in clinically normal dogs. In instances of corticotroph adenoma, hypertrophy of individual corticotrophs induced by mitotane may greatly facilitate enlargement of the pituitary gland and increases in ACTH secretion.  相似文献   

4.
A 9-year-old female spayed Holland Lop rabbit (Oryctolagus cuniculus) presented with abnormal eyelid positioning on the right eye of 2 week duration. A full neurological examination revealed ptosis, enopthalmia, decreased palpebral reflex of the right eye. A pre and post contrast CT-study confirmed a large heterogeneously contrast-enhancing and partially peripherally mineralized parasellar pituitary mass. Stereotactic radiation was performed delivering 3 fractions of 8 Gy every other day (total dose 24 Gy) using volumetric-modulated arc therapy for the pituitary mass. A progressive decrease in size of the pituitary mass was observed on two follow-up CT-studies at six- and eighteen-months post-radiotherapy. The adrenal panels performed during follow-up visits suggested increased adrenal activity post-radiotherapy. No adverse effects of radiation therapy were noted at home or subsequent veterinary visits. CT imaging was a reliable modality for diagnosing and monitoringthe pituitary mass. Treatment with stereotactic radiotherapy resulted in a marked reduction in the pituitary mass volume with a long survival time and without adverse effects. Radiation therapy should be considered a treatment option in rabbits with pituitary tumors and the protocol used in this case could be used as a reference for future cases.  相似文献   

5.
This retrospective study was performed to investigate the diagnostic efficacy of the chemiluminometric ACTH-measurement to differentiate between pituitary and adrenal dependent hyperadrenocorticism (HAC) in dogs. 49 dogs with pituitary HAC, 10 dogs with adrenal HAC and 1 dog with a combination of both pathologies were included. Dogs with HAC like symptoms, where HAC had been ruled out, served as controls (n = 18). All dogs with adrenal HAC, as well as 9 dogs with pituitary HAC had an ACTH concentration below the detection limit of 2.2 pmol/l (10 pg/dl) plasma. Using 2.2 pmol/l as a cut-off the sensitivity and specificity to diagnose pituitary HAC was 0.82 (95 % CI 0.686 - 0.914) and 1 (95 % CI 0.692 - 1), respectively. With the help of the chemiluminometric assay, a correct classification was possible in 85 % of patients with HAC. As an ACTH-concentration below the detection limit was found in dogs with adrenal as well as pituitary HAC, additional discriminatory tests are necessary in these cases.  相似文献   

6.
Dynamic helical computed tomography (CT) of the pituitary gland can be used to image the three-dimensional shape and dimensions of abnormalities within the pituitary gland. The aim of this study was to develop a protocol for dynamic helical CT of the pituitary gland in healthy dogs as a future reference study for patients with pituitary disease. Dynamic helical series of nine scans of the pituitary gland during and following contrast medium injection were performed in six healthy dogs using the following protocols: a series with 1 mm collimation and a table feed per X-ray tube rotation of 2 mm (pitch of 2) in six dogs, a series with 2 mm collimation and pitch of 2 in three dogs, and a series with 1 mm collimation and pitch of 1 in three other dogs. Multiplanar reconstructions of the images were made using a reconstruction index of 0.5. Images of all series were assessed visually for enhancement of the arteries, the neurohypophysis, and the adenohypophysis. The enhancement pattern of the neurohypophysis was distinguished adequately from that of the adenohypophysis in five dogs that were scanned with 1 mm collimation and pitch of 2, but the difference was less discernable when the other protocols were used. The carotid artery, its trifurcation, and the arterial cerebral circle were best visualized in dorsal reconstructions. Dynamic helical CT of the pituitary gland in healthy dogs can be performed with 1 mm collimation and pitch of 2, and a scan length that includes the entire pituitary region. Using this protocol, with the specific scanner used, the neurohypophysis, the adenohypophysis, and the surrounding vascular structures are adequately visualized.  相似文献   

7.
Dynamic computed tomography (CT) of the pituitary gland was performed in 55 dogs with pituitary-dependent hyperadrenocorticism (PDH) that underwent transsphenoidal hypophysectomy. On routine contrast-enhanced CT images, microadenomas of the pituitary gland often are indistinguishable from nontumorous pituitary tissue because of isoattenuation. Dynamic CT may allow visualization of these adenomas. The changes in the contrast-enhancement pattern of the pituitary during dynamic CT in 55 dogs with PDH were correlated with surgical and histopathologic findings. In 36 dogs, dynamic CT identified distinct contrast enhancement of the neurohypophysis (pituitary flush). In 24 dogs, this pituitary flush was displaced, which indicated the presence of an adenoma. This observation was confirmed surgically and histopathologically in 18 of the 24 dogs. In 19 dogs, there was a diffusely abnormal contrast-enhancement pattern. CT findings agreed with surgical findings in 13 of these dogs and with histopathologic findings in all 19 dogs. It is concluded that a dynamic series of scans should be included in the CT protocol of the pituitary gland in dogs with PDH because it allows for identification of an adenoma or a diffusely abnormal pituitary gland.  相似文献   

8.
Spontaneous hyperadrenocorticism in dogs is known to be the result of excessive secretion of adrenocorticotropic hormone (ACTH) by the pituitary gland or excessive autonomous glucocorticoid secretion by an adrenocortical tumor. Here, we report on an 8-year-old German shepherd dog in which ACTH-dependent hyperadrenocorticism was a result of ectopic ACTH secretion and could be related to an abdominal neuroendocrine tumor. Hyperadrenocorticism was diagnosed on the basis of the history, clinical signs, and elevated urinary corticoid/creatinine ratios (UCCRs; 236 and 350 x 10(-6); reference range < 10 x 10(-6)). The UCCR remained elevated (226 x 10(-6)) after three oral doses of dexamethasone (0.1 mg/kg body weight) at 8-h intervals. Ultrasonography revealed two equivalently enlarged adrenal glands, consistent with adrenocortical hyperplasia. Plasma ACTH concentration was clearly elevated (159 and 188 ng/l; reference range 5-85 ng/l). Computed tomography (CT) revealed that the pituitary was not enlarged. These findings were interpreted as indicating dexamethasone-resistant pituitary-dependent hyperadrenocorticism. Transsphenoidal hypophysectomy was performed but within 2 weeks after surgery, there was exacerbation of the clinical signs of hyperadrenocorticism. Plasma ACTH concentration (281 ng/l) and UCCRs (1518 and 2176 x 10(-6)) were even higher than before surgery. Histological examination of the pituitary gland revealed no neoplasia. Stimulation of the pituitary with corticotropin-releasing hormone did not affect plasma ACTH and cortisol concentrations. Treatment with trilostane was started and restored normocorticism. CT of the pituitary fossa, 10 months after hypophysectomy, revealed an empty sella. Hence, it was presumed that there was ectopic secretion of ACTH. CT of the abdomen revealed a mass in the region of the pancreas and a few nodules in the liver. Partial pancreatectomy with adjacent lymph node extirpation was performed and the liver nodules were biopsied. Histological examination revealed a metastasized neuroendocrine tumor. Abdominal surgery was not curative and medical treatment with trilostane was continued. At 18 months after the abdominal surgery, the dog is still in good condition. In conclusion, the combination of (1) severe dexamethasone-resistant hyperadrenocorticism with elevated circulating ACTH levels, (2) definitive demonstration of the absence of pituitary neoplasia, and (3) an abdominal neuroendocrine tumor allowed the diagnosis of ectopic ACTH secretion.  相似文献   

9.
Diagnosis and surgical management of intra-abdominal or retroperitoneal hemorrhage in 4 dogs with rupture of an adrenal gland tumor were determined. All 4 dogs were lethargic and weak with pale mucous membranes on initial examination. Three dogs did not have any history of clinical signs of hyperadrenocorticism or pheochromocytoma prior to examination. In 3 of the dogs, a mass in the area of the adrenal gland was identified with ultrasonography prior to surgery. All dogs developed ventricular premature contractions before or during anesthesia. Three dogs survived adrenalectomy; 1 dog was euthanatized during surgery because of an inability to achieve adequate hemostasis. The remaining 3 dogs all survived more than 5 months after surgery; 1 was euthanatized 9 months after surgery because of rupture of a hepatic mass. On the basis of these results, we suggest that hemodynamic stabilization followed by adrenalectomy is the treatment of choice for dogs with nontraumatic rupture of an adrenal gland tumor and resulting life-threatening hemorrhage.  相似文献   

10.
OBJECTIVE: To describe the clinicopathologic characteristics of dogs with hyperadrenocorticism and concurrent pituitary and adrenal tumors. DESIGN: Retrospective study. ANIMALS: 17 client-owned dogs. PROCEDURE: Signalment, response to treatment, and results of CBC, serum biochemical analysis, urinalysis, endocrine testing, and histologic examinations were obtained from medical records of dogs with hyperadrenocorticism and concurrent adrenal and chromophobe pituitary tumors. RESULTS: On the basis of results of adrenal function tests and histologic examination of tissue specimens collected during surgery and necropsy, concurrent pituitary and adrenal tumors were identified in 17 of approximately 1,500 dogs with hyperadrenocorticism. Twelve were neutered females, 5 were males (3 sexually intact, 2 neutered); and median age was 12 years (range, 7 to 16 years). Hyperadrenocorticism had been diagnosed by use of low-dose dexamethasone suppression tests and ACTH stimulation tests. During high-dose dexamethasone suppression testing of 16 dogs, serum cortisol concentrations remained high in 11 dogs but decreased in 5 dogs. Plasma concentrations of endogenous ACTH were either high or within the higher limits of the reference range (12/16 dogs), within the lower limits of the reference range (2/16), or low (2/16). Adrenal lesions identified by histologic examination included unilateral cortical adenoma with contralateral hyperplasia (10/17), bilateral cortical adenomas (4/17), and unilateral carcinoma with contralateral hyperplasia (3/17). Pituitary lesions included a chromophobe microadenoma (12/17), macroadenoma (4/17), and carcinoma (1/17). CLINICAL IMPLICATIONS: Pituitary and adrenal tumors can coexist in dogs with hyperadrenocorticism, resulting in a confusing mixture of test results that may complicate diagnosis and treatment of hyperadrenocorticism.  相似文献   

11.
Cisternography combined with linear tomography was performed in ten clinically healthy dogs (weighing 14-33 kg) to visualize the pituitary gland, and results were compared with the results from sagittal midline computed tomography (CT) in these dogs. With cisternography, the length of the pituitary gland of nine dogs ranged from 5.7 to 9.9 mm (mean ± SD, 7.9 ± 1.3), and the width from 5.4 to 8.7 mm (6.4 ± 1.0). With sagittal linear tomography following cisternography, the height of the pituitary gland of these nine dogs ranged from 4 to 6 mm (5.1 ± 0.7); and, with sagittal CT, it ranged from 4.3 to 6 mm (5.0 ± 0.6). In an 11-year-old female Greyhound, two small nodules were found at the periphery of the pituitary gland using cisternography but were not recognized on CT images. It is concluded that cisternography combined with linear tomography is a safe and accurate alternative for the visualization of the pituitary gland when CT is not available.  相似文献   

12.
Nephrotomography and ultrasonography were used in 11 dogs with hyperadrenocroticism to assess the value of these techniques for the localization of biochemically diagnosed hyperfunctioning adrenocortical tumors. Both techniques enabled accurate localization of a unilateral adrenal mass in each of the dogs. Cross-sectional diameters of the masses ranged from 1 to 4 cm. In 1 dog, expansion of tumor into the caudal vena cava was revealed by caudal venacavography and ultrasonography. Mineralization in the tumor mass in 2 dogs was easily recognized by nephrotomography, but not by ultrasonography. Paracostal laparotomy confirmed the presence of an adrenocortical tumor in each dog, and expansion of tumor into the caudal vena cava in 1 dog. Cross-sectional diameters of the tumors ranged from 1.2 to 4.5 cm and corresponded well with cross-sectional measurements by nephrotomography and ultrasonography. It was concluded that nephrotomography and ultrasonography have similar diagnostic accuracies for the detection and localization of hyperfunctioning adrenocortical tumors.  相似文献   

13.
OBJECTIVE: To evaluate dogs with sudden acquired retinal degeneration syndrome (SARDS) for evidence of pituitary gland, adrenal gland, and pulmonary neoplasia and antiretinal antibodies and to evaluate dogs with neoplasia for antiretinal antibodies. ANIMALS: 57 clinically normal dogs, 17 with SARDS, and 53 with neoplasia. PROCEDURE: Thoracic radiography, ultrasonography of adrenal glands, and contrast-enhanced computed tomography of pituitary glands were performed in 15 dogs with SARDS. Western blot analysis was performed on sera of all dogs; recoverin (23 kd) and arrestin (48 kd) retinal antibodies were used as positive controls. RESULTS: Neoplasia was not detected via diagnostic imaging in dogs with SARDS. Western blot analysis revealed bands in all dogs ranging from > 48 to < 23 kd. Prominent bands with equivalent or greater density than 1 or both positive controls at the 1:1,000 dilution, and present at the 1:3,000 dilution, were detected in 28% of clinically normal dogs, 40% of dogs with neoplasia, and 41% of dogs with SARDS. No bands in dogs with SARDS had a consistent location of immune activity, and none were detected at the 23-kd site. The area around the 48-kd site had increased immune activity in all 3 groups. CONCLUSIONS AND CLINICAL RELEVANCE: The etiology of SARDS in dogs does not appear to be similar to cancer-associated retinopathy in humans on the basis of absence of differential antibody activity against retinal proteins. Although dogs with SARDS often have clinical signs compatible with hyperadrenocorticism, neoplasia of the adrenal glands, pituitary gland, or lungs was not detected.  相似文献   

14.
Trabecular bone morphometry was done on rib samples of beagles with hyperadrenocorticism and adrenal adenomas to evaluate bone loss and the remodeling changes responsible. Beagles diagnosed as having clinical hyperadrenocorticism and those with milder or subclinical hyperadrenocorticism diagnosed on the basis of adrenal and pituitary lesions at necropsy had increased adrenal and pituitary gland weights. In a group of dogs with adrenal cortical adenomas there was atrophy of remaining cortex, and the combined weight of adrenal glands or pituitary weights were not increased. In dogs with clinical hyperadrenocorticism, mean trabecular bone volume was 25% less than controls (P = 0.10). In both clinical and subclinical hyperadrenocorticism groups, the extent of trabecular surface with unmineralized osteoid matrix and osteoblasts was significantly reduced. There were no changes in resorption surfaces or number of osteoclasts present. No bone changes were seen in dogs with adrenal adenomas. In dogs with hyperadrenocorticism it appeared that decreased bone formation was primarily responsible for the relative osteopenia that developed. Although parathyroid glands were moderately enlarged in those dogs for which weights were available, the bone changes were not those of increased remodeling expected in hyperparathyroidism.  相似文献   

15.
Desmopressin is a synthetic analogue of the hypothalamic peptide vasopressin and binds to specific pituitary vasopressin (V3) receptors. The V3-receptor is overexpressed in pituitary corticotrope tumors and the injection of desmopressin induces a marked ACTH and cortisol release in human patients with pituitary- (PDH), but not adrenal tumor (AT) dependent hyperadrenocorticism. In this prospective study, we investigated the effects of desmopressin on serum cortisol levels in 80 dogs suspected of Cushing's syndrome. The aim was to find a sensitive and specific test to exclude AT. According to standard tests the dogs were divided into 3 groups (group 1=other disease, n=27; group 2=PDH, n=46; group 3=AT, n=7). Desmopressin was injected as an i.v. bolus of 4microg and serial blood samples were collected before and after 30, 60 and 90min. Desmopressin significantly stimulated cortisol release in dogs with PDH (median 51%, range -24 to 563%; p<0.0001), whereas no increase was seen in dogs with AT (median -12%, range -44 to 5%; p=0.063) and in controls (median +7%, range -36 to 196%; p=0.131). Using a cut off value of 10% increase over baseline, it was possible to exclude AT in 75% of patients. The results of this study suggest that the desmopressin test could be a useful tool in differentiating pituitary from adrenal dependent Cushing's syndromes. Additional dogs with adrenocortical tumor must be tested in order to recommend its use in clinical practice.  相似文献   

16.
BACKGROUND: Pituitary masses in dogs are not uncommon tumors that can cause endocrine and neurologic signs and, if left untreated, can decrease life expectancy. HYPOTHESIS: Dogs with pituitary masses that received radiation therapy (RT) have more favorable neurologic outcomes and longer survival times compared with untreated dogs. ANIMALS: Nineteen dogs with a pituitary mass identified on CT or MR imaging were irradiated with 48 Gy given in 3 Gy daily-dose fractions. Twenty-seven untreated control dogs had pituitary masses. METHODS: Medical records of dogs with pituitary masses were retrospectively reviewed for clinical signs, mass size, and outcome. RESULTS: Median survival time was not reached in the treated group. Mean survival time in the treated group was 1,405 days (95% confidence interval [CI], 1,053-1,757 days) with 1-, 2-, and 3-year estimated survival of 93, 87, and 55%, respectively. Median survival in the nonirradiated group was 359 days (95% CI, 48-916 days), with a mean of 551 days (95% CI, 271-829 days). The 1-, 2-, and 3-year estimated survival was 45, 32, and 25%, respectively. Dogs that received RT for their pituitary tumors had significantly longer survival times than untreated dogs (P = .0039). Treated dogs with smaller tumors (based on maximal pituitary-to-brain height ratio or area of tumor to area of brain) lived longer than those with larger tumors (P < .001). CONCLUSIONS AND CLINICAL IMPORTANCE: When compared with untreated dogs, RT increased survival and controlled neurologic signs in dogs with pituitary masses.  相似文献   

17.
X-ray-computed tomography (CT), nephrotomography, and ultrasonography were performed in 10 clinically healthy dogs (weighing 14 to 33 kg) to visualize the adrenal glands. In all 10 dogs, CT enabled visualization of both adrenal glands. Cross-sectional diameter was measured accurately. The size and shape of CT sections of the adrenal glands varied widely because of individual differences in the actual size and shape of the adrenal glands and because of their position in the plane of the CT scans. In 5 dogs, nephrotomography enabled visualization of 1 or both adrenal glands as oblong craniocaudal-directed densities in the craniodorsal portion of the abdomen. In 7 dogs, transverse ultrasonography enabled visualization of 1 or both adrenal glands as round or oval hypoechoic structures in the surrounding hyperechoic fat.  相似文献   

18.
OBJECTIVE: To determine the reproducibility and accuracy of computed tomographic (CT) measurements of pituitary gland dimensions in healthy dogs. ANIMALS: 35 healthy sexually intact adult dogs. PROCEDURES: 2 observers independently viewed CT images of the skull in 35 dogs twice. Pituitary gland height, width, length, and volume and pituitary gland height-to-brain area ratio (P:B ratio) were measured or calculated. Intraobserver and interobserver agreement indexes (AIs) were calculated for pituitary gland dimensions. Computed tomography was performed also on 5 phantoms, and both observers measured phantom dimensions twice. True-value AIs were calculated for the phantom study. RESULTS: The mean +/- SD interobserver AI between observer 1 and 2 for pituitary gland height and the P:B ratio was 0.90 +/- 0.07. The intraobserver AI for pituitary gland height and the P:B ratio was 0.97 +/- 0.04 for observer 1 and 0.94 +/- 0.04 for observer 2. The intra and interobserver AIs for the other dimensions were lower than those for pituitary gland height and the P:B ratio. All phantom dimensions on CT images were underestimated significantly, compared with their true values. CONCLUSIONS AND CLINICAL RELEVANCE: The intra- and interobserver AIs for pituitary gland dimension measurements on CT images were high. However, the same observer preferably should perform serial measurements. Window settings influence pituitary gland dimension measurements, and predetermined window settings are recommended to make comparisons among dogs. Pituitary gland dimension measurements made from CT images in our study underestimated the true values.  相似文献   

19.
BACKGROUND: Pituitary apoplexy in humans is a clinical syndrome resulting from sudden infarction, hemorrhage, or both in a normal or an adenomatous pituitary gland. OBJECTIVE: Describe a clinical syndrome in dogs similar to pituitary apoplexy in humans. ANIMALS: Four dogs exhibiting a sudden onset of neurologic signs. METHODS: A retrospective study was used, including clinical examination, computed tomography (CT), postmortem examination, and histopathology of the brain. Pituitary tissue from 3 of the dogs was subjected to immunocytochemistry. RESULTS: Four dogs (2 Mongrels, 1 Bordeaux Dog, and 1 Cocker Spaniel; median age, 11 years; median body weight, 20.5 kg) presented with acute neurologic signs including depression (n = 3), behavioral changes (n = 1), vision loss (n = 1), seizures (n = 1), and collapse (n = 1). CT disclosed suprasellar infarction, hemorrhage, or both associated with a pituitary macroadenoma in 3 dogs and a frank hemorrhage in a nonadenomatous pituitary gland in 1 dog. CT findings were correlated with postmortem findings, and pituitary apoplexy was confirmed by histopathology and immunocytochemistry of the pituitary tissue. CONCLUSIONS AND CLINICAL IMPORTANCE: This study provides histopathologic evidence of pituitary apoplexy in dogs. The results are relevant for future diagnosis and treatment of pituitary disease in dogs.  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   

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