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1.
Progesterone and estrogens play key roles in regulating various physiological phenomena related to normal growth, development, and reproduction of domestic animals. This review focuses on the mechanisms by which progesterone and estrogens regulate the reproductive processes in these animals. The majority of research on the actions of progesterone and estrogens on the reproductive systems of cattle, sheep, and pigs has been genomic in nature and represents attempts to better understand how these steroids regulate gene expression. Results of recent research suggest that progesterone and estrogens can alter target cell responses nongenomically via membrane receptors. The characteristics of membrane receptors for progesterone and estrogen in various cell types are described and the intracellular signal pathways defined. Estrogens acting via membrane receptors can suppress LH secretion by gonadotropes and stimulate rapid increases in uterine blood flow. Progesterone acting via a membrane receptor has been shown to inhibit binding of oxytocin to oxytocin receptors in isolated endometrial plasma membranes and stimulate capacitation of spermatozoa. Results of research suggest that progesterone and estrogens can act nongenomically to alter target cell responses in domestic animals. The biological implications of this mode of action in these animals are discussed. 相似文献
2.
Estrogen receptor in bovine skeletal muscle 总被引：2，自引：0，他引：2
In connection with investigations of the anabolic action of estrogens, we examined skeletal muscle of veal calves for estradiol receptors. The high speed supernatant of muscle homogenate was incubated with .5 nM 3H-estradiol and for the determination of nonspecific binding with .5 nM 3H-estradiol plus 13 nM estradiol at 0 C overnight. After treatment with charcoal two times, the supernatant was analyzed by agar gel electrophoresis. Specific binding was found in the typical position of cytosolic estradiol receptor. Ninety percent of 3H-estradiol binding was suppressed by estradiol-17 beta, zeranol, estrone or diethylstilbestrol, but was not affected by testosterone, dihydrotestosterone, trenbolone or progesterone. The specific binding activity varied between .3 and 2.0 fmol/mg protein and the dissociation constant of the receptor was Kd = 60 pM. After an enrichment up to 42 fmol/mg cytosolic protein using heparin sepharose, the receptor remained unchanged as determined by agar gel electrophoresis. Although uterine tissue generally contains 1,000 times more estradiol receptors, these results clearly demonstrate that skeletal muscle also contains estradiol receptors with identical properties. This indicates that one possible component of the anabolic action of estrogens may be the direct stimulation of the muscle via the estradiol receptor. 相似文献
3.
A G Rico 《Journal of animal science》1983,57(1):226-232
The endogenous anabolic agents, estradiol-17 beta, progesterone and testosterone are steroids that are quickly metabolized by the liver and are not very active when administered orally. Estradiol-17 beta is excreted by the bovine in bile as free estradiol-17 alpha, and by swine, in urine, as glucuronides and sulfates. In ruminants, the primary metabolite of progesterone is pregnandiol and that of testosterone is epitestosterone. In horses, the metabolites of these compounds are primarily 17 ketosteroids. Esters of the endogenous anabolic agents are rapidly hydrolyzed and the nonesterified forms follow the same biotransformation pathways as the natural compounds biosynthesized by the animal. The exogenous anabolic agents, such as trenbolone acetate, zeranol and diethylstilbestrol, may be active by the oral route and are less readily metabolized in the liver than the endogenous anabolics. Their metabolic pathways may be complex and lead to excreted forms after glucuronide conjugation. With respect to biochemical mechanism of action, it can be assumed that the anabolics act like all steroids by way of intracellular receptors. Biotransformations could lead to more reactive molecules that may bind themselves to normal constituents of the organism. Bound metabolites are generally formed later than free metabolites, and are considered less toxic with a lower level of bioavailability. 相似文献
4.
Kusuda S Morikaku K Kawada K Ishiwada K Doi O 《The Journal of reproduction and development》2007,53(1):143-150
The aim of the present study was to establish a simple method to monitor ovarian activity and non-invasively diagnose pregnancy in okapi (Okapia johnstoni). The feces of a female okapi were collected daily or every 3 days for 28 months. Steroids in lyophilized feces were extracted with 80% methanol, and the fecal levels of immunoreactive progestagens (progesterone and pregnanediol-glucuronide), androgen (testosterone), and estrogens (estradiol-17beta and estrone) were determined by enzyme immunoassays with commercially available antisera. Using the progesterone profiles, the durations of the luteal phase, follicular phase, and estrous cycle were determined to be 11.1 +/- 0.4, 5.3 +/- 0.6, and 16.5 +/- 0.7 days (n=22), respectively. Fecal levels of immunoreactive progesterone, pregnanediol glucuronide, and testosterone gradually increased from early pregnancy and peaked several months before parturition. More pregnanediol glucuronide was excreted in feces than progesterone during late pregnancy, but not during the estrous cycle. Although the fecal concentrations of immunoreactive estradiol-17beta and estrone change a little throughout pregnancy and non-pregnancy, they rose sharply and temporarily on the day following parturition. The present study indicates that fecal assays with commercial antisera for progesterone and pregnanediol glucuronide are useful for evaluating luteal activity and diagnosing pregnancy and indicates that estrogens might have some role as a trigger of parturition. 相似文献
5.
Until 1999 it was accepted that pheromones act exclusively by stimulating the dendritic receptors present in olfactory epithelium. Cycling gilts with an experimentally-disrupted neural olfactory pathway were used to test the hypothesis that boar pheromone 5alpha-androstenol may affect the secretion of hormones involved in the regulation of the estrous cycle by the humoral pathway. On day 12 of the estrous cycle the nasal cavity of gilts (n=15) was irrigated with zink sulfate solution. From day 16 to 20, the experimental group (n=10) was injected intramuscularly with 5alpha-androstenol (20 microg) twice a day. Blood samples were collected from the jugular vein at 4 h intervals on days 17-21 to estimate plasma concentration of LH, oxytocin, estradiol-17beta, testosterone and progesterone. The experimental group displayed a significantly lower mean concentration of LH than the control animals (P<0.0001). The decrease in concentration of LH was accompanied by the reduction of oxytocin (P<0.001), estradiol-17beta (P<0.001) and testosterone (P<0.01) secretion. These results demonstrated that 5alpha-androstenol influenced hormonal regulation by humoral pathway and might be considered to be the priming pheromone in gilts. 相似文献
6.
Over the last few years, rapid and physiologically important non-genomic actions of all classes of steroid hormones have been described in many cell types. A putative non-genomic membrane progesterone receptor (NGPR) was the first, and so far the only, non-genomic steroid receptor cloned. Two homologous NGPR proteins have been identified in the human, and a similar protein in the bovine and rat. Various detection methods have been used to identify putative NGPRs in a range of tissues: however, different methods often yield quite different molecular weights, and probably detect distinct moieties. We describe some properties of the specific cell-surface membrane binding sites for [3H]-progesterone in enriched cell membrane preparations of bovine luteal and follicular cells. Similar binding sites were also detected in cell-membranes of some (but not all) bovine tissues. Western blots of detergent extracts of bovine luteal membranes identified a protein (85kDa) that reacted with an antiserum to the N-terminal peptide of porcine NGPR. Activity was low in native non-denatured extracts, but increased dramatically in a dose-dependent manner following pretreatment with the cholesterol-complexing agent, digitonin. This protein was co-precipitated by antisera to caveolin. In contrast, a specific monoclonal antibody to the ligand binding domain of the genomic progesterone receptor (Mab C262) detected two proteins (M(r), 55 and 60kDa) in luteal membrane detergent extracts. Immunostaining of these proteins by Mab C262 was abolished by digitonin concentration-dependent manner in non-denatured extracts. However, both proteins were unaffected by digitonin in fully denatured detergent extracts, suggesting that digitonin induced a conformational change in the native protein that prevented binding of Mab C262 to its epitope. Our data suggest the presence of a complex of two or more distinct membrane-associated progesterone-binding proteins in bovine luteal membranes. Moreover, their conformations are specifically affected by removal of bound cholesterol. 相似文献
7.
Interactions of insulin-like growth factors (IGFs) from recombinant human and natural ovine sources with sheep liver plasma membranes have been studied. Total specific binding of 125I-hIGF-II (40%) to liver plasma membranes greatly exceeded that of 125I-hIGF-I (1.5%) after incubation at 20 C for 90 min. Binding of 125I-hIGF-II to the plasma membranes was dependent upon time, temperature and membrane concentration of the incubation. Binding of 125I-hIGF-II was only partially reversed by addition of 100 nM IGF-II (18%) or by dilution with excess buffer (36%). Competitive inhibition studies of 125I-hIGF-II binding demonstrated that IGF-II from ovine or recombinant human sources was more effective at inhibiting binding than ovine or human IGF-I. Insulin did not affect binding of 125I-hIGF-II. Plasma membranes were affinity cross-linked to 125I-IGF-II followed by sodium dodecyl sulfate polyacrylamide gel electrophoresis in the presence and absence of the reducing agent dithiothreitol. Following autoradiography, radioactive bands were localized at 274,000 Mr and 210,000-215,000 Mr in the presence and absence of reducing agent, respectively. This pattern was unaffected by 100 nM human or ovine IGF-I or 1,000 nM insulin, but coincubation with 100 nM human or ovine IGF-II eliminated the radioactive band. These data indicate that an IGF-II specific receptor is present in sheep liver plasma membranes which has characteristics similar to those of nonruminant Type II receptors. 相似文献
8.
Kieborz-Loos KR Garverick HA Keisler DH Hamilton SA Salfen BE Youngquist RS Smith MF 《Journal of animal science》2003,81(7):1830-1836
The purpose of the present study was to determine the effect of progesterone or progesterone + estradiol-17beta on oxytocin-induced prostaglandin F2alpha (PGF2alpha) secretion in postpartum beef cows. Thirty-four anestrous postpartum beef cows were ovariectomized (d 32 [Groups 1 to 3] or d 23 [Groups 4 to 6] postpartum [d 0 = parturition]) and allotted to six treatments (Group 1; negative control) to simulate short (Groups 2 through 5) or normal (Group 6) length estrous cycles. Steroid treatments for the respective groups were as follows: Group 1) no estradiol-17beta or progesterone treatment (n = 8; negative control); Group 2) progesterone (d 34 to 40; n = 6); Group 3) estradiol-17beta (d 32 to 33) and progesterone (d 34 to 40; n = 6); Group 4) progesterone (d 23 to 29), no estradiol-17beta (d 32 to 33), and progesterone (d 34 to 40; n = 5); Group 5) progesterone (d 23 to 29), estradiol-17beta (d 32 to 33), and progesterone (d 34 to 40; n = 5); and Group 6) progesterone (d 23 to 29), estradiol-17beta (d 32 to 33), and progesterone (d 34 to 50; n = 4; positive control). Oxytocin (100 IU) was injected (i.v.) at the end of each treatment to test the ability of the postpartum uterus to secrete PGF2alpha as measured by a stable metabolite of PGF2alpha, 15keto-13,14 dihydro-PGF2alpha (PGFM). Peak concentrations ofPGFM (P < 0.08) and total PGFM secreted (area under the curve; P < 0.05) were increased on d 6 following first (Group 2) or second (Group 4) exposure to progesterone and were similar to peak concentrations and total PGFM secreted 16 d following a simulated normal estrous cycle (Group 6). Administration of estradiol-17beta before first progesterone exposure (Group 3) did not reduce peak concentrations of PGFM or total PGFM secreted relative to the preceding groups. Peak concentrations of PGFM (P < 0.08) and total PGFM secreted (P < 0.05) were reduced following a second progesterone exposure, provided that cows were pretreated with estradiol-17beta (Group 5). In summary, oxytocin-induced release of PGFM was inhibited on d 6 following second exposure to progesterone only when cows were pretreated with estradiol-17beta. Therefore, estradiol-17beta and progesterone were both associated with the timing of PGF2, secretion in postpartum cows. 相似文献
9.
Bronneberg RG Taverne MA Dieleman SJ Decuypere E Bruggeman V Vernooij JC Stegeman JA 《Domestic animal endocrinology》2007,32(1):15-28
In this study we investigated the temporal relationship between ovulation, egg formation, oviposition and the changes in plasma concentrations of progesterone, luteinizing hormone and estradiol-17beta during the egg laying cycle in farmed ostriches. In 10 egg-producing birds, transcutaneous ultrasound scanning was performed at 3h intervals and blood sampling at hourly intervals during a period of at least 48h (one egg laying cycle). In hens (n=8) that ovulated during the observational period, the ovulated egg was first detected 2h after oviposition; thus, ovulation occurred shortly after oviposition in all birds. During the period between two consecutive ovipositions, the developing egg remained for 9h in the proximal part (infundibulum, magnum or isthmus) and for 39h in the distal part of the oviduct (uterus). In ovulating hens, plasma progesterone concentrations showed a characteristic and consistent profile: from basal levels of around 0.1ng/ml concentrations started to increase 12h before oviposition, reached an average maximum of 3.5ng/ml at 3h before oviposition and returned to basal levels 3h and 30min after oviposition. Changes in plasma luteinizing hormone and estradiol-17beta concentrations showed comparable patterns of elevation and decline relative to the timing of oviposition and ovulation. However, variation in their individual basal concentrations was generally larger and peak values were less conspicuous than those of progesterone. In non-ovulating hens (n=2) neither progesterone, nor luteinizing hormone nor estradiol-17beta showed elevations to peak concentrations before oviposition. These data demonstrate that during the egg laying cycle of ostriches, events such as ovulation, egg development and oviposition evolve according to a rather strict time schedule, and that progesterone, luteinizing hormone and estradiol-17beta reach peak concentrations shortly before ovulation. Additionally, our findings also show that on-farm ultrasound scanning is a useful technique to discriminate between ovulating and non-ovulating hens. 相似文献
10.
Meishan pigs are known for their early sexual maturity. On the other hand, they grow slowly. There is no information currently available about the combination of these two characteristics in Meishan pigs. To study the developmental characteristics of Meishan pigs, the plasma concentrations of LH, FSH, inhibin, testosterone, estradiol-17beta, progesterone and insulin-like growth factor-I (IGF-I) in young Meishan boars were determined using RIA and ELISA. Inhibin decreased with age in weeks, while testosterone and estradiol-17 beta increased. Testosterone increased gradually, and an increase in estradiol-17beta occurred after sexual maturity. IGF-I increased before puberty and subsequently decreased just after puberty like a pubertal IGF-1 surge. FSH, LH and progesterone did not change with age. There was no significant correlation among the hormones. During the experimental period, the Meishan boars showed large individual differences. These differences may depend on the fact that Meishan boar reach maturity at 12 weeks of age and continue to grow thereafter. 相似文献
11.
Deciduosarcoma is a rare, hormonally dependent neoplasm with features of malignancy, previously reported only in rabbits enrolled in chronic toxicology studies involving estrogens with or without progestins. An exploratory laparotomy was performed on a 6-year-old pet Dutch dwarf rabbit following palpation of a 6-cm-diameter abdominal mass. Grossly, the mass was fleshy and nodular, adhered to but not appearing to originate from the small intestine, with a smaller mass of similar appearance involving the uterus, and an effaced mesenteric lymph node. Histologically, the mass was characterized by spindloid cells and large epithelioid cells with abundant pale eosinophilic vacuolated cytoplasm and an infiltrative pattern of growth. Giant cells with large, bizarre, hyperchromatic nuclei were common. Cells were positive by immunohistochemistry for vimentin and progesterone and estrogen receptors and negative for pancytokeratin (AE1/AE3), cytokeratin 18, desmin, alpha-smooth muscle actin (SMA), and CD10. Based on histologic and immunohistochemical findings, a diagnosis of deciduosarcoma was made. 相似文献
12.
Yang P Medan MS Arai KY Watanabe G Taya K 《The Journal of reproduction and development》2005,51(3):353-358
The present study was undertaken to determine changes in circulating levels of immunoreactive (ir)-inhibin, FSH, LH, estradiol-17beta, progesterone, and testosterone during the ovulatory cycle of Shao ducks. Serial blood samples were taken from two groups of laying ducks for measurement of ir-inhibin, gonadotropins, and steroid hormones at 2 h intervals for 24 h. Plasma concentrations of ir-inhibin did not change significantly during the ovulatory cycle. The highest level of plasma ir-inhibin was observed 6 h prior to ovulation, which coincided with a decreased level of plasma FSH. One FSH surge was found 12 h after ovulation. Estradiol-17beta, progesterone, and testosterone were also determined during the ovulatory cycle. Two peak values were detected for estradiol-17beta 8 h before ovulation and 4 h after ovulation, while progesterone started to increase 4 h before ovulation and reached a peak at ovulation. The highest level of plasma testosterone was detected around the time of ovulation. These results suggest that inhibin may be involved in the control of FSH secretion during the ovulatory cycle. In addition, both LH and progesterone are of importance in the ovulation process of Shao ducks. 相似文献
13.
14.
The present study undertook chemical analysis of components of Pfaffia paniculata roots. In addition, an animal experiment was conducted in which mice had ad libitum access to water enriched with powdered P. paniculata root for 30 days. Changes in plasma concentrations of estradiol-17beta and progesterone in female mice and of testosterone in male mice were ascertained. The results revealed that P. paniculata roots contain two types of phytosteroids, beta-sitosterol and stigmasterol, in addition to other compounds such as pfaffic acid, allantoin, saponins, beta-sitosteryl-beta-D-glucoside, and stigmasteryl-beta-D-glucoside. Regarding changes in plasma concentrations of hormones, levels of the sex hormones estradiol-17beta, progesterone and testosterone were clearly higher for mice that drank P. paniculata root-enriched water than for mice that drank plain water. Powdered P. paniculata root is easily dissolved in feed or water, and as no adverse reactions were seen in mice within 30 days of oral intake, consumption of P. paniculata for long periods of time appears safe. 相似文献
15.
Tohei A Shi FX Ozawa M Ima K Takahashi H Shimohira I Kojima T Watanabe G Taya K 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2001,63(1):45-50
To elucidate the effects of ultrasound-guided transvaginal follicular aspiration, plasma concentrations of FSH, LH, inhibin, estradiol-17beta and progesterone, and folliculogenesis were examined in Holstein cows. Four clinically healthy cows with regular estrous cycles were scanned by ultrasound per rectum once a week for 9 weeks before the commencement of follicular aspiration. All visible follicles were divided into 3 categories based on their sizes (2 < or = small < 5 mm; 5 < or = medium < 10 mm, large > or = 10 mm). The follicular aspiration was started at random during the estrous cycle and conducted under epidural anesthesia induced with 5 ml of 2% lidocaine once a week for 6 weeks. The average number of total visible follicles > or = 2 mm in diameter at 7 days after aspiration (21.7 +/- 7.4, n = 24) was similar to that before starting aspiration (26.7 +/- 10.5, n = 36). Plasma inhibin and estradiol-17beta declined and fell to a trough on 1.5 days and returned to pre-aspiration values by 5 days after aspiration. Plasma concentrations of FSH increased and reached peak levels between 1 and 1.5 days after aspirations. Plasma concentrations of LH also increased and reached peak levels between 0.5 and 1.5 days after aspirations. Both plasma FSH and LH had returned to pre-aspiration levels by 5 days after aspirations. Plasma concentrations of progesterone did not change with the follicular aspiration. These results demonstrate that follicular aspiration decreases plasma concentrations of inhibin and estradiol-17beta, which in turn leads to a rise in plasma concentrations of FSH and LH. It is suggested that marked increases in plasma concentrations of FSH and LH after the aspiration stimulate the development and maturation of a new cohort of follicles within one week in cows. 相似文献
16.
The aim of this study was to compare the changes in hormonal profiles during ovsynch and ovsynch plus norprolac treatment
in Murrah buffalo heifers following timed artificial insemination (TAI) at stressful summer months, through intensive endocrine
analysis. The norprolac (an anti-prolactin drug) at the dose rate of 10.0 mg/animal /day effectively suppressed the level
of prolactin upto 30 hours. The hormones quantified in blood plasma samples collected before, during and after ovsynch and
ovsynch plus norprolac treatment were LH, prolactin, progesterone, estradiol–17β and total estrogens. The plasma prolactin
and progesterone concentrations were negatively correlated (r = − 0.24) during summer estrous cycle, which indicated prolactin-induced
suppression of progesterone secretion through poor luteal development. The ovsynch treatment reduced the incidence of anestrous
from 45% before treatment to only 18% after treatment. The norprolac induced prolactin suppression improved the efficiency
of ovsynch treatment upto 100% cyclicity after treatment in comparison to 36% acyclicity before treatment. In both the treatments
45% and 55% of animal became pregnant after TAI, respectively. The high prolactin secretion contributed to poor fertility
by lowering gonadal hormones (estradiol-17β, total estrogens and progesterone) production in summer months. This finding of
endocrine changes suggests that ovsynch protocol for estrus synchronization has potential application for improvement of fertility
in repeat breeding buffaloes even during extreme summer months through suppression of prolactin secretion. 相似文献
17.
The present studies were conducted: (1) to determine which beta-adrenoceptor subtypes are involved in progesterone and oxytocin (OT) secretion, (2) to examine whether noradrenaline (NA) acts directly on the cytochrome P-450scc and 3 beta-hydroxysteroid dehydrogenase (3 beta-HSD), and (3) to study the effect of prostaglandin F2 alpha (PGF2 alpha) on NA-stimulated steroidogenesis in luteal cells. The effect of NA on progesterone secretion from luteal slices of heifers on days 8-12 of the oestrous cycle was blocked by both atenolol (beta 1-antagonist) and ICI 118.551 hydrochloride (beta 2-antagonist). OT secretion was blocked only after treatment with ICI 118.551 hydrochloride (P < 0.05). Dobutamine (10(-4)-10(-6) M), a selective beta 1 agonist and salbutamol (10(-4)-10(-6) M), a selective beta 2 agonist, both increased progesterone production (P < 0.01) with an efficiency comparable to that produced by NA (P < 0.01). The increase of OT content in luteal slices was observed only after treatment with salbutamol at the dose of 10(-5) M (P < 0.01). Dobutamine had no effect on OT production at any dose. A stimulatory effect of NA on cytochrome P-450scc activity (P < 0.05) was demonstrated using 25-hydroxycholesterol as substrate. 3 beta-HSD activity also increased following NA (P < 0.01) or pregnenolone (P < 0.05) and in tissue treated with pregnenolone together with NA (P < 0.01). PGF decreased progesterone synthesis (P < 0.05) and 3 beta-HSD activity (P < 0.01) in tissue treated with NA. We conclude that NA stimulates progesterone secretion by luteal beta 1- and beta 2-adrenoceptors, while OT secretion is probably mediated only via the beta 2-receptor. NA also increases cytochrome P-450scc and 3 beta-HSD activity. PGF inhibits the luteotropic effect of NA on the luteal tissue. 相似文献
18.
Kobayashi A Katagiri S Kimura T Ochiai K Umemura T 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2002,64(9):773-777
The direct effects of three steroid hormones (progesterone, estradiol-17beta and corticosterone) on the growth of Neospora caninum (N. caninum) tachyzoite were examined in Vero cells. Subsequently, ovariectomized BALB/c mice infected with N. caninum were treated with physiological concentrations of the steroid hormones for 1 or 2 weeks. These hormones had no direct effect on the parasite growth in vitro. In the infected mice, there was no significant difference in the parasite distribution and histopathological changes between the hormone-injected and control groups. No mice showed parasitemia at the time of autopsy. These results suggest that physiological levels of steroid hormones (progesterone, estradiol-17beta and corticosterone) do not reactivate N. caninum in mice. 相似文献
19.
Bacteriology, histology, and scanning electron microscopy were used to evaluate uterine involution in 27 mares treated with daily injections of 150 mg of progesterone and 10 mg of estradiol-17 beta, commencing within 18 hours of parturition. These findings were compared with those for 24 untreated mares at postpartum day 10 or 11. The treatment resulted in significantly (P less than 0.05) greater uterine gland proliferation. Gland density was significantly (P less than 0.05) greater in mares treated for 6 to 10 days than in those treated 2 to 5 days. The proportion of ciliated cells to secretory cells lining the endometrial surface was significantly (P less than 0.05) greater in mares during delayed foal estrus than in those at postpartum days 10 to 11. The proportion of ciliated to secretory cells increased with increasing duration of treatment. It was concluded that treatment with progesterone and estradiol-17 beta allowed additional time for uterine involution in the early postpartum period. 相似文献
20.
Ishikawa A Kikuchi S Katagiri S Sakamoto H Takahashi Y 《The Japanese journal of veterinary research》2002,50(1):17-27
The present study aimed to establish simple systems for measuring fecal steroid hormones in order to monitor the reproductive profiles of captive Hokkaido brown bears. The efficiency of fecal sample processing at the steps of dehydration and extraction and the correlation between steroid concentrations in matched fecal and blood samples were studied. Then, monthly changes in fecal estradiol-17 beta and progesterone in female bears, and testosterone in male bears were examined. The procedure was finalized as follows. Fecal samples were dried at 100 degrees C for 3 hr and extracted with diethyl ether. The diethyl ether in the extracts was evaporated and residues were reconstituted in ethanol for the assays. Hormone concentrations were quantified using enzyme immunoassays. Concentrations of progesterone and testosterone in fecal and plasma samples were correlated in the systems. The changes in fecal progesterone and testosterone concentrations were similar to those in serum concentrations of bears as reported previously. In contrast, fecal estradiol concentrations did not correlate with plasma levels probably because of the time lag in excretion. However, the changes in estradiol-17 beta concentrations in feces in the present study were similar to those reported in serum. In conclusion, fecal progesterone and testosterone assay systems appear practical for monitoring ovarian and testicular activities without immobilization, though methodological improvements and further validation may be required. For the fecal estradiol-17 beta assay, there is a need to solve the problem of excretion time lag before the system can be used in the study of reproductive physiology. 相似文献