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Query: UMLS:C0432222 (SEM)
 47,337 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The capability of pregnant mare serum (PMS) and human chorionic gonadotropin (HCG) to induce estrus and ovulation was tested in mature, anestrous bitches. The PMS was given for 10 consecutive days in 1 of 3 regimens: 500 IU/day (experiment 1), 250 IU/day (experiment 2), or 20 IU/kg/day (experiment 3). The HCG was given as a single 500-IU dose on experimental day 10. Controls were given saline solution. Vaginal smears were collected on days 1, 3, 5, 7, 9, and 12 by jugular venipuncture, and the plasma was assayed for progesterone concentration by radioimmunoassay. On day 13, the bitches were euthanatized, ova were flushed from the uterine tubes (oviducts), and the ovaries were collected and prepared for microscopic examination. Fourteen of 25 bitches treated with PMS and HCG showed estrus and ovulated. Proestrus (vaginal bleeding) commenced between experimental days 7 and 10. Estrus commenced on day 9 or 10. Progesterone increased from approximately 1 ng/ml on day 1 to more than 6 ng/ml on day 12. Numbers of ovulation sites on both ovaries were 4.7 +/- 1.1 and 4.6 +/- 0.5 (mean +/- SEM) in those given the daily doses of 500 and 250 IU of PMS and 9.8 +/- 1.5 in experiment 3 bitches. Eleven hormone-treated dogs and 7 saline-treated dogs did not show any detectable response. Neither cystic nor unovulated, luteinized follicles appeared on the ovaries.
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PMID:Induction of estrus and ovulation in the bitch, using exogenous gonadotropins. 55 42

Lactation pseudopregnancy in rats suckling a 5-pup litter lasted 22.0 +/- 0.4 days (mean +/- SEM; n = 11). By day 13 of lactation (day 1 of lactation = day of parturition), the continuation of lactation pseudopregnancy was dependent on the suckling stimulus, as litter removal on day 13 resulted consistently in ovulation on day 16. Measurements of various hormones before and after litter removal revealed high concentrations of progesterone and PRL during lactation and a rapid drop of both hormone concentrations after litter removal. Lactation pseudopregnancy in rats suckling a 10-pup litter lasted 26.1 +/- 0.9 days (n = 16). After litter removal on day 13 of lactation, the lactation pseudopregnancy continued for a further 7- to 11-day period, as evidenced by daily vaginal smears which remained mucified during that period. Measurements of hormone concentrations revealed continuously high concentrations of PRL before litter removal and a pattern of PRL secretion characterized by at least two diurnal peaks during the first days after litter removal. Progesterone concentrations decreased by 50% after litter removal, but the levels then remained constant and well above those found after the removal of 5-pup litters. It is argued that the different response to litter removal on day 13 of lactation between rats suckling 5 or 10 pups is due to the initiation of PRL peaks in rats with 10-pup litters: these PRL peaks are able to maintain luteal function for some period. It is further argued that the initiation of PRL peaks in rats with 10-pup litters is due to the high blood concentrations of progesterone at the time of litter removal compared to those of rats with a 5-pup litter.
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PMID:Suckling stimulus, lactation, and suppression of ovulation in the rat. 74 25

Whether the placenta is a target tissue for estrogens and progesterone, and their putative mechanism of action, is still a controversial question in the literature. The effect of progesterone and estradiol on 3',5'-cyclic adenosine monophosphate (cAMP) and inositol phosphates generation in human term placenta was investigated. Placental explants were incubated in vitro for up to 48 h in the absence and in the presence of estradiol, progesterone or both steroids (0.1 mumol/l final concentration in all cases), and were stimulated with terbutaline, a beta-adrenergic agonist, (0.1 mmol/l) or angiotensin II (1 mumol/l). The cAMP content was measured by a competitive protein binding assay, and the generation of labelled inositol phosphates formation in explants prelabelled with 3H-myo-inositol was measured by anion exchange chromatography. Progesterone increased significantly basal cAMP concentrations in comparison with control or estradiol-treated tissues (169 +/- 13, 72 +/- 8, and 69 +/- 2 pmol/g wet wt tissue, mean +/- SEM, respectively). However, following terbutaline stimulation cAMP levels (mean +/- SEM) increased to similar values under all conditions (182 +/- 33, 197 +/- 36, and 237 +/- 17 pmol/g wet wt tissue for control, estradiol-, and progesterone-treated tissues, respectively). Angiotensin II stimulated inositol phosphates generation in placental explants by an average of fivefold, but this increase was significantly reduced in the presence of progesterone (5.2 +/- 0.7, 3.7 +/- 0.4, and 2.2 +/- 0.3 fold increase vs non-angiotensin-stimulated tissues, for control, estradiol-, and progesterone-treated placenta, mean- +/- SEM, respectively). These data suggest that progesterone modulates the formation of second messengers in human placenta at term.
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PMID:Progesterone increases basal 3',5'-cyclic adenosine monophosphate formation and down-regulates the agonist-induced inositol phosphates generation in human term placenta. 133 36

The aim of this study was to investigate the importance of inhibin in the delay in return to oestrus in heifers induced by steroid-stripped bovine follicular fluid (bFF). Oestrous activity was synchronized in 18 Hereford x Friesian heifers with two injections of prostaglandin (PG) 12 days apart. At the time of the second PG injection (time 0), the animals were assigned at random to one of three experimental groups and received i.v. injections of 20 ml saline (controls, n = 6), whole bFF (FF group, n = 6) or bFF in which the bioactive inhibin content had been reduced by > 95% by immunoaffinity chromatography (-INH group, n = 6; inhibin content approximately 0.8 ml whole bFF) every 8 h for 2 days. In a dose-response study, 2.5 ml whole bFF was insufficient to delay oestrus consistently following a similar synchronization regimen. Blood samples were taken every 8 h, initially before each injection and then subsequently for a further 9 days for hormone analysis. Animals were observed every 8 h throughout the experiment for signs of behavioural oestrus. The ovaries of all animals were examined using real-time ultrasonography about 30 h after the second PG injection. Treatment failed to suppress peripheral follicle-stimulating hormone (FSH) concentrations, although a significant increase was observed in both treatment groups after cessation of injections. Progesterone concentrations fell immediately after the second PG injection in all animals and remained below minimum detectable concentrations in all treated animals for the remainder of the experiment. In control animals, progesterone rose above minimum detectable concentrations by day 6 and continued to rise until the end of the experiment. Analysis of samples taken from treated animals several days after observed oestrus revealed that all had apparently ovulated. Mean daily luteinizing hormone (LH) concentrations did not differ between treatment groups before ovulation, but after ovulation, mean daily LH was significantly reduced in control animals as progesterone concentrations rose. Follicular development, as assessed by the mean antral diameter of the largest follicle on a pair of ovaries at ultrasound examination, was significantly suppressed in treated animals compared with controls (P < 0.01) and there was no significant difference (P = 0.397) between the two treatment groups. Control animals displayed oestrus 68 h (+/- 8 SEM) after the second PG injection, but oestrus was delayed in treated animals to 186h +/- 5 (FF group) and 191 h +/- 6 (-INH group).
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PMID:Evidence for the action of bovine follicular fluid factor(s) other than inhibin in suppressing follicular development and delaying oestrus in heifers. 133 40

The low implantation rate after embryo transfer (ET) is the most important problem to be solved in in vitro fertilization and embryo transfer (IVF-ET). Various factors which may affect embryo implantation in the endometrium have been examined. In this study, the influence of the timing of luteinization on the establishment of pregnancy was investigated. Follicle stimulation was performed by luteinizing hormone-releasing hormone agonist, human menopausal gonadotropin and human chorionic gonadotropin (hCG). hCG was injected on the day when the mean diameter of two follicles exceeded 16 mm, and 36 h after the injection the oocyte was retrieved. Progesterone (P4) supplement was started on the day of ovum retrieval (50 mg), followed by 30 mg for 14 days. The patients were divided into three groups: (1) the pregnant patients (n = 20: group Pre); (2) the nonpregnant patients without bleeding during P4 injection (n = 35; group N), and (3) the nonpregnant patients with bleeding during P4 injection (n = 30; group B). The number of follicles that developed, endometrial thickness, the day of operation, the number of oocytes harvested, the number of good quality oocytes, the number of oocytes fertilized, the number of embryos transferred, estradiol (E2) and P4 levels, and the E2/P4 ratio were examined. The endometrial thickness of group Pre (10.9 +/- 0.6 mm; mean +/- SEM) on the day of hCG injection was significantly (p less than 0.05) greater than that of groups N (9.0 +/- 0.4 mm) and B (9.2 +/- 0.3 mm).(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Factors promoting embryo implantation in in vitro fertilization and embryo transfer. 142 32

Events in the normal menstrual cycle of the endangered Sulawesi Crested Black Macaque (Macaca nigra) were characterized. Daily blood samples were obtained during 10 menstrual cycles from five M. nigra demonstrating regular cycles. The amount of perineal tumescence was scored daily. Serum levels of estradiol and progesterone were determined by RIA, serum LH levels were determined by the mouse Leydig cell bioassay, and serum FSH levels were determined by the rat granulosa cell aromatase bioassay. Cycle length was 39.8 +/- 1.0 days (mean +/- SEM) with an LH surge occurring 25 +/- 1.5 days from the onset of menses. After menses, both LH and estradiol were initially depressed, with estradiol first exceeding 50 pg/ml 8 days before the LH surge. In five cycles, peak estradiol levels (340 +/- 44 pg/ml) occurred on the day of the LH surge (637 +/- 58 ng/ml) and in the other five cycles, on the day before the LH surge. There was a broad increase of FSH in midcycle without a well-defined surge corresponding to the LH surge. Progesterone began increasing on the day of the LH surge and reached peak levels (6.8 +/- 0.96 ng/ml) 8 days later. Maximal perineal tumescence was generally associated with the time of the LH surge, but variation between animals made it impossible to predict accurately the day of the LH surge by perineal tumescence scores alone.
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PMID:The Sulawesi Crested Black Macaque (Macaca nigra) menstrual cycle: changes in perineal tumescence and serum estradiol, progesterone, follicle-stimulating hormone, and luteinizing hormone levels. 159 42

While the regulation of progesterone secretion from the corpus luteum by LH has been convincingly demonstrated, the secretory patterns in the absence of any pituitary LH inputs are yet unclear. Consequently, we investigated the progesterone secretion by an in vitro perifusion system to characterize spontaneous progesterone release from the isolated bovine corpus luteum. Slices (120 mg) of midluteal corpora lutea were placed in perifusion chambers and continuously perifused by Medium-199 for 160-320 min. Progesterone was determined by radioimmunoassay in the effluent fractions collected at 2-min intervals. The spontaneous progesterone release from all bovine corpora lutea was pulsatile. Pulses were observed at mean (+/- SEM) intervals of 17.7 +/- 1.5 min with amplitudes of 6.7 +/- 0.5 ng and release rates of 29.5 +/- 2.4 ng.ml-1.(2 min)-1 (N = 5). Addition of 6.7 nmol/l hCG to the perifusion medium appeared to increase the pulse amplitudes and release rates (195 +/- 25% over unstimulated conditions), but did not change the pulse frequencies (N = 3). Perifusions with calcium-free medium containing 50 mumol/l verapamil and 20 mmol/l EGTA tended to suppress the pulse frequencies and amplitudes of this spontaneous progesterone release, whereas addition of hCG reversed this decrease again (N = 3). When prostaglandin activity was inhibited by 100 mumol/l indomethacin added to the perifusion medium, both pulse frequencies and amplitudes of this progesterone release were enhanced (N = 4). During perifusions with 100 mumol/l of the anti-progesterone ZK 96.734, both the pulse frequencies and amplitudes increased (N = 4). These studies demonstrate an episodic progesterone release from the bovine corpus luteum perifused in vitro.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Autonomous progesterone secretion from the bovine corpus luteum in vitro. 190 Jun 54

The purpose of this study was to analyze follicular fluid (FF) samples for steroid levels from stimulated and unstimulated cycles triggered with human chorionic gonadotropin (hCG) and to assess the influence of controlled ovarian hyperstimulation and luteinizing hormone/hCG on these levels. Spontaneous ovulatory cycles were monitored with serial ultrasound examinations, and hCG 10,000 IU was given when the lead follicle was mature. Fourteen FF samples yielding fertilizable oocytes were compared with 13 FF samples from controlled ovarian hyperstimulation cycles. Progesterone (P) was higher in controlled ovarian hyperstimulation than in unstimulated cycles (9.0 +/- 1.2 micrograms/mL versus 4.4 +/- 0.6 microgram/mL; mean +/- SEM), whereas estradiol (E2) was lower (0.8 +/- 0.1 microgram/mL versus 1.3 +/- 0.2 microgram/mL), resulting in a higher P:E2 ratio (15.5 +/- 3.3 versus 4.4 +/- 0.7). Androstenedione (A), testosterone (T), and T:E2 ratios were all higher in unstimulated than controlled ovarian hyperstimulation cycles. We conclude that controlled ovarian hyperstimulation is associated with increased FF P, decreased FF E2, T, and A levels, and decreased T:E2 ratios, suggesting altered steroidogenesis and enhanced follicular aromatase activity.
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PMID:Preovulatory follicular fluid steroid levels in stimulated and unstimulated cycles triggered with human chorionic gonadotropin. 198 71

Estrogens (estrone [E1] and estradiol [E2]), their sulfates and progesterone receptor (PR) were evaluated in patients with uterine leiomyomata nontreated and treated with Decapeptyl (D-Trp6-gonadotropin-releasing hormone [GnRH]; Ipsen Biotech, Paris, France). Estrogen concentrations are very high in the leiomyoma (secretory phase, pg/g tissue [mean +/- SEM]: n = 10; E1: 147 +/- 24; E2: 850 +/- 116; E1-sulfate: 1,668 +/- 808; E2-sulfate: 718 +/- 126). Decapeptyl treatment provokes a significant decrease in E2 and particularly in E1 and E2 sulfates. Progesterone receptors were higher in the leiomyoma than in the myometrium; after a long treatment (3 to 4 months) a significant decrease in both tissues is observed. The decrease provoked by D-Trp6-GnRH on estrogens (unconjugated and sulfates) and in PR in the leiomyoma after long treatment, supports the hypothesis that estrogens are implicated in the cause of these tumors.
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PMID:Effect of Decapeptyl, an agonistic analog of gonadotropin-releasing hormone on estrogens, estrogen sulfates, and progesterone receptors in leiomyoma and myometrium. 214 Sep 91

Progesterone and 5 alpha-pregnane-3,20-dione (5 alpha-DHP) concentrations were measured in seven brain areas and in plasma during "anesthesia" induced by progesterone (1-2 mg IV) in female rats. The highest levels of progesterone were detected in the striatum and hypothalamus (23.3 +/- 5.27 and 22.7 +/- 4.30 micrograms/g +/- SEM, respectively); these concentrations were approximately 1000 times higher than those during the post-ovulatory phase. Highest levels of 5 alpha-DHP were detected in the striatum and hippocampus (11.5 +/- 1.74 and 10.4 +/- 3.15 micrograms/g +/- SEM, respectively). The ratio of 5 alpha-DHP to progesterone was approximately 100 times higher in brain tissue than in plasma. We conclude that a conversion of progesterone to 5 alpha-DHP occurs in the brain during the course of progesterone-induced "anesthesia". This metabolic step may be an important contributory factor to the anesthetic potency of progesterone.
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PMID:Regional distribution of progesterone and 5 alpha-pregnane-3,20-dione in rat brain during progesterone-induced "anesthesia". 235 12


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