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Query: UNIPROT:P01178 (oxytocin)
 15,767 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Placental steroid sulfatase deficiency is an unusual cause of low estriol production during pregnancy. Its importance lies in the differentiation of this disorder from the more ominous fetal defects that result in low estriol levels. Serum free estriol levels were found to be low or absent in a 25-year-old gravida 3, para 2 woman, while placental lactogen and chorionic gonadotropin levels were normal. An abdominal x-ray revealed no apparent congenital abnormalities and an oxytocin challenge test was negative. The dehydroepiandrosterone sulfate (DHEA-S) level in the patient's amniotic fluid was 6.8 to 18.4 times greater than those found in control amniotic fluids. The patient's amniotic fluid cortisol level was normal. Twenty-four hours following a normal, spontaneous labor and delivery at 39 weeks, the male infant underwent a synthetic ACTH1-24 stimulation test, with serum cortisols rising from 3.7 to 46 mug/dl at 1 hour. The placenta was morphologically normal on gross, light, and electron microscopic examinations. Steroid 3-alcohol sulfatase and arylsulfatase activities in the patient's placenta were virtually absent. These data indicate that this benign cause of low serum estriol levels may be diagnosed prenatally by elevated amniotic fluid DHEA-S levels.
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PMID:Prenatal diagnosis of placental steroid sulfatase deficiency. 13

Contractile elements are found in the ovaries of many species, but it has not been possible to ascertain whether these elements are of importance in the process of ovulation. In this report, we describe changes in intraovarian pressure recorded continuously in vivo in unanesthetized rabbits under normal conditions and under the influence of intravenously injected human chorionic gonadotropin (hCG), as well as following the ovulatory stimulus of normal copulation. The recordings were made by means of small latex balloons (0.02- to 0.04-ml volume) attached to indwelling catheters, inserted into the ovarian stroma, and secured with 6-0 nylon sutures. All 24 rabbits studied showed changes in intraovarian pressure indicative of ovarian contractile activity. The intraovarian pressure changes followed a characteristic pattern which was different from the changes in intratubal pressure, recorded simultaneously from the lumen of the ipsilateral fallopian tube, indicating that the contractions of both organs occurred independently. In normal animals, before an ovulatory stimulus was applied, the ovarian contractility pattern consisted of a series of rapid contractions (average amplitude, 6 mm Hg; average frequency; 8 per minute) occurring with intervals of quiescence lasting from 11 to 36 minutes. The base line tonus was frequently elevated during these series of contractions. Mating or an injection of hCG had no immediate effect on intraovarian pressure but, 6 to 8 hours after the stimulus was applied, ovarian contractile activity increased significantly in all rabbits. This enhanced activity persisted for several hours before returning to initial levels approximately 15 to 18 hours after mating or the hCG injection. This demonstration of increased contractile activity about the time of ovulation suggests that ovarian contractions participate in the process of follicular rupture and the extrusion of ova at ovulation. Prostaglandin F2alpha, norepinephrine, and oxytocin were effective in inducing ovarian contractions.
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PMID:Intraovarian pressure changes during ovulation in rabbits. 94 31

Current approaches to control fertile estrus and parturition in the pig are discussed. Techniques to induce estrus in acylic pigs (pregnant mare serum gonadotropin and human chorionic gonadotropin) to synchronize estrus in cyclic females (progestins), and to control onset of ovulation (human chorionic gonadotropin) are described. Regimens that induce parturition (prostaglandins) and precipitate farrowings at more predictable times (oxytocin) are addressed.
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PMID:Pharmacologic control of swine reproduction. 144 78

In 1991, the abortion literature comprised articles on epidemiologic issues in abortion care advances in abortifacient such as mifepristone (RU-486) and cervical ripening prior to abortion with the use of both mifepristone and prostaglandins. A comprehensive analysis of American women having abortions indicated that although the overall abortion rate had declined since 1980, the rate of unintended pregnancies had remained the same since 1982. Among married, white women over age 30 and white, unmarried women in their twenties abortion rates declined. A prospective cohort study showed no overall differences in nonviable pregnancy outcome, birth weight, and length of gestation between 6188 women who had an abortion and 7073 who did not. In most developed countries prostaglandins are widely used for termination of pregnancy in the 2nd trimester, either as an intra-amniotic or extra-amniotic preparation. In a retrospective analysis, oxytocin was quite effective in achieving rapid, uncomplicated fetoplacental expulsion. It had a mean induction-to-delivery interval of 8.2 (+ or - 5.1) hours, which was significantly better than a mean induction-to-delivery interval of 13.1 (+ or - 7.8) hours in the group that had received prostaglandin E2 suppositories. The World Health Organization estimated that 22-56% of maternal mortality is directly attributable to abortion. In Enugu, Nigeria, the mortality rate from incomplete abortion amounted to 17.9%, and septicemia was documented in 49% of cases. Cervical pretreatment prior to a 2nd-trimester abortion has become standard in many institutions. In a double-blind, double-randomized trial both mifepristone and gemeprost resulted in a cervix that required less force to dilate to 9 mm (P 0.001). The gemeprost group had significantly more side effects than the mifepristone group. Mifepristone is a safe alternative for the termination of pregnancy when the beta human chorionic gonadotropin is below 20,000 IU/L. In spite of the small sample size (n = 50) and a rather high 12% rate of postabortal pelvic inflammatory disease, when the beta human chorionic gonadotropin decreased by at least 40% in the 1st week after receiving mifepristone, the abortion procedure was invariable complete.
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PMID:Abortion: epidemiology, safety, and technique. 150 70

Oxytocin is produced in the granulosa-derived cells of the ruminant corpus luteum where its gene is dramatically up-regulated within days of ovulation. Regulation of these processes is poorly understood but oxytocin release can be increased by insulin, insulin-like growth factor I (IGF-I), and gonadotropins. Here we have assessed interactions between these regulatory systems. Follicle-stimulating hormone (FSH), luteinizing hormone (LH) and human chorionic gonadotropin (hCG) caused dose-dependent release of oxytocin from bovine granulosa cells cultured in medium containing 100 ng/ml insulin. The gonadotropins also increased oxytocin mRNA levels and their effects were mimicked by forskolin. The effects of these stimuli on oxytocin and progesterone release were synergistically increased by insulin or IGF-I. Binding studies revealed separate binding sites with characteristics of insulin and IGF-I receptors. Insulin potentiated the effects of hCG and forskolin on oxytocin mRNA levels and release of oxytocin and progesterone in cells from follicles containing greater than 50 ng/ml estradiol. In cells from follicles containing less than 5 ng/ml estradiol these stimuli had little effect on oxytocin release although progesterone release was synergistically increased by insulin and forskolin. The data suggest that gonadotropins regulate oxytocin synthesis and release and that these effects are amplified by insulin or IGF-I acting via their own receptors. Changes associated with maturation of the target cells in vitro appear prerequisite for oxytocin production in response to increased cAMP levels in the presence of insulin or IGF-I.
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PMID:Effects of gonadotropins, insulin and insulin-like growth factor I on ovarian oxytocin and progesterone production. 166 78

Treatment of cattle during the middle of the luteal phase with appropriate doses of human chorionic gonadotropin (hCG) causes a 5 d extension of the estrous cycle. Three experiments were conducted to determine how treatment with hCG affected the pattern of secretion of prostaglandin F2 alpha, as indicated by blood levels of 13,14-dihydro-15-keto-prostaglandin F2 alpha (PGFM). In experiment 1, Holstein cows were given saline (Sal) or hCG (10,000 IU, im) on d 10 of the estrous cycle and blood samples were collected over a 6 h period on d 14 and 18 during which oxytocin (10 and 100 IU, iv) was given at 2 and 4 h. Concentrations of PGFM before and after oxytocin were similar between Sal and hCG-cycles, but PGFM was higher on d 18 than d 14 (P less than 0.05). In experiment 2, episodic PGFM was measured from d 16 to 20 in cows given Sal or hCG on d 10. There was tendency for hCG to reduce PGFM baseline and pulse amplitude (P = 0.22). In experiments 1 and 2, estradiol increased during d 16 to 20 of Sal-cycles, but did not change during this period of hCG-cycles. Therefore, in experiment 3, Holstein heifers were given Sal or hCG (5000 IU, im) on d 10, followed by corn oil (Oil) or estradiol benzoate (EB; 200 micrograms, im, 2X/day) on d 15 to 18. No difference in progesterone secretion was observed between Sal-Oil and Sal-EB heifers; however, EB hastened luteolysis in hCG-treated heifers (P less than 0.05), without causing an increase in PGFM. Although subtle differences were seen in pulsatile PGFM, we conclude that hCG altered the pattern of estrogen secretion, and this led to delayed luteolysis.
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PMID:Associations among progesterone, estradiol-17 beta, oxytocin and prostaglandin in cattle treated with hCG during diestrus to extend corpus luteum function. 238 60

Expanded use of artificial insemination in the beef cattle industry depends on successful application of treatments designed to synchronize estrus. Regulation of estrous cycles is associated with control of the corpus luteum (CL), whose life span and secretory activity are subject to trophic and lytic mechanisms. The advantages of melengestrol acetate (MGA) in estrous synchronization incorporate ease of administration, lower cost relative to other estrous synchronization products, and potential for use to induce estrus in prepubertal heifers. Treatments first designed to synchronize estrous cycles of normally cycling heifers by feeding MGA were imposed daily for 14 to 18 d at levels of .5 to 1 mg. The minimal daily effective dose required to inhibit ovulation was .42 mg. Longer feeding periods of MGA were associated with low fertility at the first synchronized estrus, but at the second estrus, conception was normal. Low fertility at the synchronized estrus resulted in development of alternative treatment practices, which combined feeding of MGA with injections or implants of estradiol-17 beta, estradiol cypionate, luteinizing hormone, human chorionic gonadotropin, pregnant mare serum gonadotropin, or oxytocin. Estrus was synchronized after MGA and estradiol-17 beta or estradiol cypionate treatments, but fertility was low. Short-term feeding of MGA (5 to 7 d) combined with prostaglandin F2 alpha or its analogs (PGF) on the last day of MGA reduced fertility at the synchronized estrus. The reduced conception at first service occurred in animals that began treatment after d 12 of the estrous cycle. However, feeding MGA for 14 d and then injecting PGF 17 d later avoided problems with reduced conception. Fertility of animals after this treatment was similar to that of contemporaries synchronized with Syncro-Mate-B. However, the length of the treatment period creates a need for increased management and may extend management beyond practical limits. Further research is warranted to address problems associated with reduced fertility after short-term treatment with MGA.
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PMID:Control of the bovine estrous cycle with melengestrol acetate (MGA): a review. 267 33

The number of cases of hydatidiform mole (HM) registered annually in England and Wales has risen since 1973 to 1.54 per 1000 live births in 1983. For women over 50 the risk per pregnancy was 411 times and for girls under 15 it was six times greater than that for women aged 25-29. 7.75% of patients had chemotherapy for invasive mole or choriocarcinoma. Patients who had had oxytocin-induced or prostaglandin-induced uterine evacuation or hysterotomy were more likely to need chemotherapy. Human chorionic gonadotropin (HCG) was undetectable by 56 days after evacuation in 42% of patients, none of whom required chemotherapy; a considerable reduction in follow-up time for this subgroup is proposed. For patients whose HCG values became normal more than 56 days after evacuation and stayed normal for 6 months the risk of recrudescent disease was 1 in 286. In subsequent pregnancies the risk of a second HM was 1 in 76 and that of a third was 1 in 6.5. 11 (0.2%) patients died, 2 from drug-resistant choriocarcinoma.
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PMID:Hydatidiform mole in England and Wales 1973-83. 287 45

From each of 43 women who had gynecologic laparotomy at different and well-classified stages of the luteal phase of the cycle, the corpus luteum (CL) was excised, cut into pieces, and incubated for short time periods (30 to 240 minutes). Incubations were performed in the absence and presence of human chorionic gonadotropin (hCG) and different concentrations of oxytocin ([OT], 0.1 to 1000 mIU/ml). After incubation, the tissue levels of cyclic adenosine 3',5'-monophosphate (cAMP) and the media concentrations of progesterone (P) were determined. Although hCG stimulated both cAMP and P formation in CL of all ages, OT alone had no effect on the basal production of these parameters. However, under certain experimental conditions, OT counteracted the stimulatory effect of hCG on both cAMP and P formation. Because the maximal antigonadotropic effect was found for concentrations of OT in the magnitude of the physiologic intraluteal concentration, these in vitro data suggest a role for OT in the luteolytic process of humans.
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PMID:Antigonadotropic effect of oxytocin on the isolated human corpus luteum. 303 Aug 27

The release of relaxin from cultured porcine luteal cells derived from pregnant sows was detected by a reverse hemolytic plaque assay. In this assay, luteal cells are cocultured in monolayers with protein-A-coupled ovine erythrocytes. In the presence of porcine relaxin antiserum and complement, a zone of hemolysis--a plaque--develops around relaxin-releasing luteal cells. Treatment with prostaglandin E2 (10(-8) and 10(-6) M) significantly accelerated the rate of plaque formation; in contrast, human chorionic gonadotropin (10-1,000 IU/ml) inhibited the rate of plaque formation. Oxytocin (10(-8) to 10(-4) M) had no detectable effect on relaxin release. However, none of these treatments or long-term preexposure to prostaglandin F2 alpha increased the total proportion of large luteal cells that released relaxin, which remained at about 50%. These results are consistent with the idea that prostaglandins of uterine and/or luteal origin and pituitary luteinizing hormone may contribute, alone or perhaps in combination, to the overall regulation of ovarian relaxin release during pregnancy in the sow. In addition, the results indicate that the effects of prostaglandins are restricted to a subpopulation of large luteal cells that release detectable amounts of relaxin in culture.
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PMID:Detection of relaxin release by porcine luteal cells using a reverse hemolytic plaque assay: effect of prostaglandins E2 and F2 alpha, human chorionic gonadotropin, and oxytocin. 331 14


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