PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “CORPUS LUTEUM HORMONES”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 55 records · Page 3Linked to original sources
PubMed1999

The effects of growth hormone on corpus luteum of superovulated rats.

In general, growth hormone acts as a factor promoting cell proliferation in the positive direction and suppresses apoptosis. No report has described growth hormone (GH)-induced structural luteolysis. The present studies showed that GH induced structural luteolysis in rats after the induction of functional luteolysis by treatment with bromocriptine, and that apoptotic cells were present among luteal cells during structural luteolysis as shown by terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling. Zymography showed that the activity of matrix metalloproteinase (MMP)-2 increased during GH-induced structural luteolysis. The expression of c-myc protein of luteal cells was significantly decreased, but proliferating cell nuclear antigens (PCNA) were conversely increased during structural luteolysis, as shown by Western blot analysis. We propose that an excessive increase in PCNA and a marked decrease in c-myc protein of luteal cells lead to a disorder in the signals concerned with DNA synthesis, causing mitotic catastrophe and inducing apoptosis in luteal cells, and that structural luteolysis may be triggered. GH-induced apoptosis in structural luteolysis therefore highly depends on the cell cycle. There are thought to be two mechanisms of GH-induced structural luteolysis. One is apoptosis, and the other is destruction of extracellular matrix by MMP.

20-alpha-Dihydroprogesterone↗
PubMed1980

Ovarian follicular and luteal physiology.

Follicular maturation and development is a complex process of interrelated intra- and extraovarian events that ultimately lead to ovulation of a mature oocyte and transformation of the ruptured follicle into a corpus luteum. The primordial follicle consists of an immature oocyte arrested in the dictyate stage of meiosis, surrounded by a single layer of relatively undifferentiated granulosa cells. The oocyte remains in the immature state because of many factors, one of which is the oocyte maturation inhibitor (OMI) secreted by granulosa cells. The oocyte subsequently increases in size, and as the antrum forms it becomes surrounded by cumulus cells. The cumulus cells may be intimately involved in the action of O,I to arrest the oocyte in the immature state within the follicle, as well as the resumption of meiosis during the LH surge. The compartments of the follicle that change most dramatically during follicular maturation are the cells lining the follicle--the granulosa and thecal cells. Under the influence of estrogen and FSH, the granulosa cells proliferate and also acquire FSH receptors. At this time, the thecal compartment differentiates and surrounds the granulosa cells, but remains separated from them by a basement membrane. Steroid secretion by the antral follicle involves the interplay of androgens, estrogens, and progestins. Both the granulosa and thecal cell compartments contribute to follicular fluid and serum levels of steroids; the interaction of both cell types may be necessary for estrogen and progesterone secretion in some species. As a consequence of the presence of an elevated number of FSH receptors, the granulosa cells of the small antral follicle are able to respond to FSH in many ways, including increased cyclic AMP accumulation, activation of the aromatase system, and induction of LH receptors, which permits the granulosa cells to later respond to LH. The mechanism by which thecal cells acquire their LH receptors is presently unknown. The granulosa cells of the follicle may indirectly control their own maturation and the number of follicles maturing through the secretion of follicular inhibin, which decreases the pituitary output of FSH. Even though the granulosa cells have acquired large numbers of LH receptors, they are prevented from luteinizing prematurely by factors in follicular fluid, including estrogen and a luteinizing inhibitor (LI). As serum LH levels increase during the preovulatory LH surge, a number of events occur: resumption of oocyte meiosis, transformation of the steroid enzyme complex from estrogen to progesterone secretion, follicular rupture, and formation of the corpus luteum. Granulosa cells form the bulk of the corpus luteum, which secretes elevated amounts of progesterone for a fixed time period depending on the species. Before ovulation the preovulatory follicle must be exposed to and respond to adequate LH and FSH levels in order for the eventual corpus luteum to secrete elevated amounts of progesterone for its normal lifespan...

Animals↗
PubMed1982

The pattern of luteal phase plasma progesterone and estradiol in fertile cycles.

Serum levels of progesterone and estradiol at early, middle, and late luteal phases were compared in nonfertile cycles in which only ovulation occurred to those in cycles in which ovulation was verified by conception. Two groups of patients were studied: 33 normal ovulatory women (12 of whom conceived) and 28 women who underwent induction of ovulation (8 of whom conceived). In each group, mean midluteal levels of progesterone and estradiol were essentially similar in nonfertile and fertile cycles. In fertile cycles, the late luteal levels of both steroids were higher than their respective midluteal values, whereas the late luteal values dropped in the nonfertile cycles. The late luteal rise in estradiol was found to be a more sensitive indicator of pregnancy than that of progesterone. The progesterone/estradiol ratio was stable during the luteal phase of fertile and nonfertile cycles. The ratio in spontaneous cycles was 34.4 +/- 4.7 and only 17.9 +/- 4.3 in induced cycles. This marked decrease suggests an impairment of steroid metabolism in women who require induction of ovulation.

Adult↗
PubMed1992

Superoxide dismutase activity, lipid peroxide production and corpus luteum steroidogenesis during natural luteolysis and regression induced by oestradiol deprivation of the ovary in pseudopregnant rabbits.

The relationship of oxygen free radicals to corpus luteum function in rabbits was explored during various stages of pseudopregnancy, including natural and induced luteal regression. Induced luteolysis was achieved during mid-pseudopregnancy by removal of an oestradiol capsule placed at the onset of pseudopregnancy, which suppressed ovarian oestradiol production. Activity of manganese superoxide dismutase (Mn SOD) was significantly and positively correlated with ovarian progesterone production (P < 0.01) throughout pseudopregnancy and during natural regression. Oestradiol deprivation for 12, 24 or 72 h resulted in declines in Mn SOD activity and progesterone secretion, although Mn SOD rose and corpus luteum steroidogenesis was restored to normal when the capsule was replaced for 48 h before assessment, having been removed for 24 h. Lipid peroxide and progesterone concentrations were not correlated, although a significant rise in lipid peroxides in the luteal tissue was detected after deprivation of oestradiol for 72 h. Changes in progesterone production and Mn SOD activity were not associated with alterations in concentration of prostaglandin F metabolite. These data suggest that Mn SOD may be involved in regulating function of the corpus luteum during pseudopregnancy in rabbits and that oxygen free radicals may play a role in regression of corpus luteum in this species.

Animals↗
PubMed1979

Effects of immunization with the beta-subunit of ovine luteinizing hormone on corpus luteum function in the rhesus monkey.

Rhesus monkeys immunized with the beta-subunit of ovine luteinizing hormone (oLHbeta) developed circulating antibodies which cross-reacted strongly with rhesus monkey chorionic gonadotropin. Normal ovulatory cycles continued, but the fertility of immunized monkeys as compared with that of controls was significantly reduced. Thus, the rhesus monkey represented a useful animal model for the study of certain aspects of an "antifertility vaccine." We investigated the effects of circulating antibodies to oLHbeta on corpus luteum function by measuring production rates (PRs) and peripheral concentrations of progesterone during the luteal phase of the menstrual cycle. Both parameters were significantly lower in immunized animals than in control animals. The length of the menstrual cycle was also significantly reduced. Progesterone PRs were also determined on days 10 and 15 after mating to test the assumption that the antifertility vaccine prevents pregnancy by interfering with "corpus luteum rescue" (the increase in PRs of progesterone usually occurring on day 15 after mating in fertilized animals). PRs increased from days 10 to 15 in pregnant controls, were unchanged in nonpregnant controls, and were significantly lower on day 15 in immunized monkeys as compared with nonpregnant and pregnant controls. These results suggest that "corpus luteum rescue" is suppressed in immunized animals.

Animals↗
PubMed1984

Effects of neutralization of luteinizing hormone on corpus luteum function and cyclicity in Macaca fascicularis.

The primate corpus luteum (including the human) is thought to require continuous exposure to LH for normal progesterone production and menstrual cyclicity. Recently, normal luteal function was reported in rhesus monkeys after postovulatory hypophysectomy or treatment with an antagonist to GnRH. We studied the effects of neutralization of LH by specific antiserum in the fascicularis monkey. A potent antiserum to ovine LH, which cross-reacted with monkey pituitary extract, was produced in rabbits; this antiserum was administered daily to cycling monkeys during the midluteal phase. The pretreatment cycle duration was 32.4 +/- 1.7 (+/- SE) days, and luteal length was 16.5 +/- 0.8 days, with a midluteal progestin peak of 15.28 +/- 2.23 ng/ml. LH antiserum treatment resulted in a precipitous fall in serum progestin within 24 h, which remained low for the remainder of the cycle. All treated monkeys had premature menstrual bleeding, with mean cycle length shortened to 22.8 +/- 1.6 days (P less than 0.0005). These results confirm that the continuous presence of LH is essential for maintenance of corpus luteum function in this species of primate.

Animals↗
PubMed2000

[Role of luteinizing hormone in follicular and corpus luteum physiology].

Luteinizing hormone (LH) is an hypophyseal glycoprotein involved in both follicular maturation and corpus luteum function. During the follicular phase, effects of LH must be considered according to the stages of follicular development: in the early follicular phase, LH acts through specific receptors, constitutively present on thecal cells, for stimulating androgen production. Androgens seem to be positively involved in the folliculogenesis in primates. Indeed, a positive correlation has been recently established between androgen receptor expression and follicular cell proliferation. Furthermore, androgens are active through a conversion to estrogens in granulosa cells. Estrogens are needed for achieving pregnancy. Thus, a question remains: what in the minimal amount of endogenous LH required for an optimal production of oestradiol? Several models have been investigated in clinical situations with hypogonadotrophic hypogonadism: WHO type I anovulation or GnRH analog-induced hypogonadisms. A large majority of these studies conclude that the minimal amount of LH needed during the follicular phase is probably low (< 1.5 IU/L of plasma LH level). Recent availability of GnRH antagonist will give a new opportunity for evaluating this minimal LH threshold. During the late follicular phase, LH plays a biphasic role, with a positive effect on steroidogenesis but a negative effect on cell proliferation. As suggested by S. Hillier, this negative effect on cell proliferation may be relevant to control the rate of follicular growth. One study, performed in WHO type I anovulatory patients, seems to confirm this assumption but further evaluation is needed to give support to this concept. Finally, LH is also involved in corpus luteum function. Due to the short half-life of LH as compared to hCG, the role of LH must be evaluated according to the adjunct therapies. For example, following a long-term GnRH aganist administration that constantly induces a profound hypophyseal desensitization, LH administration must be repeated to adequately sustain the corpus luteum function. This conclusion must be reconsidered with the recent introduction of GnRH antagonists. Indeed, according to their short-term effects on LH secretion, it may be presumed that a single injection of LH may be effective to maintain an adequate corpus luteum function.

Animals↗
PubMed1994

Particulate binding sites for steroid hormones in subcellular fractions of the ovine corpus luteum: properties and hormone specificity.

We have described previously the presence of binding sites in particulate fractions of the porcine corpus luteum (CL) which were specific for progesterone. We now demonstrate the presence of similar progesterone-specific binding sites in particulate fractions of the ovine CL. Preincubation of ovine luteal membranes with radiolabelled steroids demonstrated binding of progesterone and pregnenolone to a low-density particulate fraction (1.07-1.09 g/cm3). Preincubation with digitonin perturbed the buoyant density of this fraction (to 1.10-1.14 g/cm3) without causing release of steroid. Androgens and oestrogens did not bind appreciably to control luteal membranes, but were bound when preincubated with digitonin. In contrast, steroid conjugates (oestrone sulfate, pregnanediol glucuronide), cortisol, fatty acids (arachidonic acid, prostaglandin F2 alpha) and cholesterol ester failed to bind to ovine luteal membranes, with or without digitonin pretreatment. The effects of digitonin on steroid binding led us to examine its effects on steroid binding to ovine luteal membrane fractions in vitro. Specific progesterone binding was absent in the absence of digitonin, even at very high membrane concentrations. However, binding of 3H-labelled progesterone was stimulated 5-15-fold in a dose-dependent fashion by increasing digitonin concentrations, reaching a plateau at about 100 microM. In the presence of digitonin, [3H]progesterone binding increased linearly with luteal membrane concentration. Other detergents, saponins and cardiotonic steroids tested did not stimulate progesterone binding to ovine luteal membranes. [3H]Progesterone binding was dependent on the pH, duration and temperature of incubation. Unlabelled progesterone decreased binding of [3H]progesterone (half-maximal displacement of specific binding (IC50) at about 60 nM) whereas androgens were less potent (IC50, 500-3300 nM), whilst a wide range of other steroids and inhibitors of steroidogenic enzymes were ineffective, except at very high concentrations. Similarly, a number of progesterone receptor agonist and antagonist analogues failed to compete for progesterone binding to luteal membranes, suggesting that these binding sites were unrelated to progesterone receptors. Modifications to the 3, 4, 5 and 11 positions of progesterone, removal of the steroid side-chain or aromatization of the A-ring decreased binding potency dramatically, whereas changes to the 17 or 20 positions had relatively minor effects. Our results indicate the presence of a low density particulate fraction in ovine corpora lutea which contains specific binding sites for endogenous and exogenous progesterone.

Androgens↗
PubMed1993

Norgestomet and gonadotropin-releasing hormone enhance corpus luteum function and fertility of postpartum suckled beef cows.

In Exp. 1,101 suckled beef cows were administered two injections of prostaglandin F2 alpha (PGF2 alpha) 11 d apart. Cows in Group 1 received no additional treatment. Cows in Groups 2 and 3 received 250 micrograms of GnRH plus 47-h calf removal. Cows in Group 3 also received a norgestomet ear implant that was inserted 4 d after the first PGF2 alpha injection and left in situ for 8 d. The second PGF2 alpha injection was administered approximately 28 h before the time of norgestomet implant removal. The GnRH was administered approximately 30 h after the time of norgestomet implant removal (or 58 h after the second PGF2 alpha injection). Calf removal was the period from the time of implant removal to AI. All cows were artificially inseminated once 75 h after the second PGF2 alpha injection (47 h after implant removal). Reproductive status before the time of GnRH treatment (presynchronization) was determined by multiple sampling (2, 13, and 23 d before GnRH treatment) for blood progesterone concentrations (62% anestrous and 38% cyclic). The GnRH treatment increased (P < .01) the ovulation response and norgestomet reduced (P < .01) the incidence of short luteal phases in the presynchronization anestrous cows. Norgestomet treatment increased (P < .05) the timed breeding pregnancy rates for both presynchronization anestrous and cyclic cows. In Exp. 2, 174 suckled beef cows were administered Syncro-Mate B (which includes norgestomet). Cows in Group 1 received no additional treatment, whereas cows in Group 2 received 250 micrograms of GnRH (30 h after norgestomet implant removal).(ABSTRACT TRUNCATED AT 250 WORDS)

Anestrus↗
PubMed1989

Human corpus luteum: luteinizing hormone and chorionic gonadotropin receptors during the menstrual cycle.

To characterize and determine the concentration of LH/hCG receptors in human corpora lutea of the menstrual cycle, we measured occupied and unoccupied receptors and determined the association (Ka) and dissociation (Kd) constants individually in 23 corpora lutea (CL) and 4 corpora albicantia obtained at the time of tubal ligation from 25 normal cycling women. We found no [125I]hCG binding in any of the corpora albicantia. Scatchard plot analysis for each CL revealed a linear binding plot indicative of a single set of LH/hCG receptors. The mean concentration of unoccupied receptors was 36 +/- 10 (+/- SE) fmol/mg protein in the early luteal phase (days 15-19; n = 5), 64 +/- 11 fmol/mg protein in the midluteal phase (days 20-25; n = 13), and 42 +/- 19 fmol/mg protein in the late luteal phase (days 26-30; n = 5). The concentrations of occupied receptors were 56 +/- 8, 46 +/- 6, and 54 +/- 12 fmol/mg protein in the early, mid-, and late luteal phases, respectively. Total (occupied plus unoccupied) receptor concentrations reached maximum levels of 110 +/- 11 fmol/mg protein in the midluteal phase. Ka increased progressively from 12 +/- 4 X 10(9) mol/L-1 in the early luteal phase to 19 +/- 7 X 10(9) and 21 +/- 8 X 10(9) mol/L-1 in the mid- and late luteal phases. We conclude that in normal CL, 1) total and unoccupied LH/hCG receptor levels parallel progesterone secretion; 2) changes in the binding affinity may be important in sustaining and/or rescuing the CL; and 3) loss of LH/hCG receptors is probably related to luteolysis.

Adult↗