Follicle-stimulating Hormone-releasing Hormone Research Articles

Long-Term Efficacy and Reproductive Behavior Associated with GonaCon Use in White-Tailed Deer (Odocoileus virginianus)

GonaConTM is a single-shot immunocontraceptive vaccine that targets the reproductive hormone gonadotropin releasing hormone (GnRH). The GnRH peptide used in the vaccine is secreted by the hypothalamus of the brain and is specifically known as luteinizing hormone releasing hormone. This peptide stimulates the synthesis and secretion of luteinizing hormone and follicle stimulating hormone by the anterior pituitary gland. These hormones in turn stimulate hormone and gamete production by the ovary. In earlier studies with deer, we showed that antibodies produced in response to a single shot of GonaCon inactivated endogenous GnRH and greatly reduced fertility, reproductive steroids, and associated behaviors for at least 2 years. In the present study, we report on contraceptive efficacy and behavioral observations up to 6 years after female white-tailed deer were given a single shot of one of several formulations of GonaCon. We compared the standard GonaCon made by conjugating the GNRH peptide to keyhole limpet hemocyanin (GonaCon-KLH) to one with the GnRH peptide conjugated to a blue mollusk protein (GonaCon-Blue) and to a 2-shot regimen with GonaCon-KLH. All GonaCon preparations were made into an emulsion with AdjuVacTM and administered to 5 mature female deer per treatment. The results showed that the GonaCon-Blue preparation significantly out-performed the other single-shot vaccines, as well as the 2-shot regimen of GonaCon-KLH, with efficacy of 80-100% for each of the 5 years in the study. Interestingly, expression of estrous behavior was minimal in Years 1-2 following treatment for all groups, but expression of estrus increased in later years of the study, even though does remained infertile. This expression of estrus and fertility was reversed with follicle stimulating hormone releasing hormone (FSH-RH) peptide conjugated to a mollusk protein and mixed as an emulsion with AdjuVac. This suggests that does possess an FSH-RH peptide, secreted by the hypothalamus, which modulates follicle development and resulting estrogen production and reproductive behavior.

Hypothalamic control of gonadotropin secretion

Publisher Summary This chapter discusses the hypothalamic control of gonadotropin secretion. The control of gonadotropin secretion is extremely complex as revealed by the research of the past 40 years since the discovery of luteinizing hormone releasing hormone (LHRH), commonly called gonadotropin-releasing hormone (GnRH). This was the second of the hypothalamic-releasing hormones characterized. It stimulates follicle-stimulating hormone (FSH) release, albeit in smaller amounts than luteinizing hormone (LH). For this reason, it was renamed GnRH. Overwhelming evidence indicates that there is a separate follicle-stimulating hormone releasing hormone (FSHRH) because pulsatile release of LH and FSH can be dissociated. In the castrated male rat, roughly half of the FSH pulses occur in the absence of LH pulses, and only a small fraction of the pulses of both gonadotropins are coincident. The hypothalamic areas controlling LH and FSH are separable. Stimulation in the dorsal medial anterior hypothalamic area causes selective FSH release, whereas lesions in this area selectively suppress the pulses of FSH and not LH. Conversely, stimulations or lesions in the medial preoptic region can augment or suppress LH release respectively without affecting FSH release. The putative FSHRH is synthesized in neurons with perikarya in the dorsal anterior hypothalamic area with axons that project to the mid and caudal median eminence to control FSH release selectively.

Decapeptides as effective agonists from L-amino acids biologically equivalent to the luteinizing hormone-releasing hormone.

Apparently, no agonist has been found that is comparable in potency to the luteinizing hormone-releasing hormone (LHRH) for release of LH and follicle-stimulating hormone (FSH) without substitutions with unnatural or D forms of natural amino acids. Of 139 known "agonist analogs" of LHRH, two were active in the range of 65%. The four LHRHs known to occur in nature involve a total of six amino acids (Tyr, His, Leu, Trp, Arg, Gln) in positions 5, 7, and 8. There are 16 possible peptides with these six amino acids in positions 5, 7, and 8, of which 4 are the known LHRHs, and 2 more were synthesized. We have synthesized the 10 new peptides and assayed 11 in vivo and in vitro, and we found not only 1 but a total of 5 that have activity equivalent to or greater than that of LHRH for the release of LH and/or FSH under at least one assay condition. These five are as follows: [His5,Trp7,Gln8]LHRH; [His5,Trp7,Leu8]LHRH; [His5,Trp7]LHRH; [Trp7]LHRH; [His5]LHRH. Two of these five agonists variably released relatively more FSH than LH. One or more of these five agonists may occur in nature and one may be follicle-stimulating hormone-releasing hormone. The two peptides with Gln8 and Leu8, if occurring in nature, may have different receptors according to radioreceptor assays and to the ratio of LH/FSH release in vivo. These structures are a basis for the design of antagonists without Arg8 toward avoiding histamine release. Complete inhibition of LH and FSH release in vivo may be induced by joint use of Arg8 and Gln8 or Leu8 antagonists. These potent agonists, related to LHRH, may be therapeutically useful in disorders of reproduction, the central nervous system, and for the control of hormone-dependent carcinomas.

Studies on the follicle stimulating hormone releasing hormone by radioimmunoassays and by bioassays

An entity (in fractions), separated from the luteinizing hormone-releasing hormone (LHRH), <Glu-OH, and N-Ac-Asp-OH, which released both FSH and LH appeared to show immunoreactivity in the RIA for LHRH. This entity was destroyed by trypsin, but did not yield LHRH, under conditions which (1) converted a synthetic model, [Arg-Lys-Gln 1]-LHRH, of a pro-LHRH to LHRH; (2) did not destroy LHRH. This entity may not be a pro-LHRH, but may be the follicle stimulating hormone-releasing hormone (FSHRH) on the basis of all these data. A second immunoreactive entity had negligible, if any, releasing activity for FSH and LH, and did not yield LHRH on trypsin digestion.

Further Evidence that Luteinizing Hormone-Releasing Hormone also Is Follicle-Stimulating Hormone-Releasing Hormone*

While LHRH evokes the release of both LH and FSH under a wide spectrum of experimental conditions, this hormone has not been shown to induce the discharge of FSH unaccompanied by LH release. As a consequence, the possibility that a separate FSHRH exists has not been discounted. These experiments were designed to demonstrate that LHRH is capable of promoting marked increases in plasma FSH concomitant with physiologically insignificant changes in plasma LH and, thus, that LHRH is also FSHRH. Seven groups of cyclic female rats received phenobarbital at 1200 h proestrus to block spontaneous preovulatory LH and FSH surges. These various groups then were subdivided according to whether phosphate-buffered saline (PBS), LHRH, or both was infused (iv). The experimental protocol consisted of infusing material for an initial 30 min (priming period), stopping the infusion for 30 min (rest interval), and again infusing material for an additional 210 min (maintenance period). When PBS was infused during the priming and...

Differential Effects of the Pineal Gland on LH-RH and FSH-RH Activity in the Medial Basal Hypothalamus of the Male Golden Hamster

Crude neutralized acid extracts were made of medial basal hypothalamic (MBH) tissue obtained from adult male hamsters which had been either blinded, blinded and pinealec-tomized or left intact. After 11 weeks of treatment, the reproductive organs of the blind animals were markedly involuted compared to intact controls, an effect completely reversed by pinealectomy. The luteinizing hormone-releasing hormone (LH-RH) and follicle-stimulating hormone-releasing hormone (FSH-RH) activity of the extracts was assessed using an <i>in vitro</i> system in which LH and FSH release into the medium from hemipituitaries, derived from ovariectomized, estrogen-progesterone-treated female rats, was measured by radioimmuno-assay (RIA). LH and FSH release was responsive to synthetic LH-RH in a dose-related manner; however, in the latter case there were no statistically significant differences between the FSH responses to the various doses of LH-RH. The LH-RH activity of hypothalamic extracts from blind hamsters was depressed as compared with intact controls; however, this effect was not reversed by pinealectomy. The FSH-RH activity of hypothalamic extract from blind hamsters was virtually eliminated compared with that in hypothalami of intact controls. Unlike with LH-RH activity, pinealectomy completely reversed the effects of light deprivation on FSH-RH activity with levels returning to normal. These results indicate that the pineal gland of the male hamster is capable of influencing the hypothalamic levels of FSH-RH activity independent of LH-RH activity.

Some notes on the background of the isolation, determination of structure, synthesis, and early clinical trials of the luteinizing hormone- and follicle-stimulating hormone-releasing hormone

Some notes on the background of the isolation determination of structure synthesis and early clinical trials of the luteinizing hormone (LH)- and follicle stimulating hormone-releasing hormone (FSH-RH) are presented. The solving of the thyrotropin releasing hormone structure made the work on the hypothalamus easier. After establishing that the 11 types of estrogen-progesterone combinations used in contraceptive pills did not suppress the stimulatory effects of LH-RH on the release of LH it was postulated that contraceptive steroids act mainly on the hypothalamus. And later it was shown that these steroids also act on the pituitary gland. This helped postulate that sex steroids may cause differential release of LH and FSH in response to LH-RH/FSH-RH. Immunologic studies led to the production of antisera to LH-RH and development of a radioimmunoassay for LH-RH. It was then shown that such antisera caused gonadal atrophy in male animals and blocked the release of LH and FSH and ovulation in cycling rats. The synthesis of various analogs of LH-RH enabled 2 classes of these compounds to be established: 1) stimulatory superactive analogs causing prolonged liberation of LH and FSH and 2) inhibitory analogs which block LH and FSH release and ovulation.

Luteinizing Hormone-Releasing Hormone for Induction of Follicular Maturation and Ovulation in Women with Infertility and Amenorrhea

Five patients with primary infertility and secondary amenorrhea who did not respond to clomiphene with a gonadotropin or estrogen surge were treated with 500 mug of luteinizing hormone, follicle-stimulating hormone-releasing hormone (LH-RH), self-administered subcutaneously every 8 hours for 14 days. Of four patients who responded to this treatment, three showed follicular maturation, ovulation, and menses, although the luteal phase was deficient; in the fourth patient, follicular maturation and menses occurred without evidence of ovulation. For their second course of treatment these four patients were given LH-RH with the addition of human chorionic gonadotropin when the urinary estrogen levels indicated follicular maturation. All four patients responded with ovulation, an adequate luteal phase, and menses, without clinical indication of ovarian hyperstimulation. These results suggest that LH-RH may be a better alternative to human menopausal gonadotropin in the treatment of anovulatory infertility.

Re-examination of porcine and bovine hypothalamic fractions for additional luteinizing hormone and follicle stimulating hormone-releasing activities.

More than 150 hypothalamic fractions were reassayed for luteinizing hormone-releasing hormone (LHRH) and follicle stimulating hormone-releasing hormone (FSHRH) activities in search for LHRH and FSHRH which differ from the decapeptide (pyro)Glu-His-Trp-Ser-Try-Gly-Leu-Arg-Pro-Gly-NH2 (I). Among the porcine fractions tested were those obtained: 1) from the isolation of thyrotropin-releasing hormone; 2) from two isolation procedures for LHRH; and 3) from methanolic and aqueous 2N acetic acid extracts which were subjected to Biogel P-2 filtration and partition chromatography. Some bovine hypothalamic fractions were also tested. Both in vivo and in vitro assays were used for measuring LHRH and FSHRH activities. The values obtained were in each case compared with those resulting from the administration of pure natural or synthetic LHRH decapeptide I. A radioimmunoassay for LHRH (I) was also utilized for some fractions. In all the purification steps the location of LHRH and FSHRH activity, as determined by in vivo assays, corresponded to that of the decapeptide I. Purification of hypothalamic extracts on Biogel P-2 and by partition chromatography separated a fraction from the decapeptide I, which released more FSH than LH in vitro from the pituitaries of immature female rats. However, this material was inactive in vivo and in other in vitro systems, so that its significance is obscure. The results suggest that if material with LHRH and FSHRH activity other than the decapeptide I is present in acid extracts of porcine hypothalami, then its FSHRH and LHRH activity would be a minor part of the total LHRH/FSHRH activity in the extracts. (Pyro)-Glu-His-Trp-Ser-Tyr-Gly-Leu-Arg-Pro-Gly-NH2 appears to account for most of all of the LHRH and FSHRH activity found.

Factor C-LHIH which inhibits the luteinizing hormone from basal release and from synthetic LHRH and studies on purification of FSHRH

Data on a new entity which inhibits the release of luteinizing hormone (LH), designated as factor C-LHIH, are presented. In vitro assays were carried out with pituitary glands from female rats. Factor C-LHIH and follicle stimulating hormone releasing hormone (FSHRH) initially fractionated together. FSHRH obscured C-LHIH, and FSH assays guided fractionation. Factor C-LHIH and FSHRH were separated and purified by Sephadex and high pressure liquied chromatography. The resulting fractions of C-LHIH inhibited LH-release at 100-500 ng and did not inhibit thyrotropin releasing hormone-thyroid stimulating hormone response.

17] Methods for estimating the biologic activity of the luteinizing hormone- and follicle stimulating hormone-releasing hormone

Both in vitro and in vivo methods are used for estimating biologic activities of the substance, which probably is the physiological luteinizing hormone–releasing hormone (LH-RH), and follicle stimulating hormone-releasing hormone (FSH-RH), and its analogues. These methods involve the measurements of LH and FSH released from rat pituitaries into the incubation medium or into blood. These assays may be performed according to designs that permit statistical treatment of data and calculation of the relative potency, with 95% confidence limits of the material being tested with respect to the standard reference LH-RH/FSH-RH preparation. LH in incubation medium or blood is determined by a double antibody radioimmunoassay method for rat LH. FSH is determined either by the bioassay of Steelman and Pohley or a double antibody radioimmunoassay method for rat FSH.

Modification of in vitro neurotransmitter release from rat brain slices by hypophyseotropic factors

This chapter discusses the ultrashort feedback effects of releasing hormones. Previous experiments had indicated that the subcutaneous administration of crude hypothalamic extracts containing follicle-stimulating hormone–releasing hormone (FSH-RH) and devoided of any FSH and sex steroid contamination may bring about a significant reduction of FSH-RH stores in the hypothalamus of castrated, hypophysectomized rats. These experiments suggested the possibility that the brain might contain receptors sensitive to circulating levels of FSH-RH, and that FSH-RH might directly regulate its own production via an “ultrashort” feedback effect. Subcutaneous or intracarotid treatments with repeated doses of synthetic LH-RH are able to bring back to normal the elevated levels of hypothalamic LH-RH in castrated, hypophysectomized animals. The data support the view that releasing hormones have direct effects on the brain and speak in favor of the existence of “ultrashort” feedback mechanisms controlling gonadotropin secretion In addition, the chapter also provides information on the modification of in vitro neurotransmitter release from rat brain slices by hypophyseotropic factors.

Ultrashort feedback effects of releasing hormones

This chapter focuses on the ultrashort feedback effects of releasing hormones. Previous experiments had indicated that the subcutaneous administration of crude hypothalamic extracts containing follicle-stimulating hormone–releasing hormone (FSH-RH) and devoided of any FSH and sex steroid contamination may bring about a significant reduction of FSH-RH stores in the hypothalamus of castrated, hypophysectomized rats. These experiments suggested the possibility that the brain might contain receptors sensitive to circulating levels of FSH-RH, and that FSH-RH might directly regulate its own production via an “ultrashort” feedback effect. imilar experiments have now been repeated using synthetic LH-RH and its effects have been evaluated on hypothalamic LH-RH stores of castrated, hypophysectomized male rats. LH-RH contained in the hypothalamus has been evaluated injecting hypothalamic extracts into the carotid artery of castrated estrogen-pretreated female rats and measuring the rise of radioimmunoassayable LH in their serum.

Combined test for assessment of anterior pituitary function.

A combined test consisting of the simultaneous administration of insulin, thyrotrophin-releasing hormone (TRH), and luteinizing hormone and follicle stimulating hormone-releasing hormone (LH/FSH-RH) was performed in 24 people. Eleven of these also had the three individual tests performed separately, and the remaining 13 had a separate test of either LH/FSH-RH and TRH together or singly at a later date. In both normal people and patients, whether the tests were performed alone or in combination, no difference was found between the hormone responses (growth hormone, cortisol, LH, FSH, thyroid-stimulating hormone) seen to these stimuli.It is proposed that combined administration of insulin and the hypothalamic releasing hormones may be used as a single test for the assessment of anterior pituitary function. The test is convenient and time saving, and with care can be performed in outpatients.

Effect of synthetic luteinizing hormone- and follicle stimulating hormone-releasing hormone (LH-FSH-RH) on serum levels of LH, FSH, thyrotrophin (TSH) and growth hormone (HGH) in normal male subjects.

ABSTRACT Four normal male subjects received iv injections of synthetic luteinizing hormone- and follicle stimulating hormone-releasing hormone (LH/FSH-RH) in doses of 12.5, 25, 100, 200 and 400 μg, respectively. A dose of 12.5 μg of LH/FSH-RH caused a significant increase in serum FSH, and 25 μg significantly increased the serum LH. The peak responses occurred 15 to 30 min after the LH/FSH-RH injections in most of the experiments. The increase in the mean maximum serum LH and FSH levels was 2 to 4 fold. There was great variation in response between the subjects, but when tested repeatedly with the same dose of LH/FSH-RH a given individual responded in a consistent manner. The log dose-response curve between LH/FSH-RH and serum LH, and between LH/FSH-RH and serum FSH was approximately linear. A small but significant (P &lt; 0.05) rise in serum thyrotrophin (TSH) was found after LH/FSH-RH in doses ranging from 25 to 400 μg. There was no significant rise in serum growth hormone (HGH). On the basis of the present study a standard 100 μg iv LH/FSH-RH test is suggested.

Kinetics of release of luteinizing hormone (LH) and follicle stimulating hormone (FSH) by primary cultures of dispersed rat anterior pituitary cells. Chronic effect of synthetic LH and FSH releasing hormone

The kinetics of release of LH and FSH have been followed in primary cultures of dispersed rat anterior pituitary cells maintained up to two months, either in control media or in media containing 2ng/ml of LH-RH. In control cultures the LH and FSH contents in the media dropped during the first seven days, then decreased more slowly, and finally reached a low or undetectable level with some irregular variations. Starting on the 6th or 7 th day, the FSH/LH ratio increased and in some series FSH alone remained at a detectable level. The LH-RH induced an increase of both LH and FSH release. This increase appeared only after the first 5 days of culture. The stimulatory effect of LH release reached a maximum on day 11 to 13 and thereafter progressively decreased to the level of the control. The stimulatory effect of FSH release reached a maximum later than did that of LH, and generally remained significant for a longer time. The maximum of the FSH response was close or inferior to that of the LH response.

Serum LH levels in prepubertal female pigs chronically treated with synthetic luteinizing hormone-releasing hormone-follicle stimulating hormone-releasing hormone (LH-RH-FSH-RH).

A double—antibody radioimmunoassay utilizing a heterologous system specific for porcine luteinizing hormone (PLH) has been developed with rabbit antibovine LH serum as a first antibody. Porcine LH (LER-786-3) was used for iodination and as a reference standard. Reliable estimates of LH could be obtained in 200 pi of serum from immature pigs at any time. Porcine follicle-stimulating hormone (FSH), porcine thyroid- stimulating hormone, porcine adrenocorticotropic hormone or serum components per se did not affect measurements of LH. Ten prepubertal female pigs (mean wt 12.8 kg) were assigned randomly in equal numbers to a treated or control group. Treatment consisted of 16 im injections of 25 ng of pure synthetic LH and FSH releasing hormone (LH-RH/FSH-RH) in one ml of acidified saline or acidified saline only at 6–hr intervals over a period of 96 hr for treated and control animals respectively. Blood samples were collected via indwelling jugular catheters, at various times following each injection. Serum LH...

Release of LH and FSH after administration of synthetic LH-releasing hormone.

To study the effect of synthetic leutenizing hormone-releasing hormone (LH-RH) follicle stimulating hormone-releasing hormone (FSH-RH) on the release of LH and FSH in the human being, a decapeptide, synthesized by the solid phase method, was injected into normal volunteers 21-36 years old. There were 3 untreated men, 2 untreated women, 3 men pretreated with ethinyl estradiol and 3 women pretreated with an oral contraceptive (lyndiol). The synthetic hormone ((pyro)Glu-His-Trp-Ser-Tyr-Gly-Leu-Arg-Pro-Gly-NH2) caused an increase in serum LH values over the control (p less than .01) with no difference between men and women in the amount of LH released. FH was also significantly (p less than .01) increased but to lower levels than LH. Pretreatment with sex steroids led to a decrease in FSH values (p less than .10). Since the hormone is readily synthesized in large quantities, clinical studies are now possible.

Isolation of the Luteinizing Hormone and Follicle-stimulating Hormone-releasing Hormone from Porcine Hypothalami

Abstract A new procedure is described for the isolation on a preparative scale of a hypothalamic decapeptide which stimulates the release of both luteinizing hormone (LH) and follicle-stimulating hormone (FSH) from the pituitary. The isolation was achieved mainly by countercurrent distribution. The yield from 240,000 porcine hypothalami was 11.4 mg. Thin layer chromatography and electrophoresis showed the material to be homogeneous. The amino acid analyses showed the presence of 2 residues of glycine and 1 residue each of histidine, arginine, tryptophan, serine, glutamic acid, proline, leucine, and tyrosine. This decapeptide stimulates release of both LH and FSH in vivo as well as in vitro in doses smaller than 1 ng. It is thought to be the hypothalamic hormone which controls secretion of both LH and FSH from the pituitary gland.

Studies on the Properties of Hypothalamic Luteinizing Hormone-releasing Hormone

Abstract The effects of various chemical and enzymatic treatments on the biological activity of porcine luteinizing hormone-releasing hormone (LH-RH), which were performed before the elucidation of the structure of this hormone, are described. LH-RH activity was abolished by the following endopeptidases: chymotrypsin, subtilisin, papain, and thermolysin, but not by pepsin or trypsin. Exopeptidases did not affect LH-RH activity, but a purified preparation of pyrolidone carboxylpeptidase did. Treatment with various chemical reagents showed that tyrosine, histidine, tryptophan, and arginine in LH-RH are important for its biological activity. Nitrous acid and Edman degradation did not inactivate LH-RH. The results are in agreement with the determined structure of LH-RH. This hormone also showed a high follicle-stimulating hormone-releasing hormone activity. The inactivation of LH-RH was always accompanied by a loss of follicle-stimulating hormone-releasing hormone activity. These experiments also shed some light on the structure-activity relationship of this hormone.