Ovulation Induction and Antifertility Effects of an Lh-Rh Analogue (Ay-25,205) in Cyclic Rats

Banik, U. K.; Givner, Morris L.

doi:10.1530/jrf.0.0440087

Cited by 48 publications

(11 citation statements)

References 9 publications

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“…Thus, while LRF isolated from the hypothalamus possesses the ability to stimulate the secretion of both LH and FSH from the pituitary gland, chronic treatment with this peptide inhibits, to a great extent, many aspects of reproductive performance. Similar effects of LRF were confirmed with long acting, more GONADOCRININS 1207 potent agonistic analogs (super LRFs) (15)(16)(17)(18)(19).…”

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confidence: 61%

Gonadocrinins: Peptides in Ovarian Follicular Fluid Stimulating the Secretion of Pituitary Gonadotropins*

et al. 1981

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A newly discovered small peptide purified from rat follicular fluid stimulates the pituitary to release FSH and LH in vitro as well as in vivo. Dialysates of crude acid extracts of ovarian follicular tissue and fluid from rats pretreated with PMS gonadotropin stimulate the secretion of both LH and FSH, but not PRL, GH, or TSH, in a pituitary monolayer culture system. This stimulating factor, named gonadocrinin for operational facility, is smaller than 3500 daltons; its biological activity disappears after treatment with trypsin. Gonadocrinin is not recognized by two-antisera binding the decapeptide LRF even though D-Phe2,D-Trp6-LR, an LRF analog antagonist, competitively inhibits the activity of ovarian gonadocrinin. Cultured rat granulosa cells also secret substances with gonadocrinin activity in vitro, indicating that the granulosa cells probably are in vivo the source of gonadocrinin. A crude preparation of gonadocrinin given iv to rats on the second day of diestrus induced secretion of LH comparable to that produced by a 250-ng LRF injection. Gonadocrinin has chemical characteristics different from those of LRF. When purified gonadocrinin or LRF was applied to an identical isocratic high pressure liquid chromatography system, LRF was eluted at a position different from that of gonadocrinin, indicating that, chemically, gonadocrinin is not identical to the hypothalamic decapeptide, LRF.

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confidence: 61%

Gonadocrinins: Peptides in Ovarian Follicular Fluid Stimulating the Secretion of Pituitary Gonadotropins*

et al. 1981

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“…In rats both pre-and postcoital antifertility effects have been found (1,2), and these peptides also delay pubertal maturation (3) and inhibit FSH-induced ovarian weight gain (4). Similarly, in human subjects, GnRH analogs can inhibit ovulation (5) and exert a luteolytic action (6,7).…”

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confidence: 99%

Ovarian Gonadotropin-Releasing Hormone (GnRH) Receptors: Characterization, Distribution, and Induction by GnRH*

1981

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Gonadotropin-releasing hormone (GnRH) and its analogs have direct extrapituitary effects on the gonads to inhibit steroidogenesis. In the present study, the nondegradable GnRH analog [ 125 I]D-Ala a -des-Glyio-GnRH ethylamide is shown to specifically bind to ovarian, testicular, and adrenal membrane preparations. The ovarian GnRH receptor has a binding affinity similar to that of the anterior pituitary receptor and is specific for GnRH and GnRH analogs.The GnRH-binding capacity of whole ovarian membrane preparations is 150 fm/mg protein, 3-to 4-fold lower than that of anterior pituitary membranes. The number or affinity of receptors prepared from whole ovarian tissue is not influenced by the time of day, stage of the estrous cycle, or hypophysectomy. However, the GnRH receptor concentration is higher in follicular (371 ± 43 fmol/mg) than luteal (162 ± 25 fmol/mg) membranes from cycling rats.

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“…Such a mechanism offers an explanation for the early reports of delayed vaginal cornification and infertility in female rats treated with LHRH agonists (8,9,23). This is supported by the observations that treatment with LH and hCG can induce a loss of LH receptors in testis (13,14) and ovary (15,16) with a decreased response of ovarian adenylate cyclase to LH (15,16).…”

Section: Discussionmentioning

confidence: 76%

“…Such changes at the ovarian level are known to be accompanied by delayed mating and vaginal cornification (8,9). The interest of such studies is strengthened by the recent reports of a luteolytic effect of LHRH (10,11) as well as inhibition of ovulation by treatment with an LHRH agonist (12) in normal women.…”

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confidence: 99%

Inhibitory Effects of Long Term Treatment with a Luteinizing Hormone-Releasing Hormone Agonist on the Pituitary-Gonadal Axis in Male and Female Rats

et al. 1979

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Following previous observations of the potent antifertility effects of acute treatment with LHRH or its agonistic analogs in male and female rats, this study describes the effect of long term (up to 12 weeks) treatment with an LHRH agonist, [D-Ala6, des-Gly-NH210]LHRH ethylamide (LHRH-A), on testicular and ovarian gonadotropin receptor levels and function in the rat. Treatment of adult male rats with 100 ng LHRH-A every third day led to a progressive decrease of testis, seminal vesicle, and prostate weight up to 12 weeks of treatment, while the inhibitory effect (70%) on LH receptor levels was already maximal at 1 week. When adult female rats were injected daily with 5 microgram LHRH-A for 12 weeks, ovarian LH, FSH, and PRL receptor levels were reduced 50--90%, while plasma estradiol and progesterone levels were inhibited 60% (compared with diestrus day 1). The effect of chronic administration of a low dose (5 IU) of hCG in the male rat was transient. By contrast, no sign of resistance developed up to 12 weeks of treatment with the LHRH agonist in either male or female animals.

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Ovulation Induction and Antifertility Effects of an Lh-Rh Analogue (Ay-25,205) in Cyclic Rats

Cited by 48 publications

References 9 publications

Gonadocrinins: Peptides in Ovarian Follicular Fluid Stimulating the Secretion of Pituitary Gonadotropins*

Gonadocrinins: Peptides in Ovarian Follicular Fluid Stimulating the Secretion of Pituitary Gonadotropins*

Ovarian Gonadotropin-Releasing Hormone (GnRH) Receptors: Characterization, Distribution, and Induction by GnRH*

Inhibitory Effects of Long Term Treatment with a Luteinizing Hormone-Releasing Hormone Agonist on the Pituitary-Gonadal Axis in Male and Female Rats

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