Structure-Activity Relationships in the Lh-Rh Molecule

Sandow, J.; König, Wolfgang; Geiger, R.; Uhmann, Rainer; Rechenberg, W. von

doi:10.1016/b978-0-408-70924-8.50010-4

Cited by 14 publications

(9 citation statements)

References 58 publications

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“…Under these conditions. LHRH receptors may be desensi tized as observed following treatment with high amounts of exogenous neuropeptide [18]. The effects of desensitiza tion would decrease after the tissue had been cultured for some time.…”

Section: Discussionmentioning

confidence: 99%

Kinetic Characteristics of LH and FSH Responses to LHRH in Incubated Pituitaries from Ovariectomized or Ovariectomized, Estrogen-Implanted Rats

Kordon¹,

Patton²,

Rotsztejn³

et al. 1980

Neuroendocrinology

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Incubated pituitary halves from ovariectomized, estrogen-implanted female rats were shown to be much more sensitive to LHRH than pituitaries from castrated, nontreated animals. LHRH in a concentration of 1,885 pg/ml increased the release of LH and FSH from 7.3 ± 0.9 and 0.91 ± 0.13 ng/h/hemipituitary respectively to 21.4 ± 1.9 and 1.97 ± 0.18 ng/h in animals implanted with the steroid. In contrast, 5,000 pg/ml of LHRH increased LH secretion from 3.4 ± 0.3 to 8.4 ± 0.4 ng/h in ovariectomized, nontreated animals. In pituitaries from both steroid and nontreated animals a highly significant dose response for LH and FSH secretion to the actual concentration of LHRH measured in each incubation tube by radioimmunoassay was observed. When expressed as percent of the corresponding control release, maximal stimulation of LH and FSH was comparable. Pituitaries from implanted animals provided a very sensitive bioassay for LHRH, in which amounts of the peptide lower than 100 pg/ml were detected. The apparent responsiveness to LHRH of pituitaries from estradiol-treated rats was found to be over 20 times greater than that of pituitaries from nontreated castrates.

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Section: Discussionmentioning

confidence: 99%

Kinetic Characteristics of LH and FSH Responses to LHRH in Incubated Pituitaries from Ovariectomized or Ovariectomized, Estrogen-Implanted Rats

Kordon¹,

Patton²,

Rotsztejn³

et al. 1980

Neuroendocrinology

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“…2, FSH substantially increases progesterone production by cultured granulosa cells. Concomitant treatment with increasing concentrations of GnRH causes a dose-dependent inhibition of the FSH stimulation of progesterone production with an ED 5 FSH also stimulates estrogen production (148, 149) as well as LH and PRL receptor formation by these cultured granulosa cells (156,157). Concomitant treatment with GnRH or its agonists inhibits FSH stimulation of estrogen production as well as LH and PRL receptor formation, whereas the inhibitory effect of GnRH is blocked by the GnRH antagonist (152,(158)(159)(160).…”

Section: Granulosa Cellsmentioning

confidence: 98%

“…After the subsequent purification and sequencing of gonadotropin-releasing hormone (GnRH) (2,3) and the synthesis of potent GnRH agonists and antagonists (4,5), many laboratories have investigated the effects of these peptides on various reproductive functions. In both males and females, administration of GnRH or its potent agonists results in sustained increases in serum gonadotropins.…”

Section: Introductionmentioning

confidence: 99%

Extrapituitary Actions of Gonadotropin-Releasing Hormone*

1981

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“…At low concentrations of immunoreactive buserelin, only inactive metabolites are excreted in the urine. It is well established that only intact buserelin has biological activity (Sandow et al 1978). …”

Section: Discussionmentioning

confidence: 98%

LRH agonist buserelin as a post-partum contraceptive: lack of biological activity of buserelin in breast milk

Dewart

McNeilly

Smith

et al. 1987

Acta Endocrinologica

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To evaluate the possibility of using the LRH agonist buserelin as a contraceptive for lactating women we have investigated the passage of buserelin into breast milk and explored possible biological activity in the infant. Eleven mothers received 600 \ g=m\ gbuserelin by nasal spray. Buserelin was measured by radioimmunoassay in the breast milk of these mothers, and values ranged from undetectable levels (less than 15 pg/ml) to 8800 pg/ml. The maximum amount of buserelin that an infant could ingest during an average feed would be 1\p=n-\2\g=m\g.In adult men ingestion of 600 \ g=m\ g buserelin dissolved in cows milk was without biological effect upon both serum and urinary levels of luteinizing hormone. There was no change in the levels of LH found in the urine of infants fed by women who had received 600 \g=m\g buserelin by nasal spray. We conclude that the small amount of buserelin passing into the breast milk of these volunteers was without biological activity when ingested by the infant.The choice of contraceptive methods presently available to lactating mothers is limited. There is a need for a reliable, acceptable and easily admini¬ stered method of contraception which does not interfere with lactation and is non-steroidal. To this end we are currently evaluating the effective¬ ness of luteinizing hormone releasing hormone agonist (LRH agonist), buserelin, as a contracep¬ tive for lactating women. This report outlines the investigations that have been carried out prior to regular administration of buserelin to breast feeding mothers.Breast feeding is nutritionaly good for the infant (Buchanan 1975). The contraceptive effects of breast feeding have been investigated (Howie & McNeilly 1982;Short 1984), and it has been shown that while full breast feeding is asso¬ ciated with the suppression of ovarian activity in women post-partum when supplementary feeds are given (Howie et al. 1981) or when suckling activity declines to less than 50 min/day nursing (McNeilly et al. 1983), follicular development and ovulation resume. Steroidal forms of contracep¬ tion are the most practical method currently avail¬ able but are not ideal. Combined oral contracep¬ tives may have an adverse effect upon breast milk production (Koetswang 1982). The progestogen only pill is commonly prescribed to lactating women in developed countries, but troublesome side effects include irregular vaginal bleeding, nausea, vomiting and headache.Numerous studies have demonstrated that daily adinistration of LRH agonist to women with nor¬ mal menstrual cycles is a reliable and reversible method of suppressing ovulation (e.g. Bergquist et al. 1979; Schmidt-Gollwitzer et al. 1981). Our hypothesis is that buserelin administered to breast feeding women will reliably suppress ovulation

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Structure-Activity Relationships in the Lh-Rh Molecule

Cited by 14 publications

References 58 publications

Kinetic Characteristics of LH and FSH Responses to LHRH in Incubated Pituitaries from Ovariectomized or Ovariectomized, Estrogen-Implanted Rats

Kinetic Characteristics of LH and FSH Responses to LHRH in Incubated Pituitaries from Ovariectomized or Ovariectomized, Estrogen-Implanted Rats

Extrapituitary Actions of Gonadotropin-Releasing Hormone*

LRH agonist buserelin as a post-partum contraceptive: lack of biological activity of buserelin in breast milk

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