Antifertility effects of GnRH

Fraser, Hamish M.

doi:10.1530/jrf.0.0640503

Cited by 30 publications

(10 citation statements)

References 38 publications

(40 reference statements)

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“…However, we cannot rule out an ovarian local effect of this hormone on the synthesis of progesterone (Mc Natty et al, 1976, 1977 and on follicular development (Tsai-Morris et a/., 1983). The prolactin follicular concentration and the number of LH receptors are in fact significantly higher in weaned cows than in suckled cows (Walters et al, 1982a (Channing, 1978 ;Fraser, 1982 ;Sharpe, 1982) cannot play a determining part in the LH release mechanism after calving.…”

Section: Progesteronementioning

confidence: 93%

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Endocrine regulation of postpartum ovarian activity in cattle : a review

Hanzen

1986

Reprod. Nutr. Dévelop.

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Summary. The Clinically, the postpartum period is characterized by a period of behavioural anoestrus, the duration of which differs in different breeds.If the detection of oestrus is optimal, anoestrus lasts for 20 to 70 days in dairy cows Callahan et al., 1971 ;Schams et al., 1978 ;Pirchner et al., 1983 ;Richardson et al., 1983 ;Etherington et al., 1984). This period is highly variable in suckled cows and lasts from 30 to 110 days (Wiltbank and Cook 1958 ;Oxenreider 1968 ;Graves et al., 1968 ;Casida et al., 1968 ; Nancarrow et al., 1977 ;Holness et al., 1978 ;Wettemann et a/., 1978 ;Short et al., 1979 ;Dunn and Kaltenbach, 1980 ;Kesler et al., 1980 ;Randel, 1981 ;Montgomery, 1982 ;Peters and Riley, 1982 . Jainudeen et al., 1982Bastidas et al., 1984 ;King and Mc Leod, 1983Leod, /1984Hansen and Hauser, 1984 ;Montgomery et al., 1985).Assay of progesterone in plasma or milk has shown that 88 % of animals of dairy breeds have an luteal activity present by 35 days after calving (Ball and Lamming, 1983) and 95 % within 50 days (Bulman and Lamming, 1978). According to different authors, the first rise of progesterone appears between 16 and 69 days after calving in dairy cows (Webb et al., 1977(Webb et al., , 1980Pirchner et al., 1983) and between 56 and 96 days in suckled cows (Fonseca et al., 1980 ;Peters and Riley 1982 ; Jainudeen et al., 1982 Jainudeen et al., /1983Montgomery et al., 1985).It is possible to detect ovarian follicles by rectal palpation in both milked and suckled cow from the second week after calving (Saiduddin et al., 1968 ;Callahan et al., 1971 ;Kesler et al., 1979 ;Webb et al., 1980 ;Kesler et al., 1980 ;Stevenson et al., 1983 (Wiltbank et al., 1962(Wiltbank et al., , 1964Dunn et al., 1969 ; Lammond, 1970 ;Corah et al., 1975 ;Whitman et a/., 1975 ;Duffour, 1975 ;Holness et al., 1978 ;Carstairs et al., 1980 ;Dunn and Kaltenbach, 1980 ; Gauthier and Thimonnier, 1982 ;Peters and Riley, 1982 ; Mc Leod, 1983/1984 ;Rutter and Randel, 1984). Some authors have found that overfeeding improves ovarian (Wiltbank et al., 1962(Wiltbank et al., , 1964Hansen et al., 1982) or pituitary (Beal et al., 1978 ;Jordan and Swanson, 1979 ;Lishman et al., 1979 ;Moss et al., 1982) function. Others have found no relation between feeding and the ovarian (Lishman et al., 1979 ;Carstairs et al., 1980) or pituitary (Hill et a/., 1970 ;Dunn et al., 1974 ;Spitzer et al., 1978 ;Haresign, 1981 ;Rutter and Randel, 1984) activity.Little is known about the mechanism under which diet exerts its effect. It is conceivable that feeding influences the ovarian response to gonadotropins (Gombe and Hansel, 1973). There was a positive correlation between the degree of fatness of an animal and the plasma concentration of 17 !3-oestradiol, 7 weeks after calving (Lishman et al., 1979).Feeding affects the release of luteinizing hormone (LHI and subsequent luteal function Spitzer et al., 1975 ;Apgar et al., 1975 ;Beal et al., 1978). It has been observed that the release of LH induced by gonadotropin releasing hormone (GnRH) injection was grea...

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Section: Progesteronementioning

confidence: 93%

“…Experiments carried out with ovariectomized animals confirm that the ovary and its steroidal or peptide factors (Channing, 1978 ;Fraser, 1982 ;Sharpe, 1982) cannot play a determining part in the LH release mechanism after calving.…”

Section: Other Hormonal Factorsmentioning

confidence: 98%

Endocrine regulation of postpartum ovarian activity in cattle : a review

Hanzen

1986

Reprod. Nutr. Dévelop.

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“…Studies in rats (10)(11)(12)(13)(14)(15) demonstrated inhibition of testosterone secretion, reduction of testicular LH receptors, and prostate regression with chronic administration of this compound. This ability to induce "reproductive atrophy" pharmacologically with this agent has suggested its potential usefulness in androgen-dependent neoplasia.…”

Section: Introductionmentioning

confidence: 99%

Effect of very high dose D-leucine6-gonadotropin-releasing hormone proethylamide on the hypothalamic-pituitary testicular axis in patients with prostatic cancer.

Warner¹,

Worgul²,

Drago³

et al. 1983

J. Clin. Invest.

100

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A B S T R A C T Potent synthetic analogs of gonadotropin-releasing hormone produce parodoxical antireproductive effects when administered chronically. These compounds are minimally toxic and may exhibit no plateau of the dose-response curve even at very high doses. These considerations served as the basis for our systematic evaluation of [D-leucine6-desarginine-glycine-NH210]gonadotropin-releasing hormone (GnRH-A) proethylamide in the very high dose range (i.e., 10-fold larger amounts than previously used). In rats given the analog for 12

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“…Induced moulting results in a profound decrease in the body weight of the birds (Smith et al, 1957;Brake and Thaxton, 1979;Baker et al, 1983;Karunajeewa et al, 1989) and causes a decrease in the secretion of luteinising hormone (LH) from the pituitary gland (Tanabe et al, 1981;1982;Etches et al, 1984) and progesterone (Tanabe et al, 1981;1982;Johnson and van Tienhoven, 1981;Gildersleeve et al,1982;Etches et al, 1984;Dickerman and Bahr, 1989) from the ovary. There is also a reduction in the sensitivity of the pituitary gonadotrophs to gonadotrophin releasing hormone (GnRH: Tanabe et al, 1982) and a reduced response of the ovary to LH induced progesterone production in birds that are fasted (Verheyen et al, 1987).…”

Section: Introductionmentioning

confidence: 99%

“…In a wide range of mammalian species it has generally been found that the prolonged continuous treatment with GnRH or an agonist of GnRH will inhibit reproductive function (rat: Labrie et al, 1978;hamster: Sandow and Hahn, 1978;dog: Sandow et al, 1980;ram: Lincoln et al, 1986;rhesus monkey: Sundaram et al, 1982;baboon;Vickery and McRae, 1980;man: Linde et al, 1981). Continuous exposure to GnRH eventually leads to desensitisation of the pituitary to GnRH with a consequent loss of ovarian cyclicity in the female (Fraser, 1982) and involution of the testes in the male (Labrie et al, 1980). In hens it was found in one study that daily injection of the mammalian GnRH agonist buserelin, at doses that caused complete loss of fertility in female rats, did not affect egg production (Sterling and Sharp, 1984) Downloaded by [McGill University Library] at 02:30 08 February 2015 whereas in another study repeated injections into incubating hens, at more frequent intervals, resulted in loss of pituitary gland responsiveness and LH concentrations were not maintained (Sharp et al, 1986).…”

Section: Introductionmentioning

confidence: 99%

Short‐term reduction in egg production in laying hens treated with an agonist of GnRH

Tilbrook

Johnson

Eason

et al. 1992

British Poultry Science

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1. In two experiments laying hens were treated with an agonist of gonadotrophin releasing hormone (GnRH) to induce a reduction in the secretion of luteinising hormone (LH) and a pause in egg production. 2. In experiment 1, 70-week-old laying hens were either given daily subcutaneous injections of saline for 7 d, offered whole oats for 7 d (nutrient restriction), given daily injections of the GnRH agonist [D-Trp6-Pro9 N-ethyl amide]GnRH for 7 d at 50 micrograms/kg or 100 micrograms/kg or administered 4 biocompatible implants each containing 120 micrograms of the GnRH agonist. 3. Weekly egg production was monitored for 7 weeks and blood samples were taken at weekly intervals and assayed for plasma LH and oestradiol. Egg production was reduced in the birds treated with the agonist (28 to 46% reduction) but not to the same extent as in the birds offered whole oats (92.3% reduction). 4. The treatments also reduced plasma LH and oestradiol in treated hens but again to a greater extent in the birds offered whole oats than the birds treated with the agonist. Egg production and plasma LH and oestradiol increased following the termination of the treatments. 5. The birds fed whole oats suffered a reduction in weight of 16.7% over the treatment period whereas there were increases in the weights of the birds treated with saline, 50 micrograms of GnRH agonist and the implants of GnRH agonist, but no change in birds treated with 100 micrograms of GnRH agonist. 6. The birds fed oats lost feathers over the treatment period but the birds in the other treatment groups suffered no loss. 7. In experiment 2 laying hens were either injected daily with saline or 200 micrograms GnRH agonist and weekly egg production and plasma LH and oestradiol were measured. As egg production was reduced by almost 60% in the birds treated with the agonist but did not completely cease. Reductions in plasma LH and oestradiol were also observed. All variables increased to pretreatment levels once treatment ceased. 8. These data confirm the effects of severely depriving hens of nutrients on egg production and the secretion of LH and oestradiol.(ABSTRACT TRUNCATED AT 400 WORDS)

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Antifertility effects of GnRH

Cited by 30 publications

References 38 publications

Endocrine regulation of postpartum ovarian activity in cattle : a review

Endocrine regulation of postpartum ovarian activity in cattle : a review

Effect of very high dose D-leucine6-gonadotropin-releasing hormone proethylamide on the hypothalamic-pituitary testicular axis in patients with prostatic cancer.

Short‐term reduction in egg production in laying hens treated with an agonist of GnRH

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