Steroid Priming of the Luteinizing Hormone Response to Luteinizing Hormone Releasing Hormone

Beck, Lyle V.; Bay, María Luisa; Smith, Akimi; King, Dixie; Long, R. J.

doi:10.1677/joe.0.0770293

Cited by 11 publications

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“…In the hypothalamus, suckling increases the threshold of sensitivity to the negative retro-action of oestradiol on the tonic center (Acosta et al, 1983). Suckling inhibits oestrogen synthesis by the follicular cells (Bellin et a/., 1984) for a few days but not for three weeks after calving (Walters et al, 1982a (Zolman et al, 1974 ;Yen et al, 1974 ;Kesler et al, 1977 ;Beck et al, 1978 ;Hsueh et al, 1979 ;Zaied et al, 1980 ;Kesner et al, 1981 ;Azzazi et al, 1983 ;Peters, 1984).…”

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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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confidence: 99%

Endocrine regulation of postpartum ovarian activity in cattle : a review

Hanzen

1986

Reprod. Nutr. Dévelop.

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“…Additionally, a much smaller priming dose of LHRH was utilized. The precise response of the anterior pituitary to a single injection of L.HRH in the castrated male rat is a complex function of the amount of androgen present and the dose of LHRH administered [2,13,20,[22][23][24][25]. Such may also be the case for the self-priming ef fect.…”

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Androgenic and Estrogenic Control of the Self-Priming Effect of LHRH in the Castrated Male Rat

Nazian¹

1986

Neuroendocrinology

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Intact pubertal or young adult male rats release more luteinizing hormone in response to luteinizing hormone releasing hormone (LHRH) if pretreated with LHRH than if pretreated with saline. Castrated male rats do not show this self-priming effect of LHRH. In an attempt to determine the testicular factor responsible for the maintenance of the self-priming effect, pubertal male rats were castrated and implanted subcutaneously with various sizes of testosterone-filled Silastic capsules. Control rats were castrated or sham-operated and implanted with empty capsules. Rats were examined for a self-priming effect 4 days later. All sizes of testosterone capsules used maintained the self-priming effect. Three additional experiments were performed to determine the ability of dihydrotestosterone, estradiol and androstenedione to maintain a self-priming effect. The following groups were included in each experiment: castrated plus empty capsule, castrated plus testosterone-filled capsule, castrated plus one of two sizes of capsule filled with the steroid of interest, and sham-operated plus empty capsule. Dihydrotestosterone and estradiol, but not androstenedione were capable of maintaining a self-priming effect. Since it is generally considered that dihydrotestosterone cannot be aromatized to estrogen, this action of estradiol and dihydrotestosterone is probably accomplished by different mechanisms.

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