SUPPRESSION OF LUTEINIZING HORMONE RELEASE BY 5α-ANDROSTANE-3α,17β-DIOL AND ITS 3β EPIMER IN IMMATURE OVARIECTOMIZED RATS

1976 ◽  
Vol 70 (1) ◽  
pp. 25-30 ◽  
Author(s):  
B. ECKSTEIN ◽  
S. YEHUD ◽  
J. SHANI ◽  
G. GOLDHABER
Keyword(s):  
Body Weight ◽  
Luteinizing Hormone ◽  
Ovariectomized Rats ◽  
Hormone Release ◽  
Vaginal Opening ◽  
Luteinizing Hormone Release ◽  
Immature Rats ◽  
Oestradiol Benzoate ◽  
Lh Release

SUMMARY The effect of 5α-androstane-3α,17β-diol, its 3β epimer and oestradiol benzoate on suppression of LH release after ovariectomy was studied in immature rats. At doses of 50 and 100 μg/100 g body weight/day the 3α compound suppressed LH release after ovariectomy to the same extent as 0·1 μg oestradiol benzoate/100 g/day. 3α-Androstanediol at a dose of 25 μg/100 g/day suppressed LH release only up to day 45 of life, while the same dose of the 3β epimer had no effect on LH suppression. The effect of 3β-androstanediol on inducing precocious vaginal opening was found to be mediated by the ovaries, since it was eliminated by ovariectomy. These results confirm our previous findings on the participation of androstanediol in the normal regulation of LH and in the mechanism of onset of puberty in the rat.

The Role of Neural Inputs from the Posterior Arcuate Nucleus in Pulsatile Luteinizing Hormone Release in Ovariectomized Rats.

2010 ◽  
Vol 83 (Suppl_1) ◽  
pp. 575-575
Author(s):  
Yoshihisa Uenoyama ◽  
Saya Watanabe ◽  
Kinuyo Iwata ◽  
Satoshi Ohkura ◽  
Kei-ichiro Maeda ◽  
...  
Keyword(s):  
Luteinizing Hormone ◽  
Arcuate Nucleus ◽  
Ovariectomized Rats ◽  
Hormone Release ◽  
Luteinizing Hormone Release

Role of α-Adrenergic Mechanism in Regulating Tonic Luteinizing Hormone Release in Conscious Ovariectomized Rats*

Endocrinology ◽  
1981 ◽  
Vol 108 (4) ◽  
pp. 1272-1275 ◽  
Author(s):  
F. KINOSHITA ◽  
Y. NAKAI ◽  
H. KATAKAMI ◽  
Y. KATO ◽  
H. IMURA
Keyword(s):  
Luteinizing Hormone ◽  
Ovariectomized Rats ◽  
Hormone Release ◽  
Luteinizing Hormone Release ◽  
Adrenergic Mechanism

EFFECTS OF AN ANTI-OESTROGEN, TAMOXIFEN (ICI 46,474), ON LUTEINIZING HORMONE RELEASE AND OVULATION IN THE HEN

1981 ◽  
Vol 88 (2) ◽  
pp. 309-316 ◽  
Author(s):  
SUSAN C. WILSON ◽  
F. J. CUNNINGHAM
Keyword(s):  
Luteinizing Hormone ◽  
Pituitary Gland ◽  
Intramuscular Injection ◽  
Hormone Release ◽  
Luteinizing Hormone Release ◽  
Facilitative Role ◽  
Lh Release ◽  
Lh Rh ◽  
Lh Releasing Hormone

The role of oestradiol in the regulation of LH release in the hen was studied by use of the anti-oestrogen, tamoxifen (ICI 46,474). Intramuscular injection of laying hens with 2 or 4 mg tamoxifen on 2 successive days delayed or prevented the occurrence of the preovulatory release of LH and ovulation expected on day 3. Ovulation could be restored by i.v. injection of 20 pg LH releasing hormone (LH-RH). Tamoxifen at a dose of 1 mg affected neither the timing of the preovulatory release of LH nor ovulation. Treatment with 2 or 4 mg tamoxifen on 2 successive days reduced the effectiveness of an i.m. injection of progesterone to stimulate a release of LH. Injection of 1, 2 or 4 mg tamoxifen on 2 successive days significantly raised basal levels of LH in the blood at 24 h after the last injection. This was associated with an increase in the capacity of the pituitary gland to respond to an injection of synthetic LH-RH by a release of LH. These studies suggest that oestradiol has at least two roles in the regulation of LH release in the hen. First, it maintains a low basal level of LH in the blood by reducing the responsiveness of the pituitary gland to LH-RH. Secondly, oestradiol has a facilitative role in the mechanism by which progesterone stimulates the preovulatory release of LH.

Sign in / Sign up

Export Citation Format

Share Document