OESTRADIOL STIMULATION OF PROLACTING RELEASE FROM CANINE PITUITARY IN CULTURE

1976 ◽  
Vol 82 (3) ◽  
pp. 706-709 ◽  
Author(s):  
Gwyneth E. Jones ◽  
A. R. Boyns
Keyword(s):  
Tissue Culture ◽  
Luteinizing Hormone ◽  
Prolactin Release ◽  
Luteinizing Hormone Releasing Hormone ◽  
Releasing Hormone ◽  
Thyrotrophic Hormone ◽  
Lh Rh ◽  
Stimulation Of

ABSTRACT Anterior canine pituitaries were maintained in tissue culture for 8 days, and the immunoreactive prolactin released, was measured by a heterologous radioimmunoassay for canine prolactin. Luteinizing hormone-releasing hormone (LH-RH) and thyrotrophic hormone-releasing hormone (TRH) did not affect prolactin release, while theophylline and oestradiol-17β stimulated the release of canine prolactin.

STIMULATION OF PROSTAGLANDIN ACCUMULATION IN THE RAT ANTERIOR PITUITARY GLAND BY LUTEINIZING HORMONE RELEASING HORMONE IN VITRO

1977 ◽  
Vol 75 (2) ◽  
pp. 277-283 ◽  
Author(s):  
N. BARDEN ◽  
A. BETTERIDGE
Keyword(s):  
Luteinizing Hormone ◽  
Cyclic Amp ◽  
Anterior Pituitary ◽  
Pituitary Cells ◽  
Luteinizing Hormone Releasing Hormone ◽  
Releasing Hormone ◽  
Lh Release ◽  
Lh Rh ◽  
Stimulation Of

The addition of luteinizing hormone releasing hormone (LH-RH) to cultures of monolayers of rat anterior pituitary cells was shown to increase both the concentrations of prostaglandins E1 and E2 (PGE) in the cells and the release of LH over similar ranges of concentrations of LH-RH (10−6 to 10−10 mol/l). The peak concentration of PGE was observed after 2·5 h. The stimulation of the level of PGE in the cells by LH-RH was completely inhibited by two inhibitors of prostaglandin synthetase, which only partially inhibited the stimulation of LH release. Therefore the increased concentration of PGE was not obligatory for the effect of LH-RH on LH release. It was also shown that monobutyryl cyclic AMP stimulated the intracellular concentration of PGE and it is suggested that the stimulation of PGE levels may be mediated by increased levels of cyclic AMP in the cells after the addition of LH-RH.

Effect of synthetic luteinizing hormone – releasing hormone (LH–RH) on ovarian development in Japanese medaka, Oryzias latipes

1977 ◽  
Vol 55 (1) ◽  
pp. 155-160 ◽  
Author(s):  
Kenneth Ka-Sing Chan
Keyword(s):  
Luteinizing Hormone ◽  
Ovarian Development ◽  
Gonadosomatic Index ◽  
Class Iii ◽  
Warm Temperature ◽  
Yolk Formation ◽  
Luteinizing Hormone Releasing Hormone ◽  
Releasing Hormone ◽  
Lh Rh ◽  
Stimulation Of

Regressed female medakas were injected with synthetic luteinizing hormone–releasing hormone (LH–RH) intraperitoneally twice a week for 6 weeks under warm temperature (23 ± 1 °C) and short photoperiod (8 h light: 16 h dark). A dose response was observed as shown by the gonadosomatic index and the percentage distribution of class III oocytes with yolk formation. Ovulation also occurred in fish injected with the highest dose. Pituitary cytology revealed stimulation of gonadotropic cells in the proximal pars distalis by synthetic LH–RH at doses of 100 and 1000 ng per gram body weight. Thus, synthetic LH–RH seems to be effective in inducing ovarian development in the medaka. In fish, the presence of a system similar to the mammalian LH–RH system seems likely.

LUTEINIZING HORMONE RESPONSIVENESS TO LUTEINIZING HORMONE RELEASING HORMONE IN THE ADULT GUINEA-PIG: DIRECT OVARIAN INVOLVEMENT

1978 ◽  
Vol 76 (1) ◽  
pp. 49-61 ◽  
Author(s):  
M. B. TER HAAR
Keyword(s):  
Luteinizing Hormone ◽  
Guinea Pig ◽  
Oestrous Cycle ◽  
Luteinizing Hormone Releasing Hormone ◽  
Releasing Hormone ◽  
Maximum Increment ◽  
Lh Rh ◽  
Dose Dependent ◽  
Ovarian Involvement ◽  
Stimulation Of

SUMMARY The effects of intravenous injection of synthetic luteinizing hormone releasing hormone (LH-RH) on the release of LH and FSH have been studied in the adult guinea-pig. In all the experiments the secretion of FSH was apparently unaffected by administration of LH-RH. The release of LH was log dose-dependent over the range 0·5–50 μg LH-RH. During the female cycle, the maximum increment in the concentration of LH after a single i.v. injection of 0·5 μg LH-RH decreased progressively from day 1 to day 13. Double or triple injections of 1 μg LH-RH at 1 h intervals produced no potentiation on day 3 but progressively greater LH responses occurred on days 7, 10 or 13 of the oestrous cycle. Ovariectomy immediately before the first injection of LH-RH on day 7 blocked the potentiated response to subsequent injections, whereas ovariectomy immediately before the second injection still permitted this potentiation. These results suggest that there is direct ovarian involvement in the potentiated response to LH-RH observed during the later part of the guinea-pig oestrous cycle. Infusion of LH-RH (1 μg over 200 min) produced a potentiated release of LH in female guinea-pigs on day 7 (but not on day 3) of the oestrous cycle after a delay of 1·5 h. It is proposed that there are two 'pools' of LH in the pituitary gland of the female guinea-pig and that the second pool is 'activated' consequent upon previous hypophysial stimulation of secretion from an ovary containing adequately developed follicles.

EFFECT OF GONADAL STEROIDS ON THE PITUITARY RESPONSIVENESS TO SYNTHETIC LUTEINIZING HORMONE RELEASING HORMONE IN THE MALE DOG

1974 ◽  
Vol 61 (1) ◽  
pp. 123-131 ◽  
Author(s):  
GWYNETH E. JONES ◽  
A. R. BOYNS
Keyword(s):  
Luteinizing Hormone ◽  
Gonadal Steroids ◽  
Luteinizing Hormone Releasing Hormone ◽  
Releasing Hormone ◽  
Intravenous Injections ◽  
Lh Rh ◽  
Lh Secretion ◽  
Stimulation Of

SUMMARY Intravenous injections of synthetic luteinizing hormone releasing hormone (LH-RH) stimulated LH secretion in male dogs. An i.m. injection of 0·025–2·5 mg oestradiol-17β given 2·5 h but not 24 h before administration of LH-RH blocked LH secretion. Diethylstilboestrol (2·5 mg) also blocked LH secretion but meso-dihydrodibutylstilboestrol (2·5 mg) was without effect. Testosterone (2·5 and 25 mg), dihydrotestosterone (2·5 mg), 5α-androstane-3α, 17β-diol (2·5 mg), 5α-androstane-3β, 17β-diol (2·5 mg), 5α-androstane-3α, 17α-diol (0·125 mg), 5α-androstane-3β, 17α-diol (0·125 mg) and progesterone (25 and 50 mg) did not prevent LH-RH stimulation of LH secretion.

Hypothalamic catecholaminergic effects on prolactin release in vitro

1978 ◽  
Vol 56 (2) ◽  
pp. 304-309 ◽  
Author(s):  
W. C. Friend ◽  
G. M. Brown ◽  
S. Kirpalani ◽  
D. Wilson
Keyword(s):  
Luteinizing Hormone ◽  
Thyrotropin Releasing Hormone ◽  
Prolactin Release ◽  
Luteinizing Hormone Releasing Hormone ◽  
Releasing Hormone ◽  
Release In Vitro ◽  
Lh Rh ◽  
Hypothalamic Mechanism

Hypothalamic catecholaminergic influences on prolactin release were investigated in vitro. Both dopamine and norepinephrine caused long lasting inhibition of prolactin release from either an isolated hemipituitary or a hemipituitary coincubated with a hypothalamus. Epinephrine also inhibited prolactin release. L-Dihydroxyphenylalanine (L-dopa) inhibited prolactin release from pituitaries in the presence of a hypothalamus but not in isolated pituitaries. DL-Threodihydroxyphenylserine (threodops), serotonin, 5-hydroxy-L-tryptophan (5-HTP), tyramine, octopamine, synephrine, thyrotropin-releasing hormone (TRH), luteinizing hormone releasing hormone (LH-RH), and somatostatin all failed to alter prolactin release. Results confirm that dopamine and norepinephrine directly inhibit prolactin release from pituitary and suggest that the hypothalamic mechanism inhibiting prolactin involves dopamine but not norepinephrine.

EFFECT OF CORTISOL OR ADRENOCORTICOTROPHIN ON RELEASE OF LUTEINIZING HORMONE INDUCED BY LUTEINIZING HORMONE RELEASING HORMONE IN THE DAIRY HEIFER

1982 ◽  
Vol 92 (1) ◽  
pp. 141-146 ◽  
Author(s):  
R. L. MATTERI ◽  
G. P. MOBERG
Keyword(s):  
Luteinizing Hormone ◽  
Luteinizing Hormone Releasing Hormone ◽  
Releasing Hormone ◽  
Dairy Heifers ◽  
Significant Difference ◽  
Significant Depression ◽  
Lh Rh ◽  
Lh Releasing Hormone ◽  
And Control ◽  
Slight Depression

During treatment with cortisol or ACTH, dairy heifers were given two doses of LH releasing hormone (LH-RH) spaced 1·5 h apart. Serum concentrations of cortisol and LH were monitored during each treatment. Treatment with both ACTH and cortisol raised plasma cortisol levels above the respective saline controls (P<0·001). Neither treatment affected basal LH concentrations. A slight depression in LH response was seen in the cortisol-treated animals after the first LH-RH injection, as shown by a statistically significant depression at three of the sample times. There was no significant difference between treated and control LH values after the second LH-RH administration. Treatment with ACTH resulted in significantly reduced LH values at all sample times after both injections of LH-RH.

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