APPLICATION OF AN IN-VITRO PERIFUSION TECHNIQUE TO STUDIES OF LUTEINIZING HORMONE RELEASE BY RAT ANTERIOR HEMI-PITUITARIES: SELF-POTENTIATION BY LUTEINIZING HORMONE RELEASING HORMONE

1976 ◽  
Vol 68 (2) ◽  
pp. 197-207 ◽  
Author(s):  
J. A. EDWARDSON ◽  
D. GILBERT
Keyword(s):  
Luteinizing Hormone ◽  
Priming Effect ◽  
Hormone Release ◽  
Physiological Control ◽  
Luteinizing Hormone Releasing Hormone ◽  
Releasing Hormone ◽  
Hypothalamic Extract ◽  
Lh Rh ◽  
Lh Secretion

SUMMARY A technique is described for the continuous perifusion of rat adenohypophyses. Exposure of the perifused glands to repeated equal 5 min stimuli with hypothalamic extract resulted in a series of equal peaks of corticotrophin secretion, the response was proportional to log dose over the range 0·25–2·0 rat hypothalamic equivalents/ml. Repeated equal stimuli with hypothalamic extract, or with luteinizing hormone releasing hormone (LH-RH) at concentrations of 2 or 10 ng/ml, resulted in a progressively increasing series of peaks of LH secretion, i.e. a self-potentiating or priming effect. The effect took between 30 min and 1 h to develop. A delayed increase in the responsiveness of the glands was also seen with continuous incubation of anterior pituitaries with LH-RH. The relevance of these observations to the physiological control of LH secretion is discussed.

INHIBITION BY MELATONIN OF THE PITUITARY RESPONSE TO LUTEINIZING HORMONE RELEASING HORMONE IN VIVO

1978 ◽  
Vol 76 (3) ◽  
pp. 487-491 ◽  
Author(s):  
K. YAMASHITA ◽  
M. MIENO ◽  
T. SHIMIZU ◽  
ER. YAMASHITA
Keyword(s):  
Luteinizing Hormone ◽  
Carotid Artery ◽  
Anterior Pituitary ◽  
Chorionic Gonadotrophin ◽  
Human Chorionic Gonadotrophin ◽  
Luteinizing Hormone Releasing Hormone ◽  
Releasing Hormone ◽  
Lh Rh ◽  
Lh Secretion

The rate of secretion of 17-oxosteroids by the testes of anaesthetized dogs in vivo was used as an index of LH secretion. Intracarotid injection of luteinizing hormone releasing hormone (LH-RH, 1, 5 or 10 μg/kg body wt) resulted in an increase in the testicular 17-oxosteroid secretion which was roughly proportional to the dose administered and which reached a maximum 60 min after the injection. Testicular output of 17-oxosteroids was unaffected by administration of melatonin (10 or 100 μg/kg body wt) into the carotid artery. When LH-RH (5 μg/kg) was injected into the carotid artery 3 h after intracarotid injection of melatonin (10 or 100 μg/kg), the testicular response to LH-RH was considerably diminished. Pretreatment with melatonin (100 μg/kg) did not alter the testicular response to human chorionic gonadotrophin (20 i.u./kg body wt) given i.v. It is concluded that melatonin may act directly on the anterior pituitary gland in dogs to inhibit the LH-RH-induced release of LH.

Antagonistic activity of analogs of luteinizing hormone-releasing hormone (LH-RH) in vitro

1976 ◽  
Vol 5 (3-4) ◽  
pp. 201-208 ◽  
Author(s):  
D.H. Coy ◽  
F. Labrie ◽  
M. Savary ◽  
E.J. Coy ◽  
A.V. Schally
Keyword(s):  
Luteinizing Hormone ◽  
Antagonistic Activity ◽  
Luteinizing Hormone Releasing Hormone ◽  
Releasing Hormone ◽  
Lh Rh

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.

scholarly journals Role of nitric oxide in the control of luteinizing hormone-releasing hormone release in vivo and in vitro.

1993 ◽  
Vol 90 (21) ◽  
pp. 10130-10134 ◽  
Author(s):  
V. Rettori ◽  
N. Belova ◽  
W. L. Dees ◽  
C. L. Nyberg ◽  
M. Gimeno ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Luteinizing Hormone ◽  
Hormone Release ◽  
Luteinizing Hormone Releasing Hormone ◽  
Releasing Hormone

EFFECTS OF LUTEINIZING HORMONE RELEASING HORMONE ON PLASMA FOLLICLE-STIMULATING HORMONE AND LUTEINIZING HORMONE LEVELS IN THE FERRET

1977 ◽  
Vol 73 (1) ◽  
pp. 37-52 ◽  
Author(s):  
B. T. DONOVAN ◽  
M. B. TER HAAR
Keyword(s):  
Luteinizing Hormone ◽  
Intravenous Injection ◽  
Follicle Stimulating Hormone ◽  
Luteinizing Hormone Releasing Hormone ◽  
Releasing Hormone ◽  
Hormone Levels ◽  
Oestradiol Treatment ◽  
Gonadotrophin Secretion ◽  
Lh Rh ◽  
Lh Secretion

SUMMARY Heterologous radioimmunoassays for FSH and LH were employed to examine the effect of synthetic LH-RH upon gonadotrophin secretion in the ferret. Intravenous injection of 4 μg LH-RH induced a surge of FSH and of LH secretion in male and in female animals. In intact and in castrated males, the rise of LH was much more marked than that of FSH. The gonadotrophin response to LH-RH was greater in anoestrous than in oestrous females; FSH secretion was not enhanced during oestrus. Ovariectomized females behaved as anoestrous females with respect to LH secretion, while FSH secretion remained unchanged. Treatment of ovariectomized females with progesterone did not alter the pattern of response to LH-RH, but oestradiol treatment depressed the reaction to match that seen in oestrous females. Repetitive injections of LH-RH induced repetitive surges of FSH and LH in anoestrous females, but only of LH during oestrus: slow i.v. infusion of LH-RH induced a sustained elevation of plasma LH levels both in oestrous and in anoestrous females; again FSH levels rose only in anoestrous females. Injection of synthetic TRH did not alter gonadotrophin secretion in corresponding groups of male or female ferrets.

Comparison of pharmacological effect of adiphenine and physiological stimulation by luteinizing hormone releasing hormone on luteinizing hormone release by rat anterior pituitaries in vitro

1979 ◽  
Vol 57 (12) ◽  
pp. 1388-1392 ◽  
Author(s):  
M. Fevre ◽  
D. Jordan ◽  
J. Tourniaire ◽  
R. Mornex
Keyword(s):  
Luteinizing Hormone ◽  
Dependent Manner ◽  
Similar Time ◽  
Luteinizing Hormone Releasing Hormone ◽  
Releasing Hormone ◽  
Calcium Dependent ◽  
Lh Release ◽  
Time Courses ◽  
Lh Rh

The mechanism of action of adiphenine on in vitro rat anterior pituitary LH release was studied and compared with that of the physiological stimulator luteinizing hormone releasing hormone (LH-RH) on LH release. The comparative study showed that adiphenine and LH-RH were able to increase medium LH concentration in a dose-dependent manner and had similar time courses of action between 1 and 4 h incubation. However, there were several main differences between the effects of adiphenine and LH-RH. The adiphenine action was not calcium dependent, was inhibited in a high K+ medium concentration, and was substituted after energy depression. It is concluded that adiphenine probably acts near the ultimate steps of the LH release pathway and could be a useful pharmacological tool for studying the mechanism of LH release.

Sign in / Sign up

Export Citation Format

Share Document