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.

THE EFFECT OF LUTEINIZING HORMONE-RELEASING HORMONE AND STEROIDS ON THE RELEASE OF LH AND FSH FROM INCUBATED TURKEY PITUITARY CELLS

1977 ◽  
Vol 85 (4) ◽  
pp. 713-717 ◽  
Author(s):  
Patricia M. M. Godden ◽  
M. R. Luck ◽  
C. G. Scanes
Keyword(s):  
Luteinizing Hormone ◽  
Follicle Stimulating Hormone ◽  
Steroid Treatment ◽  
Cell Suspensions ◽  
Pituitary Cell ◽  
Pituitary Cells ◽  
Luteinizing Hormone Releasing Hormone ◽  
Releasing Hormone ◽  
Lh Rh ◽  
Lh Secretion

ABSTRACT The secretion of immunoreactive luteinizing hormone (IR-LH) and follicle stimulating hormone (IR-FSH) by turkey pituitary cell suspensions has been investigated. No significant effects of synthetic ovine luteinizing hormone-releasing hormone (LH-RH) on gonadotrophin release were found with cells from 17 to 19 week old birds, though IR-LH secretion was elevated with tissue from young (13 weeks) birds. Although IR-FSH secretion was increased in the presence of progesterone alone, effects of oestradiol and testosterone on IR-FSH release and of oestradiol, progesterone and testosterone on LH-RH release were observed when the steroid treatment was combined with that of LH-RH.

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.

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.

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