The effects of injecting [D-Ser(But6] Des Gly-NH210 luteinizing hormone releasing hormone ethylamide in early, mid and late seasonal anoestrus on gonadotrophin secretion and luteal function in the ewe

ABSTRACT Long-term treatment with the potent and long-acting stimulatory luteinizing hormone-releasing hormone (LRH) analogue D-Ser(TBU)6-EA10-LRH was given to 4 healthy men to study its effects on pituitary gonadotrophin secretion and gonadal function. Five μg of the LRH agonist was self-administered sc once daily over 17 weeks. Weekly basal blood samples were obtained for determination of follicle-stimulating hormone (FSH), luteinizing hormone (LH), prolactin (PRL) and testosterone. The gonadotrophin responses to the LRH analogue were also determined during the treatment period. LRH tests were performed after treatment. Seminal fluid specimens were collected during and after treatment. A reduction of the basal serum gonadotrophin and testosterone levels were observed during the treatment period. The FSH and LH responses to the analogue were also diminished. After discontinuation of treatment the gonadotrophin and testosterone concentrations returned to pre-treatment levels within a week. The PRL levels and the seminal fluid specimens did not show any significant changes during the study period. The results suggest that chronic treatment with D-Ser(TBU)6-EA10-LRH has an inhibitory effect on the pituitary gonadotrophin secretion in healthy men. It seems likely that the reduced testosterone level is secondary to the diminished gonadotrophin secretion.

Download Full-text

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

Journal of Endocrinology ◽

10.1677/joe.0.0730037 ◽

1977 ◽

Vol 73 (1) ◽

pp. 37-52 ◽

Cited By ~ 15

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.

Download Full-text