OBSERVATIONS ON A DITHIOCARBAMOYLHYDRAZINE AS AN INHIBITOR OF PITUITARY GONADOTROPHIC ACTIVITY

1963 ◽  
Vol 26 (3) ◽  
pp. 425-436 ◽  
Author(s):  
P. S. BROWN

SUMMARY A dithiocarbamoylhydrazine (ICI 33828) was injected s.c. into intact rats and mice. It usually caused a reduction in weight of the uterus or of the accessory organs in the male, but less commonly of the gonads. As little as 0·5 mg. daily for 4 days caused significant effects in adult female rats, while half this dose on alternate days retarded maturation in male rats. ICI 33828 was injected with exogenous gonadotrophin in three systems of assay and in some cases it modified the response to the gonadotrophin. This may not be due to a specific effect at the gonadal level but either to suppression of endogenous gonadotrophins in the test animals or to the effect of ICI 33828 on their general condition. Pituitary glands from male rats treated with ICI 33828 were assayed for follicle stimulating hormone (FSH) and found to contain significantly less than glands from control rats. This suggests that ICI 33828 acts by reducing the formation of pituitary gonadotrophin.

1972 ◽  
Vol 50 (8) ◽  
pp. 768-773 ◽  
Author(s):  
E. A. Ibrahim ◽  
B. E. Howland

The concentration of follicle-stimulating hormone (FSH) and luteinizing hormone (LH) in serum and pituitary glands was studied in intact female rats and rats that were ovariectomized on day 0 of the experiment and then starved or fed for 2, 4, 7, or 9 days. Ovariectomy resulted in enhanced rates of synthesis and release of FSH and LH as indicated by the significant (P < 0.01) rises in the concentration of both hormones in the pituitary gland and serum.Starvation resulted in a decrease in body and pituitary weight. The concentration of FSH and LH in pituitary glands of starved rats was higher (P < 0.05) than that in fed rats on days 7 and 9. The concentration of FSH and LH in serum of starved rats was increased after ovariectomy but the levels on days 7 and 9 were lower than those of fed rats.These results suggest that the synthesis of FSH and LH was enhanced in both starved and fed rats following ovariectomy while the rate of release of both hormones was decreased at 7 and 9 days of starvation in comparison with rats fed ad libitum.


1973 ◽  
Vol 58 (3) ◽  
pp. 547-554 ◽  
Author(s):  
L. CALIGARIS ◽  
J. J. ASTRADA ◽  
S. TALEISNIK

SUMMARY Serum follicle-stimulating hormone (FSH) concentration was found to be higher in neonatal female rats than in adults. The values increased to a maximum on day 15 and decreased thereafter. Ovariectomy soon after birth or at 5 days of age induced a significant rise in serum FSH concentration 9 days later. Administration of 10 μg oestradiol benzoate (OB) lowered FSH concentration in both intact and spayed animals. Progesterone (1 mg) injected 3 days after priming female rats with a single dose of 10 μg OB induced, on the same day, a significant rise in serum FSH concentration in animals older than 22 days of age. In younger animals progesterone reversed the effect of OB. The facilitatory effect of progesterone occurred when the hormone was given in the afternoon but not when it was given in the morning. Male rats, although showing the negative feedback effect of OB injection, failed to show the positive feedback effect of progesterone. It is concluded that the central nervous system—hypophysial mechanism responsible for FSH secretion is ready to function before puberty. In female rats initiation of puberty probably depends on the activation of that mechanism by appropriate facilitatory ovarian steroid signals.


1973 ◽  
Vol 59 (3) ◽  
pp. 599-604 ◽  
Author(s):  
HIROSHI NAGASAWA ◽  
REIKO YANAI ◽  
SAKAE KIKUYAMA ◽  
JUNICHI MORI

SUMMARY The serum and pituitary levels of prolactin, luteinizing hormone (LH) and follicle-stimulating hormone (FSH) were determined by radioimmunoassay in adult female rats treated neonatally with oestrogen and were compared with levels in normal cyclic rats at 90, 150 and/or 180 days of age. The serum level of prolactin was significantly higher and its pituitary content and concentration were lower in oestrogenized rats than in control rats at early prooestrus and on the 2nd day of dioestrus. The level of LH in the serum of oestrogenized rats was similar to the level in control rats at pro-oestrus and was higher than that of the controls at dioestrus. Pituitary levels of LH were lower in oestrogenized rats than in control rats at both pro-oestrus and dioestrus. The serum and pituitary levels of FSH in the oestrogenized rats were intermediate between the values found at dioestrus and at pro-oestrus in the controls. The results demonstrate that the pituitary of the neonatally oestrogenized female rat constantly secretes considerable amounts of these hormones.


1977 ◽  
Vol 74 (1) ◽  
pp. 143-144 ◽  
Author(s):  
J. A. MOGUILEVSKY ◽  
P. SCACCHI ◽  
L. RUBINSTEIN

Department of Neuroendocrinology, Centro de Investigaciones Médicas Albert Einstein (CIMAE), Luis Viale 2831, Buenos Aires, Argentina and *Department of Obstetrics and Gynecology, UCLA School of Medicine, Los Angeles, California, U.S.A. (Received 18 January 1977) It is generally accepted that the administration of androgens to female rats in the neonatal period suppresses cyclic gonadotrophin release and a tonic gonadotrophin release occurs (Barraclough, 1966; Gorski, 1971). The tonic or male gonadotrophin pattern characteristically shows higher levels of plasma and pituitary follicle-stimulating hormone (FSH) and serum prolactin compared with female rats (Johnson, 1967, 1971; Kragt & Ganong, 1968; Neill, 1972). In spite of the fact that the neonatal administration of androgens also induces changes in the reproductive physiology of adult male rats (Johnson & Witscht, 1963; Johnson, Yasuda & Sridharan, 1964; Morrison & Johnson, 1966), the effect of androgenization on gonadotrophin secretion in this sex is not clear. The purpose of the present study


1985 ◽  
Vol 231 (3) ◽  
pp. 785-787 ◽  
Author(s):  
C A Lamartiniere

Hepatic histidase activity in adult female rats is twice that in adult male rats. Hypophysectomy and thyroidectomy result in a significant increase in hepatic histidase activities in males, but not in females. This effect on histidase is reversed by the exogenous administration of tri-iodothyronine, but not by ectopic pituitary glands or purified pituitary hormones.


1963 ◽  
Vol 42 (2) ◽  
pp. 254-262 ◽  
Author(s):  
J. J. van der Werff ten Bosch ◽  
H. E. Swanson

ABSTRACT Adult female rats were given a normal diet, or a diet which contained 0.15% propylthiouracil. At the beginning of the experiment one half of the rats were left intact, whilst the others received an electrolytic basal midline lesion in the anterior hypothalamus. Of each of the four groups of rats, one half was killed after 14 days, the others after 28 days. It was found (both after 14 and after 28 days) that the presence of a lesion reduced the thyroid weight to approximately 75% of the value in intact rats on the same diet, which might be normal or contain propylthiouracil. Propylthiouracil caused thyroid enlargement (to 278% after 14 days and 352–360% after 28 days) in intact rats as compared with intact rats on a normal diet, and in lesioned rats as compared with lesioned rats on a normal diet. It is concluded that lesions cause a lowered steady state of the thyroid-pituitary feed-back system, but that this system responds normally to the alteration of the steady state caused by the propylthiouracil-induced block in thyroid hormone output.


Life Sciences ◽  
1985 ◽  
Vol 36 (9) ◽  
pp. 889-899 ◽  
Author(s):  
Henry M. Jones ◽  
Constance L. Wood ◽  
Michael E. Rush

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