The Effect of Estradiol Benzoate on the Pituitary Responsiveness to LH-RH in Male and Female Rats

1974 ◽  
Vol 15 (3-4) ◽  
pp. 182-188 ◽  
Author(s):  
J.A.M.J. van Dieten ◽  
J. Steijsiger ◽  
J. Dullaart ◽  
G.P. van Rees
Keyword(s):  
Estradiol Benzoate ◽  
Female Rats ◽  
Male And Female ◽  
Male And Female Rats ◽  
Lh Rh

DISSOCIATION IN THE REGULATION OF LUTEINIZING HORMONE AND FOLLICLE-STIMULATING HORMONE IN A HYPERPROLACTINAEMIC RAT MODEL: INTERRELATIONSHIPS BETWEEN GONADOTROPHIN AND PROLACTIN CONTROL

1981 ◽  
Vol 90 (1) ◽  
pp. 41-51 ◽  
Author(s):  
J. A. F. TRESGUERRES ◽  
A. I. ESQUIFINO
Keyword(s):  
Positive Feedback ◽  
Follicle Stimulating Hormone ◽  
Female Rats ◽  
Male And Female ◽  
Male And Female Rats ◽  
Oestradiol Benzoate ◽  
Female Wistar Rats ◽  
Pituitary Glands ◽  
Lh Rh ◽  
Lh Releasing Hormone

Male and female Wistar rats were made hyperprolactinaemic by grafting two pituitary glands of litter-mate donors under the kidney capsule at 30 days of age. Other animals were sham-operated at the same age to serve as controls. Plasma levels of prolactin, LH and FSH were measured by double-antibody radioimmunoassay. Basal preoperative prolactin levels of ∼ 10 ng/ml increased after the transplantation in both male and female rats, reaching values of ∼ 180 ng/ml. Levels of LH were significantly reduced in these hyperprolactinaemic rats, whereas an increase in FSH values was seen. After administration of LH releasing hormone (LH-RH) a reduced LH response was seen but there was no response of FSH to LH-RH or even a decrease in FSH values. Prolactin levels were also reduced by LH-RH injection. Although an increase in prolactin levels was observed in control animals after a challenge with oestradiol benzoate, reduced increments were seen in experimental animals. The positive feedback effect of oestradiol benzoate on LH in females was reduced in pituitary-grafted rats but a potentiation of the FSH positive feedback could be clearly detected. This study suggests a dissociation of LH and FSH regulation in hyperprolactinaemia.

Evaluation of biological activities of new LH-RH antagonists (T-series) in male and female rats

2009 ◽  
Vol 41 (1) ◽  
pp. 66-73 ◽  
Author(s):  
JACEK PINSKI ◽  
TETSU YANO ◽  
TAMAS JANAKY ◽  
ATTILA NAGY ◽  
ATTILA JUHASZ ◽  
...  
Keyword(s):  
Biological Activities ◽  
Female Rats ◽  
Male And Female ◽  
Male And Female Rats ◽  
Lh Rh

THE PITUITARY AND ADRENAL RESPONSES TO ADMINISTRATION OF OESTRIOL IN GONADECTOMIZED RATS

1961 ◽  
Vol 38 (1) ◽  
pp. 50-58 ◽  
Author(s):  
N. E. Borglin ◽  
L. Bjersing
Keyword(s):  
Pituitary Gland ◽  
Adrenal Cortex ◽  
Clinical Experience ◽  
Uterine Cervix ◽  
Morphological Changes ◽  
Physiological Significance ◽  
Female Rats ◽  
Experimental Conditions ◽  
Male And Female ◽  
Male And Female Rats

ABSTRACT Oestriol (oestra-1,3,5(10)-triene-3,16α,17β-triol) is a weakly oestrogenic substance which, however, in contrast to what was formerly believed, is of physiological significance. Its effect is localized largely to the uterine cervix and vagina. Clinical experience argues both for and against an effect on the pituitary gland. This investigation is concerned with the morphological changes in the pituitary gland and adrenal cortex of gonadectomized male and female rats after the injection of oestriol. It was found that oestriol has the same type of action on these glands as other oestrogens, but under the experimental conditions used, this effect proved much weaker than that produced by oestradiol (oestra-1,3,5(10)-triene-3,17β-diol).

INDUCTION OF GOITRE BY PTU OR KClO4 IN MALE AND FEMALE RATS. EFFECT OF GONADECTOMY

1973 ◽  
Vol 74 (1) ◽  
pp. 88-104 ◽  
Author(s):  
T. Jolín ◽  
M. J. Tarin ◽  
M. D. Garcia
Keyword(s):  
Iodine Content ◽  
High Plasma ◽  
Disc Electrophoresis ◽  
Female Rats ◽  
Male Rats ◽  
Adult Rats ◽  
Male And Female ◽  
Glucose Levels ◽  
Male And Female Rats ◽  
Tsh Levels

ABSTRACT Male and female rats of varying ages were placad on a low iodine diet (LID) plus KClO4 or 6-propyl-2-thiouracil (PTU) or on the same diet supplemented with I (control rats). Goitrogenesis was also induced with LID plus PTU in gonadectomized animals of both sexes. The weight of the control and goitrogen treated animals, and the weight and iodine content of their thyroids were determined, as well as the plasma PBI, TSH, insulin and glucose levels. The pituitary GH-like protein content was assessed by disc electrophoresis on polyacrylamide gels. If goitrogenesis was induced in young rats of both sexes starting with rats of the same age, body weight (B.W.) and pituitary growth hormone (GH) content, it was found that both the males and females developed goitres of the same size. On the contrary, when goitrogenesis was induced in adult animals, it was found that male rats, that had larger B.W. and pituitary GH content than age-paired females, developed larger goitres. However, both male and female rats were in a hypothyroid condition of comparable degree as judged by the thyroidal iodine content and the plasma PBI and TSH levels. When all the data on the PTU or KClO4-treated male and female rats of varying age and B.W. were considered together, it was observed that the weights of the thyroids increased proportionally to B.W. However, a difference in the slope of the regression of the thyroid weight over B.W. was found between male and female rats, due to the fact that adult male rats develop larger goitres than female animals. In addition, in the male rats treated with PTU, gonadectomy decreased the B.W., pituitary content of GH-like protein and, concomitantly, the size of the goitre decreased; an opposite effect was induced by ovariectomy on the female animals. However, when goitrogenesis was induced in weight-paired adult rats of both sexes, the male animals still developed larger goitres than the females. Among all the parameters studied here, the only ones which appeared to bear a consistent relationship with the size of the goitres in rats of different sexes, treated with a given goitrogen, were the rate of body growth and the amount of a pituitary GH-like protein found before the onset of the goitrogen treatment. Moreover, though the pituitary content of the GH-like protein decreased as a consequence of goitrogen treatment, it was still somewhat higher in male that in female animals. The present results suggest that GH may somehow be involved in the mechanism by which male and female rats on goitrogens develop goitres of different sizes, despite equally high plasma TSH levels.

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