ANDROGEN RECEPTORS IN THE RAT BRAIN, ANTERIOR PITUITARY GLAND AND VENTRAL PROSTATE GLAND: EFFECTS OF ORCHIDECTOMY AND AGEING

1979 ◽  
Vol 81 (1) ◽  
pp. 75-81 ◽  
Author(s):  
B. D. GREENSTEIN

Available high-affinity binding sites for 5α-dihydrotestosterone (DHT) were measured in cytosols obtained from the amygdala, hypothalamus, anterior pituitary gland and ventral prostate gland of 12-week-old rats at various times after orchidectomy, and in the corresponding tissues of 18-month-old male rats. It is suggested that the lower affinity of the DHT binding reaction in brain and ventral prostatic cytosols after orchidectomy or ageing respectively, may explain, at least in part, the changes in the responsiveness of the tissues to androgens.

1986 ◽  
Vol 108 (3) ◽  
pp. 399-403 ◽  
Author(s):  
R. L. Pérez ◽  
G. A. Machiavelli ◽  
M. I. Romano ◽  
J. A. Burdman

ABSTRACT Relationships among the release of prolactin, the effect of oestrogens and the proliferation of prolactin-secreting cells were studied under several experimental conditions. Administration of sulpiride or oestradiol released prolactin and stimulated cell proliferation in the anterior pituitary gland of adult male rats. Clomiphene completely abolished the rise in cell proliferation, but did not interfere with the sulpiride-induced release of prolactin. Treatment with oestradiol plus sulpiride significantly increased serum prolactin concentrations and the mitotic index compared with the sum of the stimulation produced by both drugs separately. Bromocriptine abolished the stimulatory effect of oestradiol on the serum prolactin concentration and on cell proliferation. In oestradiol- and/or sulpiride-treated rats, 80% of the cells in mitoses were lactotrophs. The remaining 20% did not stain with antisera against any of the pituitary hormones. The number of prolactin-secreting cells in the anterior pituitary gland significantly increased after the administration of oestradiol or sulpiride. The results demonstrate that treatment with sulpiride and/or oestradiol increases the proliferation and the number of lactotrophs in the anterior pituitary gland of the rat. J. Endocr. (1986) 108, 399–403


1987 ◽  
Vol 45 (6) ◽  
pp. 492-497 ◽  
Author(s):  
Michel Grino ◽  
Viviane Guillaume ◽  
Elias Castanas ◽  
Françoise Boudouresque ◽  
Bernard Conte-Devolx ◽  
...  

1970 ◽  
Vol 65 (1) ◽  
pp. 103-110 ◽  
Author(s):  
Kjell J. Tveter

ABSTRACT [6,7-3H] 17β-Oestradiol with a specific activity of 42.4 Ci/mmole was injected intramuscularly into three to four month old male rats, castrated three days previously. The radioactivity in liver, skeletal muscle, blood, the anterior pituitary gland, the seminal vesicles and in the different prostatic lobes was measured by liquid scintillation counting at different intervals after the administration. A high and prolonged uptake of radioactivity was found in the anterior pituitary gland. The uptake by the accessory sex organs was much lower, but significantly higher than that by skeletal muscle. The uptake by the prostate and the seminal vesicles in castrated animals was similar to that in non-castrated animals. The pattern of radioactivity uptake in the anterior pituitary gland of castrated male rats given [3H] testosterone was distinctly different from that after administration of [3H] 17β-oestradiol. There was a rapid elimination of radioactivity from the adenohypophysis after the administration of [3H] testosterone.


1982 ◽  
Vol 94 (1) ◽  
pp. 1-10 ◽  
Author(s):  
G. A. Jahn ◽  
G. A. Machiavelli ◽  
L. E. Kalbermann ◽  
I. Szijan ◽  
G. E. Alonso ◽  
...  

The effect of daily injections of sulpiride was compared with that of a single injection of the drug in male rats which had been treated with oestradiol diundecenoate for various periods of time. We studied the effect of the different treatments on weight of the pituitary gland, concentration of prolactin and incorporation of [3H]thymidine into DNA in the pituitary gland and on serum levels of prolactin. Administration of the oestrogen produced a marked increase in the synthesis of DNA at day 7. The stimulation diminished at day 21 and was not significant at day 45. The maximum increase in the concentration of prolactin in serum and pituitary glands was observed during the first 7 days (approximately 400 and 150% respectively) and in the weight of the anterior pituitary gland after 21 days of treatment (approximately 107%). A single injection of sulpiride markedly stimulated the release of prolactin and the synthesis of DNA at day 7. Both these effects diminished at day 21 and disappeared by day 45. Daily injections of sulpiride also produced similar changes in the release of prolactin and in the replication of DNA. The growth of the anterior pituitary gland was greater in this group than in the rats which had been treated with oestradiol diundecenoate only. After the end of treatment with oestrogen and sulpiride the pituitary weight and the concentration of prolactin in the anterior pituitary gland diminished together with levels of prolactin and oestrogen in serum. There was a good correlation between weight of the gland and serum levels of prolactin. The results further support the idea of a mechanism which controls the proliferation of lactotrophs in which the release of the hormone is accompanied by an increase in pituitary DNA synthesis.


1992 ◽  
Vol 55 (2) ◽  
pp. 199-203 ◽  
Author(s):  
Masahide Ohmichi ◽  
Kenji Hirota ◽  
Koji Koike ◽  
Hirohisa Kurachi ◽  
Shirou Ohtsuka ◽  
...  

1978 ◽  
Vol 76 (2) ◽  
pp. 211-218 ◽  
Author(s):  
K. K. SEN ◽  
K. M. J. MENON

Specific oestradiol binding to a receptor in nuclear and cytosol fractions of the rat anterior pituitary gland and pituitary responsiveness to gonadotrophin releasing hormone (GnRH) during the oestrous cycle have been studied. To accomplish this, both unoccupied and occupied oestradiol-binding sites in the cytosol and oestradiol-binding sites in the nucleus and total cell were measured during the oestrous cycle. The concentration of unoccupied and occupied sites and total oestradiol binding in the cytosol fluctuated during the cycle. At pro-oestrus, the concentration of cytosol receptor was diminished by about 40% and replenishment occurred during oestrus. On the other hand, a profound increase in concentrations of cellular and nuclear receptors occurred at pro-oestrus. Administration of GnRH significantly stimulated LH release at all stages of the cycle. The maximum stimulation of LH release by GnRH was observed at 13.00 h of pro-oestrus. From these studies, it is concluded that pituitary responsiveness to exogenous GnRH during pro-oestrus parallels the changes in the content of oestrogen receptors in the cytosol and nucleus.


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