Effects of estrogen and ectopic pituitary transplants on the responsiveness of pituitary prolactin release to luteinizing hormone-releasing hormone and dopamine

Journal of Neuroendocrinology
A I EsquifinoV Chandrashekar

Abstract

Abstract The responsiveness of prolactin release to regulatory inputs depends on the functional state of the lactotrophs. In the present study, we have examined the effects of luteinizing hormone-releasing hormone (LHRH; 10(-7) or 10(-6) M) on the release of prolactin in vitro from hyperplastic pituitaries of estrogen-treated male Fischer rats, ectopic pituitary transplants and in situ pituitaries of grafted and control rats. The effects of dopamine (10(-8) or 10(-7) M) in this system were also examined. The extent of inhibition of prolactin release by dopamine was not related to the amounts of prolactin secreted under basal conditions or to plasma prolactin levels. LHRH significantly suppressed prolactin secretion in all groups but its effect was most pronounced in the ectopic pituitary transplants and in the hyperplastic pituitaries of animals after chronic exposure to estrogen followed by a period of recovery. Thus, the effects of LHRH on prolactin release appear to be related to the secretory activity and/or to the absolute or relative number of the lactotrophs.

References

Jun 1, 1975·Proceedings of the Society for Experimental Biology and Medicine·M Hill-Samli, R M MacLeod
Jun 1, 1986·The Journal of Clinical Endocrinology and Metabolism·V Mais, S S Yen
Jan 1, 1981·Annual Review of Pharmacology and Toxicology·J Meites, W E Sonntag
Jan 1, 1983·Annual Review of Physiology·D A LeongJ D Neill
Jul 1, 1984·Proceedings of the National Academy of Sciences of the United States of America·K A Elias, R I Weiner

Related Concepts

Dopamine
Estrogens
Hyperplasia
Gonadorelin
Pituitary Gland
Prolactin
Basal
Pituitary hormone preparation
In Situ
Ectopic (Qualifier Value)

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