This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Request Copyright Permission Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by CHEUNG, C. Y. Articles by WEINER, R. I. Search for Related Content PubMed PubMed Citation Articles by CHEUNG, C. Y. Articles by WEINER, R. I.

In Vitro Supersensitivity of the Anterior Pituitary to Dopamine Inhibition of Prolactin Secretion^*

CECILIA Y. CHEUNG and RICHARD I. WEINER

Department of Obstetrics, Gynecology and Reproductive Sciences, University of California, School of Medicine San Francisco, California 94143

Abstract

The sensitivity of pituitaries from medial basal hypothalamus (MBH)-lesioned rats to the inhibitory effects of dopamine and apomorphine on prolactin (PRL) secretion were studied in vitro. Anterior pituitary halves from ovariectomized control rats or ovariectomized rats lesioned for either 1 or 14 days were incubated in medium 199 and showed a linear release of PRL over the 3-h incubation period. Dopamine (10^-6 M) inhibited absolute or percentage of PRL release to the same extent from pituitaries of nonlesioned, 1-, and 14- day-lesioned animals. However, at 10^-8 M dopamine, the percent inhibition of PRL release from the pituitaries of the 14-day-lesioned group was significantly greater than from the nonlesioned and 1-day-lesioned groups. Apomorphine (5 x 10^-8 M) produced a greater absolute and percentage inhibition of PRL release from pituitaries of the 14-day-than from the pituitaries of 1-day-lesioned animals. No concentration of dopamine had a measurable effect on the concentration of pituitary PRL. However, 10^-8 M dopamine was effective in lowering total PRL (amount released plus amount remaining in the gland) only from pituitaries of 14-day-lesioned, but not of nonlesioned or 1-day-lesioned animals. This observation suggests that synthesis in addition to release might be involved in this supersensitivity phenomenon. The development of supersensitivity at the pituitary after long term removal of dopaminergic input, provides further evidence for the hypothesis that dopamine is a physiologic PRL release-inhibiting factor. (Endocrinology 102: 1614, 1978)

Footnotes

^* This work was supported in part by NIH grant HD-08924 and a Center grant from the Rockefeller Foundation.

To whom requests for reprints should be addressed

Received October 13, 1977.

This article has been cited by other articles:

				R. A. Depue, P. Arbisi, S. Krauss, W. G. Iacono, A. Leon, R. Muir, and J. Allen Seasonal Independence of Low Prolactin Concentration and High Spontaneous Eye Blink Rates in Unipolar and Bipolar II Seasonal Affective Disorder Arch Gen Psychiatry, April 1, 1990; 47(4): 356 - 364. [Abstract] [PDF]