Endocrinology, Vol 104, 390-395, Copyright © 1979 by Endocrine Society
Effects of hypophysectomy, thyroidectomy, and thyroxine on specific prolactin receptor sites in kidneys and adrenals of male rats
S Marshall, JF Bruni and J Meites
The effect of T4 on specific PRL binding in the kidneys and adrenals was
measured in intact, hypophysectomized, and thyroidectomized male rats. PRL
binding in the kidneys was reduced from 12.1 +/- 1.1% in the intact group
to 4.5 +/- 0.5% after hypophysectomy; 4-day replacement with T4 returned
PRL binding to intact values. T4 administered to intact rats significantly
increased PRL binding above intact values. Thyroidectomy reduced PRL
binding in the kidneys from 14.9 +/- 1.2% to 7.0 +/- 0.6%, and T4 treatment
restored PRL binding to intact values. PRL binding was measured at 2, 3, 5,
7, and 10 days after thyroidectomy in kidneys and found to decrease
progressively from 8.2+/-0.5% in the intact rats to 2.3+/-0.3% on day 10. A
single injection of T4 doubled PRL recetor binding in kidneys of
thyroidectomized rats at 12 h and returned binding to intact levels at 24
h. In contrast to the effects of T4 on kidney PRL binding, adrenal PRL
binding was only slightly altered by thyroidectomy and T4. These results
suggest that T4 has a specific role in regulating PRL receptors in the
kidneys but not in the adrenals. Since PRL receptors in the adrenals were
only slightly altered by thyroid status, it is believed that the changes in
kidney receptors represent a specific rather than a general metabolic
effect of T4.
