AJP - Regulatory, Integrative and Comparative Physiology, Vol 261, Issue 3 548-R552, Copyright © 1991 by American Physiological Society
Normal food intake and growth in hyperprolactinemic rats
R. A. Adler and R. J. Krieg Jr
Endocrinology and Metabolism Section, McGuire Veterans Affairs Medical Center, Richmond, Virginia 23249.
Normal lactation, a state of chronic hyperprolactinemia, is often
accompanied by increased food intake. Two recent reports suggested that, in
rats, prolactin (PRL) administration or chronic endogenous PRL excess led
to increased food intake and growth. Similar methods of achieving augmented
circulating levels of PRL in rats have been employed in our laboratory.
Rats with extra anterior pituitary (AP) grafts under the kidney capsule
have chronically elevated circulating PRL levels. However, in several
experiments, weight gain, food intake, and fecal weight were the same in
AP-grafted rats and in control muscle-grafted rats. In addition, the
AP-grafted rat model was modified to demonstrate that PRL-induced increases
in adrenal glucocorticoids and decreases in estrogens did not provoke
alterations in eating behavior. Injection of homologous PRL for 8 days did
not increase weight gain in normal or hypophysectomized rats. These data
suggest that neither the chronic PRL excess caused by AP grafts nor the
acute PRL excess caused by rat PRL injections increases food intake or
weight gain.
