EFFECT OF ESTROGEN AND NEUROLEPTICS ON PROLACTIN SECRETION AND IMMUNOREACTIVE PROLACTIN CELLS

The use of estrogen and dopamine receptor antagonists is associated wi th elevated prolactin levels and, in rats, chronic estrogen treatment is also associated with lactotroph proliferation. In this study, halop eridol, fluphenazine, sulpiride and metoclopramide, alone or combined with estradiol, were administered to Wistar rats. Pituitary weight, se rum prolactin levels and percent of immunoreactive prolactin cells in the anterior pituitary glands were determined at the end of 60 days of treatment. The pituitary weight of rats treated with estrogen alone o r in combination with other drugs was significantly higher than the co ntrol group. The serum prolactin level was higher than the upper confi dence limit in all but three of the 90 treated rats. While in the cont rol group the percent of immunoreactive prolactin cells was 20%, admin istration of the neuroleptic drugs and metoclopramide increased this p ercent to approximately 30%, and estrogen alone or in combination with one of the neuroleptic drugs increased it to approximately 40%. The r esults presented here demonstrate the relationship between prolactin s ecretion and prolactin cell number when different neuroleptics and rel ated drugs are used.