Effect of prolactin administration and suppression on blood pressure and body fluid compartments in the rat.

Abstract

The effects of chronic hyper- and hypoprolactinemia on blood pressure (BP), body fluid compartments, and renal function in male rats were studied. Chronic hyperprolactinemia was induced by administration of ovine PRL (oPRL) over 7 days at a rate of 8.9 μg/h via an ip osmotic minipump. Hypoprolactinemia was induced by lergotrile mesylate (LM), administered at 10.0 μg/h via osmotic pump. In addition, several rates of oPRL administration (0.6, 2.9, 5.7, 11.3, and 22.7 μg/h) were studied. Total body water, extracellular fluid volume (ECF), and plasma volume were determined by dilution of 3H2O, 35SO4, and 51Cr-chloride, respectively. BP increased after oPRL administration at 0.6 μg/h (P < 0.001) and decreased after oPRL administration at 8.9 μg/h (P < 0.001) and 22.7 μg/h (P < 0.01). The oPRL (8.9 μg/h) -induced fall in BP was associated with an increased ECF (P < 0.05) and plasma volume (P < 0.05). Total body water was unchanged in all studies. Similar to the high dose oPRL administration, LM also lowered BP ...