Prolactin: a hormonal regulator of the neonatal tissue water reservoir.

Groups of newborn rabbits were treated with exogenous prolactin, with fluphenazine (a stimulant of endogenous prolactin secretion) with bromocriptine (a blocker of endogenous prolactin secretion), or with bromocriptine plus exogenous prolactin, and lean body hydration in these animals was compared with that of untreated controls. Animals treated with prolactin or fluphenazine retained more water than did the controls. Bromocriptine-treated animals retained less water than did the controls. Exogenous prolactin abolished the effect of bromocriptine.