Prolactin secretion in lactating rats following chronic alcohol exposure: provocative tests with secretagogues

This study was done to examine the mechanism of action of alcohol in inhibiting suckling-induced prolactin release in the lactating rat. Alcohol (0.0, 1.0 or 2.0 g/kg body weight) was administered daily for 8 days from day 5 to 12 of lactation via an indwelling atrial catheter, implanted on day 3 of lactation. Following the administration of the initial alcohol dose, infusion was continued at rates required to maintain the blood alcohol levels (BALs) for four hours every day. Prolactin responses to sulpiride and TRH were tested on day 12. Alcohol administration for 8 days and maintaining the blood alcohol levels for four hours daily did not affect the basal or sulpiride and TRH-stimulated plasma prolactin release. Since the prolactin releasing capacity of pituitary lactotropes of the lactating rat is not compromised following chronic alcohol exposure, we conclude that alcohol does not act at the anterior pituitary level to inhibit the suckling induced prolactin release but probably acts by other mechanisms: either via the hypothalamic and/or higher central nervous system or by disrupting the neural impulse transmission, engendered at the nipples in response to suckling.