Evaluation of lactational parameters after alcohol administration for four days during early or midlactation in the rat

Abstract

This study was conducted to examine the effects of alcohol administered for 4 days during early lactational (days 5 to 8; experiment I) or midlactational (days 9 to 12; experiment II) stage in the rat on various lactational parameters. Litter size was adjusted to eight on day 2, and dams were implanted with an atrial catheter on day 3 (experiment I) or day 7 (experiment II). From days 5 to 8 in experiment I and days 9 to 12 in experiment II, dams were infused with saline (control rats) or alcohol in saline solutions (1.0 and 2.0 g/kg body weight; experimental groups). Blood alcohol levels (BALs) achieved after infusion of the initial doses were maintained for 4 hr daily by continuing infusion. To control for the reduced food intake in the high dose alcohol group, one control group and the group given 1.0 g/kg of body weight alcohol were pair-fed to the 2.0 g/kg body weight alcohol group. On day 8 (experiment I) or day 12 (experiment II), pups were separated from the dam at 0800 hr, and an extension was attached to the catheter. Alcohol or saline was infused, and the BALs achieved after infusion of initial doses were maintained for 4 hr. After removal of a baseline blood sample, pups were returned to dams, and additional blood samples were taken for prolactin measurement 10, 30, 60, and 120 min after suckling started. Suckling latency and milk consumed during the 120 min of suckling were measured. Litters were weighed every other day from days 2 to 21. In both studies, suckling-induced prolactin was inhibited by alcohol. Milk consumed by the pups during the 2-hr period was lower for alcohol groups, compared with control. The suckling latencies were comparable among groups. Litter weights showed no alcohol dose effect. In summary, based on the results from our previous and present studies, we conclude the following: alcohol administered for 1, 4, or 8 days inhibited suckling-induced prolactin release in lactating rats. During a 2-hr test period after alcohol administration, milk consumed by pups was not adversely affected after alcohol administration for 1 day. Whereas, 4 or 8 days of administration had a significant effect. The adverse effect of alcohol on litter growth, however, was evident only after 8 days of alcohol administration. Thus, the detrimental effects of alcohol on different lactational parameters seem to be correlated to the duration of alcohol administration to dams during lactation.