Intestinal lymph formation and fat absorption: stimulation by acute ethanol administration and inhibition by chronic ethanol administration and inhibition by chronic ethanol feeding

Abstract

The acute administration of ethanol, either in lipid emulsions administered intraduodenally or in liquid diets given by gastric tube, increased the flow of intestinal lymph and the output of proteins and dietary lipids into the lymph, mainly in the 1st hr after administration. During this time, the intraduodenal administration of ethanol (0.75 g per kg of body weight), without exogenous lipids, increased the flow of lymph without changing the lymph lipid output. Stimulation of the lymph flow with neostigmine or by increasing the fluid load also enhanced the output of lymph proteins and the transport of exogenous lipids from the intestinal lumen into the lymph. To study the chronic effects of ethanol, rats were pair-fed liquid diets containing either ethanol (36% of calories) or isocaloric carbohydrate for 3 to 4 weeks. Thereafter, the lymph changes were measured after administration of equal lipid loads with and without ethanol. The administration of an acute ethanol dose to rats chronically fed alcohol moderately increased the lymph flow, but did not change the output of dietary lipids. Furthermore, rats chronically fed alcohol responded to a dietary challenge devoid of ethanol with increases in both lymph flow and dietary lipid output which were not as great as those of pair-fed controls. Thus, acute ethanol administration has a marked stimulatory effect both on the formation of intestinal lymph and on the transport of deitary fat. By contrast, chronic ethanol feeding inhibits these acute effects of ethanol, and, in addition, appears to have moderate inhibitory effect on lipid absorption.