Effect of chronic ingestion of ethanol on in vitro uptake of lipids and glucose in the rabbit jejunum

This study was undertaken to determine the effect of chronic feeding of ethanol on the in vitro jejunal uptake of lipids and glucose. The first group of rabbits was fed ad libitum (CAL); the food intake of a second control group [weight control (WC)] was restricted to match their gain in body weight with that of a chronically ethanol-fed group (ETH); and the food intake of a third control group [food control (FC)] was restricted to match the food intake with that of ETH. There was a marked decline in cholesterol uptake in WC and FC compared with CAL, and cholesterol uptake in ETH was intermediate between the higher value in CAL and the lower value in WC and FC. The uptake of fatty acids 4:0-12:0 was similar in the CAL, FC, WC, and ETH groups, both when the bulk phase was stirred and unstirred; the uptake of fatty acids 16:0 and 18:0 was lower in WC and FC than in CAL; and the uptake of fatty acids 14:0, 16:0, and 18:0 was even lower in ETH. The uptake of a homologous series of fatty alcohols was greater in WC and ETH than in CAL at five different rates of stirring of the bulk phase. When the uptake of fatty acids 6:0-12:0 was corrected for unstirred layer resistance, a linear relation was noted between fatty acid chain length and the natural logarithm of rate of uptake/aqueous diffusion coefficient, and the steeper slope in WC and ETH than in CAL represented a higher incremental change in free energy. Glucose uptake was similar in CAL, WC, and FC but was greater in ETH from 5 to 40 mM glucose. These studies demonstrate that 1) weight restriction, food restriction, and chronic ethanol feeding are associated with a change in the effective resistance of the unstirred layer and in the passive permeability properties of the rabbit jejunum, and 2) ethanol has a differential effect on passive permeation of short-, medium-, and long-chain fatty acids and cholesterol.