An investigation into the effects of chronic ethanol feeding on hepatic mixed protein synthesis in immature and mature rats.

1. The response of the liver to chronic ethanol feeding was investigated in sexually immature (85 g) and sexually mature (280 g) male Wistar rats. Rats received a nutritionally adequate liquid diet ad libitum, in which ethanol comprised 36% of total calories, for up to 6 weeks. Controls were pair-fed the same liquid diet in which ethanol was substituted by isocaloric glucose. 2. In immature rats, total hepatic protein, RNA and DNA contents were reduced by 12-23%. The amount of RNA, relative to protein or DNA, was also decreased by 11-12%, though the amount of protein relative to DNA was unaltered. In mature rats, no change in total hepatic protein and DNA contents were observed, though total RNA, RNA/protein ratio, RNA/DNA ratio and the amount of protein relative to DNA was reduced by 7-18%. 3. Rates of protein synthesis were measured with a flooding dose of L[4-3H]-phenylalanine without anaesthesia or surgical stress. In both immature and mature rats the fractional and absolute rates of hepatic protein synthesis and protein synthesis relative to DNA were reduced by approx 25%.