Effects of premature weaning on the metabolic response to dietary sucrose in adult rats.

Male, Sprague-Dawley rats were weaned prematurely (postnatal day 17) to a starch-based diet. At the age of 182 days, half of the rats were fed for 14 days a diet in which sucrose supplied 40% of the energy. Early weaning led to increases in the activities of hepatic glucose-6-phosphate dehydrogenase (G6PD) and malic enzyme (ME). Compared with spontaneously weaned rats, prematurely weaned animals also showed increases in hepatic lipogenesis in vivo and in liver cholesterol levels. However, early weaning did not influence intraperitoneal glucose tolerance, plasma cholesterol concentrations or the activities of hepatic ketohexokinase (KHK), fructose-1-phosphate aldolase (FIPA) and triokinase (TK). Sucrose feeding led to deterioration of glucose tolerance and to enhanced hepatic lipogenesis in vivo. Sucrose-fed rats also showed increases in the total activities of hepatic G6PD, ME, KHK, FIPA and TK. There was a positive interaction in effects on liver size between early weaning and dietary sucrose. In general, however, there were no differences between prematurely and normally weaned rats in their responses to sucrose. The results did not support the idea that dietary adaptations in early life alter the manner in which adult rats respond to dietary stimuli.