Effects of high carbohydrate, high fat, or high protein diets on glucose oxidation by isolated intestinal epithelial cells of the chick.

A parallel study of 3-O-methyl glucose transport by everted intestinal sacs and [U-14C]glucose oxidation by isolated, dispersed intestinal cells was done in chicks (1) adapted to a high carbohydrate (HC), high fat (HF), or high protein (HP) diet for 2 weeks or (2) fasted up to 5 days. HF and HP diets significantly decreased both serosal : mucosal (S : M) distribution ratios of 3-O-methyl glucose by everted sacs and glucose oxidation by dispersed cells. The effects were more pronounced in HF diet-fed chicks. Fasting signficiantly increased the S : M ratio throughout a 5-day fasting period, whereas glucose oxidation was increased after a 1-day fast and was decreased after a 5-day fast. Feeding HC diet for 1 week to chicks adapted to HF diet restored both functions to control levels. Refeeding fasted chicks for 3 days also restored S : M ratio to control levels. Histological examination of tissues from various treatment groups revealed no obvious morphological differences. The results suggest that the functional changes described represent adaptive changes at the cellular level and that these changes are readily reversible.