Lipid absorption in the young of protein-deficient rats.

The effect of reduced protein in the diet during pregnancy on the subsequent absorption of triolein and of oleic acid which were infused into the intestine of the young was studied. Pregnant rats were fed diets containing either 24% or 4% casein as the sole source of protein. Control and prenatally protein-deprived (PPD) young were studied at birth before and after suckling, and at 4, 8, and 12 days. Both body weight and the weight and length of intestine were reduced in PPD young. Uptake of triolein from the lumen and retention in enterocytes increased on suckling in newborn control pups, but the amount transferred from or metabolized by the cells did not change. In suckled PPD young, transfer of triolein increased through the enterocyte as well. Unsuckled PPD pups had reduced absorption and retention per enterocyte, per g body weight, per cm gut, and in total. In intestines of control and PPD suckled newborn and postnatal pups, absorption per cell did not differ. Blood lipid levels were increased markedly between 0 and 14 days and tended to decrease to newborn levels by 12 days in both diet groups. Oleic acid absorption in newborn and 12-day PPD pups were reduced in total, per g body weight and per cm of gut. The individual enterocytes were shown to be equally capable of absorption and transfer of triolein and oleic acid. Differences in absorption are related primarily to the numbers of absorptive cells.