Splanchnic amino acid pattern in genetic and dietary obesity in the rat.

The study of intestinal and hepatic uptake of amino acids by obese rats has been the main objective of this work. The obese animals used were either from genetic or from nutritional basis. In fed state, the intestinal release of amino acids was higher in obese animals than in lean ones (around the double values), but nutritionally and genetically obese rat showed a related pattern, specially for the case of alanine (increased release in relation to controls by a factor of 10). The higher alanine release by intestine is not reversed by 12-h food deprivation. The hepatic availability was also higher in obesity models than in lean animals (increases over 30%). However, the hepatic uptake was increased in genetically obese animals (more than 35%) and decreased in nutritionally obese animals (more than 40%), especially due to alanine uptake (2419, 1100 and 3794 nmols/min/g protein in lean, Diet-ob and fa/fa animals respectively). In obese animals the food deprivation tended to normalize the hepatic uptake of alanine. The differences in alanine uptake between both types of obesity may reflect the differences of urea synthesis.