Protein-calorie malnutrition: Effect of deficient diets on enzyme levels of jejunal mucosa of rats

Abstract

1. The effects of low-protein and protein-free diets on the levels of disaccharidase, peptidase and aldolase activities in the jejunal mucosa of rats were studied.2. Maltase, palatinase and sucrase activities increased significantly after both types of feeding, although there was an initial fall with the protein-free diet.3. The rise in lactase levels was, however, not so marked.4. Glycyl-glycine and glycyl-leucine dipeptidase levels fell consistently with both diets.5. Aldolase activities were generally unaltered, but tended to fall if the period of low-protein feeding was prolonged.6. Enzyme levels rapidly returned to normal when the rats were given a normal diet after a period on a protein-deficient one.7. It is suggested that the rise in disaccharidase and fall in peptidase levels are adaptive changes to the high-carbohydrate, low-protein diet, with diminished enzyme synthesis, due to lack of nitrogen, contributing to the lowered peptidase activities. The relevance of these results to disaccharide intolerance in chronic malnutrition, kwashiorkor and gastro-intestinal infection is discussed.