CHANGES IN INTESTINAL AND SERUM ALKALINE PHOSPHATASE LEVELS DURING ABSORPTION OF CERTAIN AMINO ACIDS

Abstract

After force-feeding fasted male albino rats with solutions of amino acids it was observed that:(a) Intestinal alkaline phosphatase levels were significantly increased after ingestion of glycine, leucine, threonine, serine, glutamic acid, methionine, arginine, and large doses of glycine – glutamic acid – histidine mixtures, while a decrease was noted after force-feeding tryptophan.(b) Serum alkaline phosphatase activity was stimulated by solutions of glycine, histidine, and glutamic acid when each amino acid was given singly and even more when a mixture of these three amino acids was force-fed. Methionine on the other hand produced a highly significant depression of the activity of this enzyme.(c) Serum inorganic phosphorus levels were significantly decreased after ingestion of glycine, leucine, serine, threonine, methionine, glutamic acid, histidine, phenylalanine, tyrosine, and tryptophan.(d) Serum α-amino nitrogen concentration was increased in all cases except with cystine and lysine, when no change was observed, whereas arginine produced a highly significant drop, attributed to stimulation of urea cycle.(e) The α-amino nitrogen concentration of intestinal homogenates was increased after force-feeding glycine, leucine, cystine, methionine, glutamic acid, lysine, histidine, phenylalanine, and large amounts of glycine – histidine – glutamic acid mixtures.