Differential Effects of Protein Malnutrition and Ascorbic Acid Deficiency on Histidine Metabolism in the Brains of Infant Nonhuman Primates

Abstract

Male infant nonhuman primates ( M . nemestrina) born in captivity were used in the study. They were divided into three groups. The first group of three animals was fed a 20% casein diet and the second group of six monkeys received a 2.0% casein diet. The third group of four monkeys received a 20% casein diet totally devoid of ascorbic acid for 3.5 weeks before the diet was supplemented with ascorbic acid (20 mg/kg diet). All the diets were given to the animals in two daily rations of 100 glanimal. The monkeys fed a 2% casein diet failed to grow, and after about 3.5 months showed variable degrees of edema, hypoalbuminemia, evidence of psychomotor disturbance, depressed plasma levels of many essential amino acids, and other features consistent with the diagnosis of protein-energy malnutrition. Examination of the brains revealed significant alterations in the levels of histidine (+ 172%) and homocarnosine (+ 146%) in comparison with the control well-fed monkeys. Associated with the increase in brain histidine was a marked elevation of brain histamine level. Protein deficiency also led to poor brain retention of ascorbic acid but not to the same degree observed in the ascorbic acid-deficient animals. The latter group of animals, after receiving their diet for about 8 months, demonstrated a modest elevation in the plasma levels of most amino acids in comparison with controls. Ascorbic acid deficiency elicited a signifi-cant reduction (p < 0.01) in brain level of histidine, with

Cellular and molecular effects of malnutrition and their relevance to periodontal diseases

“…In malnutrition, particularly PEM and ascorbic acid deficiency states, there is a significant increase in tissue histamine levels (Enwonwu & Okolie 1983, Clemetson 1980. Ascorbic acid has an important role in detoxifying histamine in various conditions of stress (Clemetson 1989).…”