American Journal of Clinical Nutrition, Vol 26, 1287-1302, Copyright © 1973 by The American Society for Clinical Nutrition, Inc.

Protein—energy deficiency in nonhuman primates: biochemical and morphological alterations

¹ From the Center for Research in Oral Biology and Department of Oral Biology, University of Washington (SC-90), Seattle, Washington 98195

Young pigtail monkeys fed a 2% casein diet in restricted amounts for a period of approximately 3 months developed many features consistent with the syndrome of protein-calorie malnutrition found in deprived children. Among the prominent biochemical findings in the malnourished monkeys compared with the pair-fed control animals were marked reduction in serum albumin concentration (–25%), profound elevation in plasma corticosteroid level (+132%), distorted free amino acid profiles in liver and serum, and disaggregation of liver polyribosomes with associated impairment of liver protein biosynthesis in a cell-free system. Histologic evaluation of the malnourished animals revealed extensive fatty metamorphosis of the liver, atrophy of the Malpighian corpuscles of the spleen, thyroid follicles lined by flat or low cuboidal epithelial cells, and marked atrophy of the adrenal cortex with conspicuous loss of lipid from the zona fasciculata. The histological changes in the thyroid gland were suggestive of impaired secretory activity. It was concluded that the clinical picture of severe protein-calorie malnutrition might represent the final outcome of a breakdown in the ability of the endocrine system to regulate cellular and metabolic activities in the face of dwindling supply of essential food nutrients.