Effects of acute and chronic protein depletion and of repletion on serum glycoprotein levels

¹ Department of Infectious Diseases, School of Medicine, University of California, Los Angeles, California

Adult, male, Sprague-Dawley rats weighing approximately 400 gm were fed either a protein-free or a 2% protein diet until they had lost 25% of their weight. Animals from each group were then killed. The remainder were repleted with a diet containing 25% protein. When they had regained their original weight, the rats were exsanguinated. The protein-bound carbohydrates and proteins of whole serum, and of the seromucoid, albumin and globulin fractions, as well as the hemoglobin and hematocrit values of blood were determined. Both acute and chronic depletion caused significant decreases in all serum constituents with the exception of the bound-carbohydrate of the albumin fractions. Upon repletion, significant increases over depletion levels occurred in total serum glycoprotein and protein concentrations due primarily to the elevation of the globulin fractions. Quantitative differences were observed between the response of the acute and chronically depleted groups to repletion but the pattern of change for the major serum fractions was similar for both groups.