In type II diabetic subjects, we previously demonstrated differences in the serum insulin, C-peptide, and glucagon response to ingestion of seven different protein sources when administered with 50 g of glucose. The response was smallest with egg white and greatest with cottage cheese protein. In the present study, we compared the responses to 50 g of the above two proteins ingested without glucose in normal male subjects. We also determined the proportion of each ingested protein converted to urea nitrogen. The incremental area response integrated over 8 hours for serum insulin, C-peptide, glucagon, α-amino-nitrogen (AAN), and urea nitrogen were all approximately 50% less following egg white. This was associated with a 50% smaller conversion of protein to urea. Overall, 70% of the cottage cheese but only 47% of the egg white protein could be accounted for by urea formation. Most likely the smaller hormonal response to egg white is due to poor digestibility of this protein.
Bibliographical noteFunding Information:
From the Metabolic Research Laboratory and the Section of Endocrinology. Metabolism, and Nutrition, VA Medical Center: and the Departments of Medicine, and Food Science and Nutrition, University of Minnesota, Minneapolis, MN. Supported by Merit Review Research Funds from the Veterans Administration, andfunds from the National Dairy Board, administered in cooperation with the National Dairy Council. Address reprint requests to Frank Q. Nuttall. MD, PhD. Chief, Section of Endocrinology, Metabolism, and Nutrition (1 I IG), VA Medical Cenier, Minneapolis, MN 55417. @ 1990 by W.B. Saunders Company. 00260495/90/3907-0015$03.00/0