Preservation of insulin effects on glucose production and proteolysis during fasting

insulin effects on glucose production and proteolysis during fasting. Am. J. Physiol. 254 (Endocrinol. Metab. 17): E700-E707, 1988.-To determine whether fasting alters the ability of insulin to suppress endogenous glucose production or prote-olysis, isotopic flux measurements of glucose, leucine, cu-keto-isocaproate, and alanine were made in 13 normal volunteers after a 14-h (day 1) and an 84-h (day 4) fast. Using the “pancreatic clamp ” technique, we achieved small increments in plasma insulin concentrations, as well as constant and identical plasma hormone and glucose concentrations, on both study days in seven subjects. The remaining six subjects were infused with saline and served as controls. Leucine rate of appearance (an index of proteolysis) was greater on day 4 than on day 1 (P < 0.001) but decreased to equal values during the pancreatic clamp on each study day. During the pancreatic clamp, endog