Blood pyruvate and lactate levels during oral and intravenous glucose tolerance tests in diabetes mellitus.

1. Blood pyruvate and lactate levels during oral and intravenous glucose tolerance tests are described in obese and non-obese non-diabetic, maturity-onset diabetic and insulin-requiring diabetic groups of women. 2. Mean fasting blood pyruvate levels were similar in non-diabetic, maturityonset diabetic and insulin-requiring diabetic subjects of similar degree of obesity. Mean levels were higher in the obese groups of non-diabetic and maturity-onset diabetic subjects compared to those of non-obese subjects of similar degree of glucose tolerance. 3. After oral glucose administration similar mean increases of blood pyruvate levels above the fasting base-line were found in non-diabetic and maturity-onset diabetic subjects matched for degree of obesity. 4. Peak oral glucose tolerance test blood pyruvate levels were generally delayed in the maturity-onset diabetic subjects and mean blood pyruvate levels were elevated above those of the non-diabetic subjects during the later stages of the test. Qualitatively similar changes occurred during intravenous glucose tolerance tests. 5. Mean blood lactate/pyruvate ratios were similar in non-obese and obese nondiabetic and maturity-onset diabetic groups of subjects and changed little after oral glucose administration.