Diabetes, Vol 36, Issue 4 447-453, Copyright © 1987 by American Diabetes Association
Urine C-peptide as index of integrated insulin secretion in hypocaloric states in obese human subjects
JF Yale, LA Leiter and EB Marliss
To determine the effects of different hypocaloric diets on insulin secretion, 24-h urine C-peptide was measured in 11 obese subjects on a weight-maintaining baseline diet, and the results were compared with values obtained during 14-day periods of diets containing 400 kcal/day of only protein (n = 6) or glucose (n = 5), followed by 14 days of fasting and 14 days of refeeding on 800-1000 kcal/day. A significant positive correlation between total caloric intake and urine C-peptide excretion was found once the C-peptide excretion reached steady state after several days on each diet. Multiple regression analysis showed no contribution of body weight to urine C-peptide during the different diets. In contrast, a significant correlation was found between body weight and urine C-peptide in the fasting state. A marked and identical decrease of approximately 75% in urine C-peptide occurred over the first 5-7 days of the two 400-kcal diets, followed by a further decrease during fasting to 5% of baseline values. Refeeding was associated with a progressive increase. Plasma insulin and C-peptide followed the same trends as found for urine C-peptide, although the magnitude of change was much smaller. C-peptide clearance was not assessed because of the variation in plasma levels on eating meals. However, the same responses were found when C-peptide excretion was factored for creatinine excretion. Thus, the major determinant of urine C-peptide excretion appears to be food intake, and adaptations take 5-7 days to reach steady state.(ABSTRACT TRUNCATED AT 250 WORDS) This article has been cited by other articles:
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