Interrelationships between dietary carbohydrates, B cell function and rate of ketogenesis during underfeeding in obese patients.
Six matched groups of obese patients underwent 3-week selective hypocaloric regimens which consisted of a 240 or 480 kcal/day liquid formula diets for groups 1-4 and an 800 kcal/day conventional diet for groups 5 and 6. Carbohydrate intake ranged from 19 to 112 g/day so that for each energy level two different amounts of carbohydrates were administered. Body weight loss was similar in groups 1-4 and significantly lower in groups 5 and 6. During treatment fasting serum insulin (but not serum C-peptide) levels and the daily urine excretion rate of C-peptide showed quite a similar fall in all groups. Fasting glucagon levels did not change. The rate of ketogenesis which developed during each nutritional treatment was inversely related to the amount of dietary carbohydrates; moreover, a significant correlation was found between percent variation of ketoacids and those of fasting IRI (r = -0.42; p less than 0.01) and glucose (r = -0.52; p less than 0.01) concentrations, but not with those of fasting C-peptide and its daily urine excretion rate. In conclusion, it seems that during underfeeding (1) low- and high-carbohydrate-containing regimens are substantially equipotent stimuli secretagogues of insulin secretion, and (2) carbohydrate (or glucose) availability affects ketogenesis even through noninsulin-mediated mechanisms.
Pasquali
R
R
Baraldi
G
G
Capelli
M
M
Patrono
D
D
Melchionda
N
N
D000328:Adult; D001786:Blood Glucose / Q000378:metabolism; D002096:C-Peptide / Q000097:blood; D004038:Diet, Reducing; D004040:Dietary Carbohydrates / Q000008:administration & dosage*; D002149:Energy Intake; D005215:Fasting; D005260:Female; D005934:Glucagon / Q000097:blood; D006801:Humans; D007328:Insulin / Q000097:blood*; D007657:Ketone Bodies / Q000097:blood*; D008297:Male; D009765:Obesity / Q000097:blood / Q000178:diet therapy*
D001786:Blood Glucose; D002096:C-Peptide; D004040:Dietary Carbohydrates; D007328:Insulin; D007657:Ketone Bodies; D005934:Glucagon