Abnormalities in the ultradian oscillations of insulin secretion and glucose levels in type 2 (non-insulin-dependent) diabetic patients.
To investigate the temporal organization of insulin secretion and glucose concentration during fasting in Type 2 (non-insulin-dependent) diabetes mellitus, we studied seven patients with Type 2 diabetes, eight obese non-diabetic control subjects and eight normal weight non-diabetic subjects. Blood sampling for glucose, insulin and C-peptide was performed at 15-min intervals during a 24-h period of fasting for the diabetic and the obese control subjects and during an 8-h fasting period for the normal subjects. Insulin secretion rates were calculated from the peripheral C-peptide concentration profiles. Ultradian oscillations of glucose levels and insulin secretion rates were evident during fasting in all subjects. An additional study with blood sampling at 2-min intervals for 8 h further indicated that this ultradian periodicity is expressed independently of rapid 10-15 min insulin oscillations. There were no differences between diabetic and non-diabetic subjects in the frequency of the ultradian oscillations of insulin secretion (which averaged 12-15 oscillations per 24 h) and in the rate of concomitancy of oscillations of insulin secretion with oscillations in glucose levels, which averaged 63-65%. The relative amplitudes of both the insulin and glucose oscillations were also similar in diabetic and nondiabetic subjects. The major abnormality in patients with Type 2 diabetes was evidenced by spectral analysis, and confirmed by calculations of the distributions of inter-pulse intervals. It consisted of a slowing of the glucose oscillations, without a similar slowing of the oscillations in insulin secretion.(ABSTRACT TRUNCATED AT 250 WORDS)
Sturis
J
J
Department of Medicine, University of Chicago, Illinois.
Polonsky
K S
KS
Shapiro
E T
ET
Blackman
J D
JD
O'Meara
N M
NM
van Cauter
E
E
D000204:Activity Cycles; D001786:Blood Glucose / Q000378:metabolism*; D002096:C-Peptide / Q000097:blood; D003924:Diabetes Mellitus, Type 2 / Q000097:blood / Q000503:physiopathology*; D005215:Fasting; D005260:Female; D006801:Humans; D007328:Insulin / Q000097:blood / Q000378:metabolism*; D000078790:Insulin Secretion; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000097:blood / Q000503:physiopathology; D012016:Reference Values
D001786:Blood Glucose; D002096:C-Peptide; D007328:Insulin