Effect of insulin sensitivity on pulsatile insulin secretion.
OBJECTIVE
The aim of the study was to determine whether derangements in insulin pulsatility are related to the presence of insulin resistance or whether these changes occur only in non-insulin-dependent diabetes mellitus (NIDDM).


METHODS
The study included 26 obese, 11 NIDDM and 10 control subjects. The obese group was divided into a low insulin (plasma insulin <20 mU/l, OLI, 14 subjects) and a high insulin (OHI, 12 subjects) group. For pulsatility analysis blood was sampled every 2 min for 90 min. Pulsatility analysis was carried out using the PulsDetekt program. The insulin secretion randomness was quantified using interpulse interval deviation (IpID) and approximate entropy (ApEn). ApEn and ApEn normalized by s.d. of the individual insulin time series (nApEn) were calculated. Lower values of ApEn and IpID indicate more regular secretion. Homeostasis model assessment (HOMA) was used to quantify insulin sensitivity.


RESULTS
Insulin pulses were significantly less regular in the OHI and the NIDDM groups compared with the control and the OLI groups (control: ApEn 0.54+/-0.16, nApEn 0.69+/-0.19, IpID 2.53+/-0.99; OLI: ApEn 0.64+/-0.12, nApEn 0. 79+/-0.15, IpID 2.92+/-1.09; OHI: ApEn 0.88+/-0.07, nApEn 0.92+/-0. 07, IpID 3.95+/-0.84; NIDDM: ApEn 0.92+/-0.16, nApEn 0.99+/-0.09, IpID 4.41+/-0.53; means +/- s.d.). There was no difference in the pulse regularity between the OHI and the NIDDM groups.


CONCLUSIONS
Decrease in insulin sensitivity was correlated with the reduction of insulin secretion regularity. Therefore irregular insulin secretion is related to a reduction in insulin sensitivity, and it is not unique to NIDDM.
Zarković
M
M
Institute of Endocrinology, School of Medicine, University of Belgrade, Dr Subotića 13, 11000 Belgrade, Yugoslavia. mzarkov@eunet.yu
Cirić
J
J
Stojanović
M
M
Penezić
Z
Z
Trbojević
B
B
Dresgić
M
M
Nesović
M
M
D000328:Adult; D000465:Algorithms; D001786:Blood Glucose / Q000032:analysis; D003198:Computer Simulation; D003924:Diabetes Mellitus, Type 2 / Q000097:blood / Q000503:physiopathology*; D019277:Entropy; D006490:Hemostatics; D006801:Humans; D007328:Insulin / Q000032:analysis / Q000378:metabolism*; D007333:Insulin Resistance / Q000502:physiology*; D000078790:Insulin Secretion; D008875:Middle Aged; D008954:Models, Biological; D009765:Obesity / Q000503:physiopathology; D015282:Octreotide; D011673:Pulsatile Flow; D011863:Radioimmunoassay
D001786:Blood Glucose; D006490:Hemostatics; D007328:Insulin; D015282:Octreotide