Dynamic aspects for inter-islet synchronization of oscillatory
insulin secretions.
Yao, Nan-Kuang, Liang-Wey Chang, Boniface Juisiang Lin, and Te-Son
Kuo.
Department of Electrical Engineering, Center for Biomedical
Engineering, and Graduate Institute of Clinical Medicine, National
Taiwan University, Taiwan, Republic of China
APStracts 4:0047E, 1997.
How do the oscillatory insulin secretions from numerous islets be
synchronized to result in an identifiable oscillation? We postulated
that a sudden increase in glucose concentration could best account
for the inter-islet synchronization. The perifusion with two parallel
chambers each containing 100 islets from the same rat was performed.
The glucose concentrations of two chambers were simultaneously
increased from 100 to 300 mg/dl in step function to examine the
synchronizing efficacy. Synchrony and regularity of insulin
oscillation were evaluated by cross-correlation and/or power spectral
analysis. Although the insulin had been in stable oscillation, we
found that the synchrony between two chambers and the regularity of
each chamber still were significantly improved after a sudden
increase of glucose level. However, the improved synchrony and
regularity were transient. They gradually slid toward a less rigorous
condition in a 15-hour long-term perifusion. We suggested that the
inter-islet synchronization of oscillatory insulin secretions could
be improved by a sudden increase of glucose level. The insulin pulses
were therefore enhanced to present their physiological effects.
Received 19 October 1996; accepted in final form 13 February
1997.
APS Manuscript Number E515-6.
Article publication pending Am. J. Physiol. (Endocrinol. Metab.).
ISSN 1080-4757 Copyright 1997 The American Physiological Society.
Published in APStracts on 5 March 1997