Ultradian Oscillations of Insulin Secretion in Humans
- From the Laboratoire des Régulations Physiologiques et des Rythmes Biologiques chez l’Homme, 67085 Strasbourg Cedex, France
Abstract
Ultradian rhythmicity appears to be characteristic of several endocrine systems. As described for other hormones, insulin release is a multioscillatory process with rapid pulses of about 10 min and slower ultradian oscillations (50–120 min). The mechanisms underlying the ultradian circhoral oscillations of insulin secretion rate (ISR), which arise in part from a rhythmic amplification of the rapid pulses, are not fully understood. In humans, included in the same period range is the alternation of rapid eye movement (REM) and non-REM (NREM) sleep cycles and the associated opposite oscillations in sympathovagal balance. During sleep, the glucose and ISR oscillations were amplified by about 150%, but the REM-NREM sleep cycles did not entrain the glucose and ISR ultradian oscillations. Also, the latter were not related to either the ultradian oscillations in sympathoagal balance, as inferred from spectral analysis of cardiac R-R intervals, or the plasma fluctuations of glucagon-like peptide-1 (GLP-1), an incretin hormone known to potentiate glucose-stimulated insulin. Other rhythmic physiological processes are currently being examined in relation to ultradian insulin release.
Footnotes
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Address correspondence and reprint requests to chantal.simon{at}medecine.u-strasbg.fr.
Accepted for publication 22 June 2001.
EEG, electroencephalographic; GLP-1, glucagon-like peptide-1; HF, high frequency; ISR, insulin secretion rate; LF, low frequency; NREM, non-rapid eye movement; REM, rapid eye movement; SWS, slow-wave sleep.
The symposium and the publication of this article have been made possible by an unrestricted educational grant from Servier, Paris.
