AJP - Endocrinology and Metabolism, Vol 242, Issue 2 127-E136, Copyright © 1982 by American Physiological Society
Circadian profiles of insulin receptors in insulin-dependent diabetics in usual and poor metabolic control
O. Pedersen, E. Hjollund, H. O. Lindskov, H. Beck-Nielsen and J. Jensen
We have characterized the 24-h changes of insulin receptors on erythrocytes
from patients with insulin-dependent diabetes of long duration. These
diabetics were studied both in usual and poor metabolic control. Moreover,
we have examined daytime changes of insulin receptors on monocytes from
newly discovered diabetics. In both erythrocyte and monocyte studies,
diabetics were compared to healthy controls. At insulin tracer
concentration, insulin receptor binding to erythrocytes from diabetics in
usual control and normal volunteers underwent a statistically significant
diurnal variation with high binding values in the early morning, low
daytime values with a nadir in the late afternoon, and a peak around
midnight. Even diabetics in poor metabolic control due to insulin
deprivation had preserved a similar 24-h rhythm of erythrocyte insulin
receptors. Insulin receptor binding to monocytes at insulin tracer
concentration declined significantly during the day both in newly
discovered diabetics and in healthy controls. The mechanisms responsible
for the acute phase changes of insulin-receptor binding are unknown, but
the receptor changes seem related to the fed state. Moreover, analysis of
the temporal interrelationship between erythrocyte insulin binding and
plasma insulin concentration in diabetics during the 24-h period suggests
that in these patients insulin may be one of the factors determining the
rapid insulin receptor regulation.
