Abstract
To explore the role of endogenous glucocorticoid in insulin secretion, the plasma
concentrations of insulin in the fasting state and in response to intravenous administration
of glucose were determined in adrenalectomized and sham-adrenalectomized rats. Adrenalectomy
produced a decrease in the fasting plasma insulin two days after the operation when
there was found no change in the blood glucose levels. Likewise, plasma insulin response
to glucose was clearly reduced in adrenalectomized rats, although there was no difference
among the two groups in increment of the blood glucose after the glucose load. At
this moment, a stimulatory action of insulin on glucose metabolism was rather decreased
in the adipose tissue from the adrenalectomized rats when compared with that from
the control rats. The pancreatic tissue from the adrenalectomized rats secreted much
less amount of insulin in response to perfused glucose not only in the early phase
but also in the second phase of release pattern. The pancreas from the adrenalectomized
rats treated with dexamethasone showed the opposite changes. These findings support
the hypothesis that the endogenous glucocorticoid may play a role in maintaining sensitivity
of the B cell to insulinogenic stimuli.
Key words
Glucocorticoids - Adrenalectomy - Insulin Secretion - Perfused Pancreas - Glucose
Metabolism
