The effects of somatostatin on calcitonin secretion were studied in ma
le Wistar albino rats. In anesthetized rats, the administration of syn
thetic somatostatin induced a reduction in the calcitonin content of t
he thyroid. In animals with destroyed central adrenergic neurons, the
effects of somatostatin were less visible. An intravenous injection of
somatostatin did not affect the baseline calcitonin level, but it did
prevent the rise in calcitonin concentration elicited by the intraven
ous administration of calcium gluconate.