Involvement of interleukin-1 in the inhibition of in vivo insulin release: possible role of adrenal glands.

The effect of recombinant human interleukin-1 beta (rhIL-1b) on in vivo insulin secretion was examined in intact and adrenalectomized (ADX) rats under conscious and pentobarbital anesthetized conditions. In conscious rats, rhIL-1b dose-dependently decreased blood glucose levels at 2 h in both groups and significantly inhibited insulin release only at doses of 1 and 10 micrograms/kg in ADX rats. Under pentobarbital anesthesia, rhIL-1b administration decreased blood glucose levels 2 h later in both intact and ADX rats and resulted in severe hypoglycemia in ADX rats. At 2 h later, rhIL-1b significantly suppressed insulin release by pentobarbital injection in both intact and ADX rats. It is concluded that rhIL-1b suppresses in vivo insulin secretion in conscious ADX and anesthetized rats.