AN INVESTIGATION OF THE EFFECTS OF INTERLEUKIN-1-BETA ON PLASMA ARGININE-VASOPRESSIN IN THE RAT - ROLE OF ADRENAL-STEROIDS

While the effects of cytokines on the hypothalamopituitary-adrenal axis have received a great deal of attention in recent years the effects of cytokines on posterior pituitary hormone release has been less well characterized. In the present study we have investigated the effects of a single i.p. injection of interleukin (IL)-1 beta on circulating levels of vasopressin (AVP) in the rat. We have found that the ability of IL-1 beta to increase plasma AVP is strongly influenced by circulating levels of glucocorticoid steroids. IL-1 beta did not affect plasma AVP in sham-operated control animals over the 4 h period of study. In contrast, following adrenalectomy we were able to stimulate AVP substantially with increases over the 4 h period. This effect was reduced by treatment of adrenalectomized rats with a low dose of dexamethasone and abolished with a high dose. These data suggest an inverse relationship between circulating levels of glucocorticoids and the ability of IL-1 beta to stimulate plasma AVP.