T. Watanabe et al., FEBRILE RESPONSES INDUCED IN ADRENALECTOMIZED RATS BY ADMINISTRATION OF INTERLEUKIN-1-BETA OR PROSTAGLANDIN E(2), Journal of physiology, 484(3), 1995, pp. 767-775
1. The present study was carried out to investigate the effect of bila
teral adrenalectomy on fevers induced in rats by systemic injection of
interleukin-1 beta (IL-1 beta) or by central injection of prostagland
in E(2) (PGE(2)). 2. Intraperitoneal (I.P.) injections of two doses of
IL-1 beta (0.5 and 1.0 pg kg(-1)) induced biphasic fevers in normal c
ontrol rats in a dose-dependent manner. Adrenalectomized (ADX) rats sh
owed higher fevers than sham-ADX rats after I.P. injection of small do
ses of IL-1 beta (0.5 mu g kg(-1)). This fever enhancement was inhibit
ed by acute or chronic glucocorticoid, dexamethasone (DEX), treatment.
In contrast, there was no significant difference between fevers induc
ed in ADX and sham-ADX rats by I.P. injection of large doses of IL-1 b
eta (1.0 g kg(-1)). 3. Dose-dependent fevers were observed in normal c
ontrol rats after injections of several doses of PGE(2) (5, 25 and 100
ng) into the preoptic hypothalamic area (POA). The injection of a lar
ge dose of PGE(2) (100 ng) into the POA led to a lower fever in ADX ra
ts, compared with that in sham-ADX rats. This fever in ADX rats was in
creased by acute or chronic treatment with DEX. On the other hand, adr
enalectomy had no effect on fevers induced by the injections of small
doses of PGE(2) (5 and 25 ng) 4. The injections of PGE(2) (100 ng) int
o the POA induced increases in oxygen consumptions in ADX rats that we
re significantly smaller than those in sham-ADX rats, suggesting that
the lower PGE(2) fever was, at least in part, due to attenuated thermo
genesis in ADX rats. 5. There was no significant difference in plasma
osmolality between the ADX and the sham-ADX rats. The ADX rats were gi
ven 0.9% salt water instead of tap water. 6. These results suggest tha
t endogenous glucocorticoid is one of the important modulators of the
IL-1-induced and the PGE(2)-induced fevers in rats.