Evidence for the involvement of adenosine 3',5'-cyclic monophosphate in fever genesis

In rabbit cerebrospinal fluid (CSF) during fever induced by endotoxins, myxoviruses, or endogenous pyrogen, concentrations of adenosine 3',5'-cyclic monophosphate (cyclic AMP) and prostaglandin E (PGE) are about 2-fold higher in comparison to normal values. In endotoxin treated animals paracetamol reduced the fever reaction and both PGE and cyclic AMP levels. Administration of theophyllin together with endotoxin enhanced the fever reaction and cyclic AMP levels in CSF, but had no influence on stimulation of PGE synthesis. Following injection of PGE2 into the lateral cerebral ventricles increased cyclic AMP concentrations were found in CSF. The results suggest, that the pyrogenic effect of PGE is mediated by stimulation of cerebral cyclic AMP synthesis.

Inhibition of Newcastle disease virus-induced fever in rabbits by cycloheximide

Pretreatment with cycloheximide prevents virus-induced fever in rabbits. Compared to the febrile control animals, CH-pretreated afebrile animals exhibit similar concentrations of endogenous pyrogen in the blood and of prostaglandins of the E-group and adenosine 3', 5'-cycle monophosphate in the cerebrospinal fluid. The fever response seems to involve one or several additional so far unknown mediators which are sensitive to cycloheximide.

Pyrogenic principle of the ribonucleic acid from the yeast Candida utilis

Experiments were performed to characterize the pyrogenic principle of ribonucleic acid (RNA) from the yeast Candida utilis. It was shown that ribonuclease hydrolysis of the RNA does not lead to inactivation of the pyrogenicity. Pyrogenicity was, however, destroyed by treatment with sodium deoxycholate. On column chromatography with Biogel under sterile and pyrogen-free conditions, the pyrogenic principle of yeast RNA was eluted together with the RNA. After treatment of the RNA with ribonuclease, it was possible to separate the pyrogenic activity from the RNA (hydrolysis products) to a great extent. Column chromatography of Escherichia coli endotoxin showed that the endotoxin was eluted in the same fractions as the pyrogenic activity of yeast RNA. On the basis of the behavior of the pyrogen, it may very well be that the fever reaction is produced not by the nucleic acid but by pyrogenic contaminants of the RNA preparation.