Prostaglandins of the E and F series in rabbit plasma were estimated by radioimmunoassay after chromatographic separation during fever following the intravenous injection of Newcastle disease virus, E. coli-endotoxin, or endogenous pyrogen. Although concentrations of prostaglandins from both series are increased considerably by the three pyrogens, there seemed to be no correlation between prostaglandin concentrations in plasma and body temperature. These findings were supported by the fact,

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... after the injection of tritiated prostaglandin E1 into the carotid arteries of normal or feverish animals no radioactivity was detectable in cerebrospinal fluid. The enhanced prostaglandin concentrations in plasma night be responsible for various pathological effects observed during fever such as diarrhoea and abortion.