The pyrogenic properties of some C-19 and C-21 steroids were examined by in vitro incubation of human blood leukocytes with serum-buffer solutions of the steroids and injection of the 18-hr supernatants into rabbits. In previous studies this method demonstrated release of leukocyte endogenous pyrogen by etiocholanolone. With two exceptions, steroids known to cause fever in man, such as 11β-OH etiocholanolone and 3α-hydroxy-5β-pregnane-20-one were also pyrogenic in vitro. All steroids tested which are nonpyrogenic in man, such as androsterone, 3β-OH etiocholanolone, and 3α, 17α-dihydroxy-5β-pregnan-20-one were also nonpyrogenic in vitro. Solubility in aqueous solution did not correlate with pyrogenic capacity.
G. M. Dillard, Phyllis Bodel