The lipids of the common house cricket,Acheta domesticus L. III. Sterols

Abstract

Sterols constitute 1.95% of the total extractable lipids ofAcheta domesticus L., of which 18% are esterified. The free sterols consist of cholestane-3beta-ol (0.5%), Delta(5)-cholestene-3beta-ol (83.5%), Delta(7)-cholestene-3beta-ol (2.3%) Delta(5,7)-cholestadiene-3beta-ol (3%), Delta(5,22)-cholestadiene-3beta-ol (4%), Delta(5,7,22)-cholestatriene-3beta-ol (0.2%), campestane-3beta-ol (0.03%), Delta(5)-campestene-3beta-ol (1.0%), Delta(7)-campestene-3beta-ol (trace), Delta(5,7)-campestadiene-3beta-ol (0.2%), stigmastane-3beta-ol (0.09%), Delta(5)-stigmastene-3beta-ol (2.1%), Delta(7)-stigmastene-3beta-ol (0.04%), Delta(5,7)-stigmastadiene-3beta-ol (0.4%), Delta(5,22)-stigmastadiene-3betaol (0.1%). The same sterols are present in the esterified sterol fraction. Delta(7)-Sterols and Delta(5,7)-sterols are present in significantly larger amounts in the esterified fraction than in the free sterol fraction. By a comparison with the sterols of the cricket food, it is clear thatA. domesticus is capable of removing methyl and ethyl groups from C-24 of sterols of the campestane and stigmastane type. The ability to introduce a Delta(7) double bond into saturated and Delta(5)-sterols is indicated, and it is suggested that Delta(7)-sterols of the C(27), C(28), and C(29) sterol series may be intermediates in the conversion of Delta(5)-sterols to Delta(5,7)-sterols.