Cholesterol and cholesterol ester in haemolymph of the American cockroach, Periplaneta americana L.

Abstract

The plasma component of haemolymph from adult Periplaneta americana contains cholesterol and cholesterol esters. The percentage of cholesterol that is nonesterifled remains at 80–82% in male and female insects and in cockroaches that have been starved for 3 days. Label from [1-¹⁴C] palmitic acid is incorporated into the cholesterol ester fraction of plasma within 4 h of feeding or injecting the substrate, and incorporation of label from fed [carboxy- ¹⁴C]trioleylglycerol into this fraction has also been demonstrated. Relatively little label from injected [1-¹⁴C]palmitic acid is incorporated into cholesterol esters of the haemocyte fraction of whole haemolymph.