Steroid utilization and fatty acid synthesis by the larva of the housefly Musca vicina Macq

Abstract

Housefly larvae are able to synthesize body fat from dietary protein; they require neither fatty acids nor carbohydrate in the medium. They also reproduce normally without any dietary source of fat during larval and adult life. Cholesterol (2 [mu]g/g of diet) stimulates growth of housefly larvae. Larval growth is proportional to the concentration of dietary cholesterol, up to a certain limit. Excess of cholesterol in the diet has no adverse effect. The influence of steroid structure on the utilizability was studied; some steroids are not only not utilized, but inhibit the utilization of other steroids. Cholesterol utilization by housefly larvae is reversibly inhibited by cholesteryl chloride. The utilization of steroids by insects is discussed in connection with their feeding habits.