Fundamental studies have determined that midgut of insect is the major site of cholesterol absorption and conversion. After transport by vascular lipoprotein in hemolymph, cholesterol is consumed by the prothoracic glands. 中肠是吸收转化胆固醇的主要部位,然后通过血.淋巴中的脂蛋白,运送到前胸腺转化利用;