Endocrine Regulation of Fat Body Development and Function

On superficial observation the insect fat body appears to function mainly as a storage site for lipids; however, in reality it is the principal tissue for intermediary metabo­ lism. Kilby (72) likens the fat body to the vertebrate liver since both tissues store excess nutrients, detoxify foreign chemicals, and serve as the biosynthetic sources for circulating metabolites. This review undertakes to examine and evaluate some of the literature concerning the hormonal regulation of fat body development and metabolism. Insect hormones are usually viewed from the aspect of their morphogenic effects. However, it is increasingly apparent that like other highly integrated and complex animals, insects also have a variety of hormones that influence intermediary metabolism. As the central tissue for intermediary metabolism, the fat body is the focus of attention for these endocrine controls. This review cannot always present the completed picture of a given relationship because many research efforts are still in progress; neverthe­ less, a partial report on the state of the art may stimulate new efforts to expand the research record. Relationships between hormones and fat body metabolism have been discussed in other reviews of special topics. For further comments the interested reader is referred to the following reviews that deal, in part, with special aspects of fat body metabolism: Kilby (71, 72); Steele (Il l , 112); Price (93); Goldsworthy & Mordue (51); Engelmann (36); and Wyatt (133).