Genital tract growth factors from a moth, the tobacco budworm, Heliothis virescens

Development and maturation of the genital tract of the moth, Heliothis virescens, takes place within a few days in the pupal stage. The insect steroid hormone, 20-hydroxyecdysone (20E), essential during this period, stimulated testis sheath and fat body tissue to secrete factors that, in turn, stimulated growth and development of pupal spermducts and genital imaginal discs in vitro. Factors could be extracted in aqueous solution from tissues incubated for 24 h in media containing 1000pg/microliters 20E, and partially purified by chromatography on polyacrylamide gels. Ten active molecular weight fractions were separated from testis sheath extracts, and 9 from fat body extracts. Most fractions were labile to protease, although the activity of six of the fractions was also destroyed by lipase. Testis sheath, fat body tissue, and active fractions, caused partial development of the genital tract in vitro, as well as increased incorporation of [3H]methionine into precipitable protein and [3H]thymidine into nuclear material.