Effects of exogenous ecdysteroid titer on endogenous ecdysteroid production in vitro by testes of the tobacco budworm, Heliothis virescens
Loeb, MJ.; Brandt, EP.; Woods, CW.
Journal of Experimental Zoology 2401: 75-82
1986
ISSN/ISBN: 0022-104X
DOI: 10.1002/jez.1402400110
Accession: 001580713
Testes or the isolated sheaths of testes from last-instar larvae of the noctuid Heliothis virescens spontaneously secreted ecdysteroids in vitro. Exogenous 20-hydroxyecdysone, incubated with the testes or isolated testis sheaths, functioned in a local positive feedback system to increase production of the several ecdysteroids typical of H. virescens testes. The increase in ecdysteroid production by testis tissue was dependent on discrete ranges in exogenous ecdysteroid titre.