Functional binding of a vertebrate hormone, L-3,5,3 '-triiodothyronine (T-3), on insect follicle cell membranes

A vertebrate hormone, L-3,5,3'-triiodothyronine (T-3), induces volume reduc tion in the follicle cells of Locusta migratoria and Rhodnius prolixus. The effect of T-3 on locust follicle cells is inhibited by ouabain and by anti bodies raised against a membrane binding protein for juvenile hormone (JH). [I-125]-T-3 binds to membrane preparations of vitellogenic follicles in a specific and saturable fashion, with a K-D in the low nanomolar range. T-3 and JH III exhibited equivalent abilities to compete for the T-3 binding si te. These findings strongly suggest that T-3 and JH act via the same recept or in follicle cells. (C) 1999 Elsevier Science Ltd. All rights reserved.