Juvenile hormone induction of esterases: a mechanism for the regulation of juvenile hormone titer.

Within a few hours after injection of juvenile hormone into Hyalophora gloveri pupae, several fast-migrating carboxylesterases (EC 3.1.1.1) that are sensitive to diisopropylfluorophosphate appear in the hemolymph. Treatment of the pupae with puromycin or actinomycin D prevents the appearance of these hemolymph enzymes, suggesting de novo synthesis of the carboxylesterases. Of the several other compounds investigated, only a potent mimic of the juvenile hormone is able to induce these enzymes. When the induced enzymes are incubated in vitro with (14)C-labeled juvenile hormone, the hormone is rapidly and efficiently degraded. It is suggested that these induced carboxylesterases play an important role in the regulation of juvenile hormone titer.