INFLUENCE OF THE ENDOCRINE SYSTEM ON TRYPTIC ACTIVITY IN FEMALE AEDES-AEGYPTI

In MNC-ablated or ovariectomized mosquitoes, blood-fed by enema, the tryptic activity of midgut homogenates was reduced by half. By sealing the anus after the blood meal, we showed that the reduction in enzyme activity was not due to premature or increased excretion of active enzyme in operated females. The enzyme activity was restored to the level of unoperated controls by either reimplantation of an ovary or injection of 20-hydroxy-ecdysone in a large, single dose shortly before the blood meal. The reduction in tryptic activity in MNC-ablated or ovariectomized females did not alter the rate of protein digestion as measured by the decrease of protein in midgut homogenates. We conclude that the neurosecretory system and the ovaries are required for maximal tryptic activity in normal females, and that the enzyme apparently is secreted in excess of that required for complete digestion of the blood meal. © 1979.