In vivo effect of ACE inhibiting in mealworms on ovarian composition and ecdysteroid amounts

Captopril is an inhibitor of angiotensin converting enzyme (ACE) used against arterial hypertension in mammals. The aim of this study was to evaluate captopril in the mealworm Tenebio molitor (Coleoptera: Tenebrionidae). The drug was diluted in acetone and administered topically (10 microg/3microl) on newly emerged adult females. The biochemical composition (proteins, lipids, carbohydrates, nucleic acids) and the ecdysteroid amounts of ovaries were determined at day 4 following treatment corresponding to the end of the vitellogenesis process. Biochemical analyses revealed that captopril applied in vivo reduced both total protein, lipid and carbohydrate amounts of ovaries, respectively. In addition, measurement of ecdysteroids by an enzyme-immunoassay indicated a significant decrease in ovarian ecdysteroid amounts. As a consequence, the reduction of reproductive capacity is possibly related to ecdysteroid production. Further experiments are needed to determine the action mechanism of captopril and the functions of ACE in insects.