20-Hydroxyecdysone, Juvenile Hormone and Biogenic Amines: Mechanisms of Interaction in Control of Drosophila Reproduction Under Normal and Stressful Conditions

Abstract

Juvenile hormone (JH) and ecdysteroids play a gonadotropic role in insect reproduction. For the normal progress of oogenesis, a proper balance between JH and 20-hydroxyecdysone (20E) is of a paramount importance. An imbalance of gonado- tropins (shifting the balance either to the side of JH or 20E) leads to reproductive defects: a rise in JH titre leads to oviposition arrest, a rise in 20E level, to the degrada- tion of vitellogenic oocytes. Upon a change in the level of one of the gonado tropins as a result of a mutation, effect of a stressor or pharmacological agent, the balance is restored owing to the relative change in the titre of the other one. Mediators in the JH and 20E interrelationship are biogenic amines, dopamine and octopamine. Existence of the mechanism of gonadotropin's - reciprocal regulation is adaptive.