9603710 Gilbert These studies concentrate on the means by which a hormone from the insect brain acts upon specialized glands (prothoracic glands) to cause these glands to synthesize a specific steroid hormone, an ecdysteroid. Ecdysteroids cause the insect to molt i.e. shed its exoskeleton, so that it can grow. These hormones also elicit metamorphosis i.e. the phenomenon by which a caterpillar is transformed into a pupa and then into an adult moth or butterfly. The brain neurohormone that is synthesized and released as a result of environmental cues and the synthesis and release of ecdysteroids by the prothoracic glands must be extremely precise if the insect is to survive and be successful. This grant will allow the PI to study the means by which this peptide hormone interacts with the prothoracic glands via a cascade of events that includes compounds known as second messengers i.e. cyclic AMP and protein kinases. The role of these second messengers is the focus of this grant application and the mechanisms the PI has thus far examined are very similar to that of the human adrenal cortex which is stimulated by a pituitary hormone that also elicits the synthesis of steroids i.e. corticosteroids. By utilizing the insect prothoracic glands which are composed of a single layer of homogenous cells, the PI hopes to gain insights into the mechanism of general peptide hormone induced steroidogenesis that would not be possible with the more heterogenous adrenal gland. Further, any differences found between the two systems could be exploited by those studying the control of insect pests which so adversely affect human health and nutrition.
