Meeting Abstract

P2.32A  Monday, Jan. 5  A comparative study of MIH signaling in the brachyuran molting gland WILLIAMS, S.A.*; COVI, J.A.; MCDONALD, A.A.; CHANG, S.A.; CHANG, E.S.; MYKLES, D.L.; Colorado State Univ., Fort Collins; UC Davis Bodega Marine Lab, Bodega Bay sere@gpspowell.info

Molt inhibiting hormone (MIH) regulates the production of ecdysteroids by the crustacean molting gland (Y-organ or YO). Ecdysteroids are hormones that regulate the physiological process of molting. Upon binding to a membrane receptor in the YO, MIH induces a second messenger cascade involving cyclic nucleotides (cAMP and cGMP), which inhibit ecdysteroidogenesis. Previous studies have used pharmacological agonists in an attempt to mimic the effects of MIH on YO ecdysteroid secretion in vitro. Adenylyl cyclase activators, cAMP and cGMP analogs, and NO-donors inhibit ecdysteroidogenesis in the YO. Moreover, YOs express NO synthase (NOS) and GC-I. These data suggest that NOS and GC-I are components of the MIH signaling pathway. The purpose of this study was to determine if antagonists of the putative signaling components block MIH action in YOs in vitro. This analysis involves two species of brachyuran crab, Gecarcinus lateralis and Carcinus maenas. The effects of adenylyl cyclase, NOS, or GC-I antagonists on MIH-dependent YO inhibition will be reported. Supported by NSF (IBN-0342982 and IOS-0745224).