The concerted action of hormones such as juvenile hormone and allatotropin is necessary for egg development in Heliothis virescens. The action of these hormones is mediated by various second messengers. Results from research in our laboratory and data from some recently published studies provide evidence that the H. virescens allatotropin may be structurally similar or even identical to that of Manduca sexta (Mas-AT). We have demonstrated that Mas-AT-immunoreactive material is present in the H. virescens central nervous system, and also in axons projecting into the neuroendocrine corpora allata (CA). Allatotropns presumably act on the CA by binding to membrane receptors of CA cells, thereby stimulating intracellular signal transduction pathways. We have demonstrated that Mas-AT may stimulate CA activity by increasing intracellular Ca2+ concentration. The corpora allata of H. virescens is rather insensitive to changes in extraglandular Ca2+ concentrations, suggesting efficient regulation of Ca2+ homeostasis in CA cells. Data from experiments in which we investigated the effects on CA activity of varying Ca2+ concentrations and of the Ca2+ ionophore A23187 in one-day-old virgin H. virescens females, indicated that an increase in intracellular Ca2+ may be correlated with stimulation of JH biosynthesis. Current studies are addressing the potential involvement of the inositoltrisphosphate/diacylglycerol signaling pathway, the cyclic AMP signaling pathway, the cyclic GMP signaling pathway, of Ca2+/CaM dependent protein kinases and of protein phosphatases. This talk will discuss the mediation of allatotropin activity in the reproductive physiology of moths.
Species 1: Lepidoptera Noctuidae Heliothis virescens (Tobacco budworm)
Species 2: Lepidoptera Sphingidae Manduca sexta (Tobacco hornworm)
Keywords: corpora allata, Ca2+
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