CAMP-induced influx

Fig. 5 Proposed signal transduction mechanisms that stimulate the pheromone biosynthetic pathway in Helicoverpa zea and Bombyx mori. It is proposed that PBAN binds to a G protein-coupled receptor present in the cell membrane that upon PBAN binding will induce a receptor-activated calcium channel to open causing an influx of extracellular calcium. This calcium binds to calmodulin and in the case of B. mori will directly stimulate a phosphatase that will dephosphorylate and activate a reductase in the biosynthetic pathway. In H. zea the calcium-calmodulin will activate adenylate cyclase to produce cAMP that will then act through kinases and/or phosphatases to stimulate acetyl-CoA carboxylase in the biosynthetic pathway...

The Di receptor is typically associated with the stimulation of adenylyl cyclase (Table 9-1) for example, Di-receptor-induced smooth muscle relaxation is presumably due to cAMP accumulation in the smooth muscle of those vascular beds in which dopamine is a vasodilator. D2 receptors have been found to inhibit adenylyl cyclase activity, open potassium channels, and decrease calcium influx. 

Soroker and Rafaeli, 1995). This confirmed that calcium is involved in pheromone biosynthesis and that there is a cross-talk between the two messengers, since the increase in calcium, as a result of the ionophores, induced the increase in cAMP. This reinforces the hypothesis that cAMP stimulation occurs downstream of the calcium influx (Jurenka et al., 1991c Soroker and Rafaeli, 1995). 

Liberation of fatty acids induced by phospholipases is connected with a decrease in the pH. We speculate therefore that this change in pH together with the change in cell wall organization induced by lysolecithins may cause the influx of Ca " ions into the cell, where Ca " -ions together with cAMP activate phosphorylation. 

Its primary action is inhibiting the release of GH from the pituitary gland. Somatostatin al.so suppresses the release of both insulin and glucagon. It causes a decrease in both cAMP levels and adenylate cyclase activity. It also inhibits calcium ion influx into the pituitary cells and suppresses glucose-induced pancreatic insulin secretion by activating and deactivating potassium ion and calcium ion permeability, respcc-tively. The chemistry. SARs, and potential clinical applications have been reviewed.--- ... 

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