The insect oocyte sequesters nutritive proteins during patency, which is facilitated as a result of intercellular spaces occurring between follicular epithelial cells under the influence of juvenile hormone (JH). Patency was analyzed in the moth, Heliothis virescens, using a pharmacological approach, in which we used different JH homologues and chemicals that specifically target elements of two second-messenger pathways in vertebrates, the cAMP-dependent and inositol triphosphate/diacylglycerol signaling pathways. Our results suggest that both JH I and JH III evoke dose-dependent patency in H. virescens oocyte follicles via activation of Na/K-ATPase. However, JH I stimulates patency via a signaling pathway that uses protein kinase A and cAMP, and is barely dependent on extracellular calcium sources, whereas JH III evokes patency via the inositol triphosphate/diacylglycerol signaling pathway that involves protein kinase C, mobilization of intracellular calcium sources and, additionally, utilizes extracellular calcium. The role of calcium/calmodulin- dependent kinase in signaling from JH I and JH III is discussed.