HORMONAL-CONTROL OF THE FOLLICULAR EPITHELIUM DURING VITELLOGENIN UPTAKE

Among the many functions of follicle cells in the insect ovary is the regulation of the entrance into the follicle of the vitellogenin circu lating in the hemolymph. The vitellogenin enters the follicle via larg e spaces which appear between the follicle cells. The appearance of th ese spaces (patency) is a result of a reduction in volume of the folli cle cells caused by the action of juvenile hormone which activates a j uvenile-hormone-sensitive Na+K+ ATPase via a pathway involving protein kinase C. A putative juvenile hormone receptor protein has been ident ified in membranes from follicle cells. An antigonadotropin, a small n europeptide, antagonizes the action of juvenile hormone on the follicl e cells.