The response of the follicle cells of Rhodnius prolixus to juvenile hormone and antigonadotropin in vitro

In a medium consisting of 40% Eagle's basal medium in Schneider's Drosophila medium, large spaces appear between the cells of the follicular epithelium over vitellogenic oocytes of Rhodnius prolixus when juvenile hormone is present. Such spaces are less prominent when juvenile hormone is absent. A method is described by which the size and number of spaces can be assigned a value, on a scale of 0–5, called the index of patency. The index of patency increases with increasing concentration of juvenile hormone from 10−15 μl/ml to 10−4 μl/ml. At higher concentrations, the index of patency decreases. When a source of antigonadotropin is present in the medium, together with juvenile hormone at its maximally effective concentration, the patency index is decreased.