THE ACTION OF JUVENILE-HORMONE AND ANTIGONADOTROPIN ON THE FOLLICLE CELLS OF LOCUSTA-MIGRATORIA

The follicular epithelium surrounding the vitellogenic oocytes of Locusta migratoria develops large spaces between the cells (becomes ''patent'') when the ovary is exposed in vitro to JH III or methoprene. In the presence of JH III, the optical path difference (OPD) of individual follicle cells in vitro, as measured by quantitative interference microscopy, increases markedly (i.e., the volume of the cell decreases). This response is inhibited by ouabain, indicating the involvement of Na+/K+ ATPase in the response. Methoprene also increases the OPD. JH II is less effective, while JH I and the bis-epoxide of JH III are without effect. Extracts of the abdominal neurosecretory organs of Rhodnius prolixus, a known source of an antigonadotropin which antagonizes the action of JH I on the follicle cells of Rhodnius, also antagonize the action of JH III on the follicle cells of locusts. Antigonadotropic activity was found in crude extracts of the thoracic ganglia of Locusta but was absent from other parts of the nervous system. These observations extend the range of species in which JH controls yolk uptake by affecting the follicle cells, and suggests that antigonadotropins may be widely spread in insects.