Effects of two gonadotropic hormones on polysaccharide synthesis in the albumen gland of Lymnaea stagnalis, studied with the organ culture technique.

A medium for culturing organs of the basommatophoran freshwater snail Lymnaea stagnalis is described. One of the accessory sex glands, the albumen gland, which produces proteins and galactogen as nutritive substances for the embryos, was cultured along with parts of the central nervous system (CNS), including the female gonadotropic hormone-producing dorsal bodies (DB). Culture time was 4 days. The cerebral ganglia and the DB appeared to have a strong stimulating influence on polysaccharide synthesis in the albumen gland. The remaining part of the CNS has a weak stimulating effect. The use of extracts (culture time 6-26 hr) of parts of the cerebral ganglia and of the DB showed that not only the dorsal body hormone (DBH), but also the ovulation hormone (CDCH)--a neurohormone produced by the caudodorsal cells located in the cerebral ganglia--stimulates the synthetic activity of the albumen gland. The action of these hormones is direct; i.e., it is not exerted via the gonad. Dose- and time-response relations for the DBH and the CDCH are very similar. No additional rise in stimulation occurred when the two hormones were administered together. Experiments with albumen glands of adult snails demonstrated that the presence of large quantities of secretory material in the gland inhibits the response to DBH and CDCH.