Trichobilharzia ocellata: influence of infection on the interaction between the dorsal body hormone, a female gonadotropic hormone, and the follicle cells in the gonad of the intermediate snail host Lymnaea stagnalis.
Activation of adenylate cyclase (AC)-cAMP system in follicle cells of Lymnaea stagnalis by the gonadotropic dorsal body hormone (DBH) is inhibited by schistosomin, an agent present in hemolymph of snails infected with Trichobilharzia ocellata. AC activation was determined enzyme cytochemically. This conclusion is based on the observation that the percentage of oocytes with AC-positive follicle cells in gonads incubated in the presence of schistosomin, i.e., in serum of infected snails (IS) with DBH, is significantly lower than that in gonads incubated in the absence of schistosomin, i.e., in serum of noninfected snails (NS) with DBH. Follicle cells in gonads preincubated in the absence of schistosomin, i.e., in NS, and subsequently incubated with freshly dissolved DBH showed a considerably lower response to DBH than those in not preincubated gonads. This indicates that the number of receptors for DBH on follicle cells had decreased during preincubation. The response to DBH also appeared to decrease when the hormone was preincubated in NS. This indicates that the activity of DBH decreases during preincubation. These data make it impossible to answer the question of whether or not schistosomin acts as an antagonist of DBH at the receptor level.
de Jong-Brink
M
M
Department of Biology, Vrije Universiteit, Amsterdam, The Netherlands.
Bergamin-Sassen
M J
MJ
D000262:Adenylyl Cyclases / Q000378:metabolism; D000818:Animals; D000242:Cyclic AMP / Q000378:metabolism; D005260:Female; D006062:Gonadotropins / Q000037:antagonists & inhibitors; D006066:Gonads / Q000166:cytology; D006458:Hemolymph; D036341:Intercellular Signaling Peptides and Proteins; D007447:Invertebrate Hormones / Q000037:antagonists & inhibitors / Q000502:physiology*; D008195:Lymnaea / Q000469:parasitology*; D009865:Oocytes / Q000166:cytology / Q000201:enzymology; D010455:Peptides / Q000502:physiology*; D011967:Receptors, Gonadotropin / Q000378:metabolism; D012551:Schistosomatidae
D006062:Gonadotropins; D036341:Intercellular Signaling Peptides and Proteins; D007447:Invertebrate Hormones; D010455:Peptides; D011967:Receptors, Gonadotropin; C054640:schistosomin; D000242:Cyclic AMP; D000262:Adenylyl Cyclases