Stimulation of in vitro ovarian estradiol-17 beta synthesis in the rainbow trout by the carbohydrate-poor protein fraction from sockeye salmon pituitary glands.
The role of carbohydrate-poor (Con A I) and carbohydrate-rich (Con A II) pituitary protein fractions, isolated from sockeye salmon (Oncorhynchus nerka), were investigated pertaining to in vitro estradiol-17 beta (E2) production by rainbow trout (Oncorhynchus mykiss) ovarian follicles. During the early vitellogenic phase of the reproductive cycle, using defolliculated ovarian follicle preparations (outer epithelium-thecal layer absent), it was demonstrated that the Con A I fraction was capable of increasing E2 production, in the presence of exogenous testosterone (T) as the substrate. Under similar conditions the Con A II fraction (containing the maturational gonadotropin) was inactive. However the Con A II fraction or T, separately, increased E2 production by intact ovarian follicles, whereas the Con A I fraction did not. A mechanism proposed to explain the regulation of ovarian E2 synthesis involves the Con A I fraction enhancing aromatase activity in granulosa cells permitting an increased conversion of T to E2.
Nagler
J J
JJ
Ocean Sciences Centre, Memorial University of Newfoundland, St John's, Canada.
Idler
D R
DR
D000818:Animals; D002241:Carbohydrates / Q000032:analysis; D004958:Estradiol / Q000378:metabolism*; D005260:Female; D066298:In Vitro Techniques; D007700:Kinetics; D006080:Ovarian Follicle / Q000187:drug effects / Q000378:metabolism*; D010053:Ovary / Q000187:drug effects / Q000378:metabolism*; D010902:Pituitary Gland / Q000502:physiology*; D012474:Salmon; D013739:Testosterone / Q000378:metabolism; D014020:Tissue Extracts / Q000494:pharmacology; D014337:Trout
D002241:Carbohydrates; D014020:Tissue Extracts; D013739:Testosterone; D004958:Estradiol