ARS | Publication request: POTENTIAL ROLES OF INTRAOVARIAN GROWTH FACTORS DURING FOLLICLE MATURATION IN RAINBOW TROUT (ONCORHYNCHUS MYKISS)

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: March 8, 2006
Publication Date: June 16, 2006
Citation: Lankford, S.E., Weber, G.M. 2006. Potential roles of intraovarian growth factors during follicle maturation in rainbow trout (Oncorhynchus mykiss). Meeting Abstract.

Technical Abstract: For years the regulation of follicle maturation in fishes has focused on the roles of pituitary derived peptides (i.e., luteinizing hormone and follicle stimulating hormone) and sex steroids, while the roles of intraovarian growth factors have been largely ignored. Critical roles for intraovarian growth factors have been identified in mammals, but little is known about these regulators in fishes. We investigated the ovarian mRNA expression of members of the transforming growth factor beta (TGF-beta) superfamily and some of their known inhibitors [i.e., bone morphogenetic protein 4 and 7 (BMP4 & 7), growth and differentiation factor 9 (GDF9), inhibin, follistatin, and BAMBI (BMP and activin membrane-bound inhibitor)], as well as insulin-like growth factor I & II (IGF-I & II), during follicle maturation in rainbow trout. The responses to incubation with maturation inducing hormone (MIH; 17 alpha,20 beta-dihydroxy-4-pregnen-3-one), IGF-I, estradiol (E2), testosterone, and human chorionic gonadotropin were investigated. Incubation with MIH caused a ~21-fold increase in BAMBI mRNA, while all other transcripts remained unchanged. The stimulatory effect of MIH on BAMBI mRNA was also examined for dose dependence and steroid specificity. Both of these characteristics were confirmed, supporting a role for BAMBI in the regulation of follicle maturation in fishes.