Relative in vitro effectiveness of various steroid hormones on oocyte maturation in catfish Heteropneustes fossilis

Abstract

The relative in vitro effectiveness of various steroids ( Cj,, Cj^, C^^ on general
vesicle breakdown (GVBD) using folliculated oocytes of Indian catfish
Heteropneustes fossilis and carp Catla catla were investigated. 17a-hydroxy-20
PP dihydroprogesterone (I7a-20PP) was found to be the most effective maturation
inducing steroid (MIS) in both catfish and carp. Among Cj^ and Cjg group of
steroids, androsterone were fairly effective, however estradiol - 17|3 and testosterone
were totally ineffective in inducing oocyte maturation. Deoxy-corticosterone,
hydrocortisone, progesterone and 17a-hydroxy progesterone (17aP) were
also effective, whereas the role is more pronounced at the higher hormone concentrations.
Among the 5P- reduced pregnans except 5P-pregnane-3L-ol-20 one, all
pregnanes derivative used were effective for inducing oocyte maturation, however,
relatively higher effectiveness was observed in SP- pregnane - 3,17a diol-20
- one. The significance of these findings is discussed in relation to the progestagen
as natural MIS in catfish and carps, and the earlier controversial position of MIS
in H. fossilis is discussed in light of available literature and made more clear by
establishing 17a - 20 pP as the maturation inducing steroid in fishes.