Progesterone production and oocyte maturation of frog (Rana nigromaculata and Rana rugosa) follicles in vitro
1990
Kwon, H.B. (Chonnam National Univ., Kwangju (Korea Republic). Coll. of Natural Sciences) | Kim, J.Y. (Chonnam National Univ., Kwangju (Korea Republic). Dept. of Nuclear Medicine) | Ko, S.K. (Honam Coll., Kwangju (Korea Republic). Dept. of Biology)
Progesterone production and oocyte maturation in ovarian follicles of Rana nigromaculata and Rana rugosa were investigated. Addition of frog pituitary homogenate (FPH) to the in vitro cultured follicles of R. nigromaculata stimulated a marked increase in the accumulation and secretion of progesterone (P4 by the follicles and induced their oocyte maturation (germinal vesicle breakdown, GVBD) in a dose dependent manner. The FPH (0.1 pituitary equivalent/2ml)- inducted P4 peak appeared in 3-6 hours and followed by the oocyte GVBD in 9-12 hours after the hormone stimulation. Increase of intrafollicular cAMP levels with forskolin (an adenylate cyclase stimulator) and 3-isobutyl-1-methylxanthine (IBMX, a phosphodiesterase inhibitor) mimic the FPH action in the stimulation of P4 production but not in the induction of oocyte maturation. The in vitro cultured follicles of R. rugosa behaved very differently from other amphibian follicles. Addition of FPH-(0.1 pit. equiv/2 ml) to the culture medium neither stimulated P4 production by the follicles nor induced the oocyte GVBD. However, treatment of the follicles with forskolin and IBMX drastically stimulated both the intrafollicular accumulation (800 pg/follicle) and secretion (1700 pg/follicle) of P4 by the follicles during culture period. Thus, the data suggest that the follicles are ready to respond to cAMP increase but not to the FPH stimulation in terms of P4 production
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