Fig. 2. Regulation of oocyte maturation in vitro. Oocytes were cultured in vitro in the presence of reagents to examine the mechanisms of maturation (A). Reagents that increase the level of cAMP in a cell inhibit germinal vesicle breakdown (GVBD) (100 µg/ml dibutyrl cAMP, 125 µm IBMX; 100 µg/ml theophylline). Cells noted in recovery were treated for 12 hours with IBMX (125 µm) and dcAMP (100 µg/ml), and then washed into ASW so that in the 24 and 36 hour time points, 12 hours of this time was in the inhibitor. (B) Roscovitine at 0.1, 0.5, 2 µM; olomoucine at 10, 30 and 90 µM; LiCl, at 30 µM; and CF, coelomic fluid at 50%. Asterisk indicates significantly different from control values at P>0.01 confidence level determined by Student’s t-test analysis. (C) Control oocytes matured into eggs containing pronuclei (arrow), within 24 hours of incubation. (D) Sibling oocytes cultured for 24 hours in the presence of 100 µg/ml dibutyrl cAMP; note the distinct and centrally located germinal vesicle, arrow. (E) Sibling oocytes cultured for 24 hours in the presence of 0.1 µM roscovitine, note distinct but mis-shapened germinal vesicle, arrow. Scale bar: 50 µM.

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