Abstract

(ilycogen synthesis after glucose nikTomjection m frog oocytes proceeds nuinh by an indirect pathway involving gluconeogenesis from triose compounds. Because <>f the known regulatory role of true tose-2,6-bisP on glucose uiili/ation we eoinjeeted (U- CJglucose und fructose-2,6-bisP into oocMev and observed a strong inhibition of label incorporation into ghcogeti, with an 1S value of 2 [.iM, similar to that for the in vitro inhibition of oocytc fructose-1,6-hisphosphatase. 2,5-anhydromannitol-l ,obisP Wns- (ts effective as IVuctose-2,6-hisP; glucose-1,6-bisP showed some eileci although the I,h Valuc was 2d nV1i fructose.-1,6-bisP had no effect at all i'he mtiacellular concentration of IVuctose2,6-bisP in unperturbed ooiNies uas found ID be between (1.1 and 0.2 (AM. 6-phosphofructo-2kinase ieVels in homogenates were between 0.02-0.06 mUnits per g of nv.iiv After 60 min incubation. fi'uciose-2.6-bisP microinjected into the one Me s ua_ almost completely degraded, suggesting that fructose-2,6bisphnsphalase is active in vivo. The results suggest an important role for mie!ose-2.(i-bisP in the in UVY> regulation of glucose utiliJ.ation in I roe oocytes.