Oestrogen-induced secretion of egg-yolk proteins by male xenopus in organ culture

THE BIOCHEMICAL SOCIETY 97P (50% inhibition obtained at 0.3mM). Glucose (2, 8 and 17mM) hadno effect on the activity ofthe enzyme, nor did galactose at the same concentrations. Groups of islets were incubated separately in two con- centrations of glucose (2 and 17mM) for periods of 5 or 15min. After incubation islets were harvested and homogenized, and the lOOOg pellet was assayed as before for adenylate cyclase activity. No differences between any groups of islets were observed. The following conclusions emerge: the adenylate cyclase of islets is similar in behaviour to other tissue adenylate cyclases. The preparation obtained retained its hormone-sensitive properties. Glucose had no effect on adenylate cyclase activity either in vivo or in vitro. Likewise galactose was without effect in vitro. It is concluded that glucose does not mediate insulin secretion via an effect on adenylate cyclase.