Figure 5.

Effect of pertussis toxin on PGE₂-mediated inhibition of glucagon-dependent cyclic AMP synthesis. In each experiment, OMCD samples were microdissected from the same rat kidney, preincubated (2 h at 30°C) and incubated (4 min at 35°C) in 1 mM Ca²⁺ medium without (control) or with 500 ng ml⁻¹ PTX. Data are the mean values calculated from four experiments peformed in the presence of 1 mM IBMX. ^*Refers to the effect of 0.3 μM PGE₂ on the cyclic AMP synthesis induced by 1 μM glucagon, P<0.001 in each experiment; NS indicates that the effect of PGE₂ was not significantly different from the response to glucagon.