Primary hepatocytes were isolated from 12-week-old male Prom1+/+ (WT) or Prom1-/- (KO) mice, serum-starved and stimulated with glucagon. I. Relative PKA activities 10 minutes after glucagon stimulation (10 nM) were determined using the PKA assay kit in the absence or presence of 10 μM IBMX (n = 3 mice/group). 