Effectors of the cAMP pathways increase the recovery of βAPP maturation products in SwβAPP751-expressing HEK293 cells. Stably transfected HEK293 cells overexpressing SwβAPP751 were preincubated for 1 hr with or without actinomycin D (5 µg/ml) then incubated and metabolically labeled in the same conditions, in the absence (control) or presence of the indicated cAMP agonists. Secreted Aβ40 (A), Aβ42 (B) and APPα (D) were immunoprecipitated as described in Figure 2. Intracellular total Aβs (C) was immunoprecipitated with FCA18 as described in Materials and Methods. Densitometric analysis of gels radioautographies of secreted Aβ40 and Aβ42 (E) and APPα (F) are expressed as the percent of control densitometry obtained in the absence of effector with or without actinomycin D. Bars are the means of four to five independent experiments.