The effect of in vitro procedures on cyclic AMP accumulation in human leucocytes

The aim of this study was to investigate the effect of various methodological procedures or protocols on cyclic AMP formation in human leucocytes. The data showed that: (1) ATP content and lactate production was unaffected by hypotonic lysis during leucocyte isolation; (2) there was a linear relation between cell number/sample and the production of cyclic adenosine 3':5'-monophosphate (cAMP); (3) the interindividual variation markedly affected cAMP production during long observation periods (years), whereas day-to-day variation within a week was less important; (4) whole blood could be stored for up to 4 h (at 4 degrees C or 23 degrees C) without affecting cAMP accumulation; (5) isolated MNL could be stored for up to 2 h (at 4 degrees C) without affecting cAMP accumulation; and finally that (6) choice and concentration of phosphodiesterase inhibitors markedly influenced the basal and isoprenaline-induced cAMP accumulation. Evidence is provided that the rate of cAMP accumulation in response to isoprenaline of cells incubated in the presence of 2.5 mM 3-isobutyl-1-methyl-xanthine (IBMX) is reflecting the rate of cellular cAMP production.