THE EFFECT OF IN-VITRO PROCEDURES ON CYCLIC-AMP ACCUMULATION IN HUMAN-LEUKOCYTES

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 4h (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.