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 methodo logical procedures or protocols on cyclic AMP formation in human leuco cytes. The data showed that: (1) ATP content and lactate production wa s 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 pe riods (years), whereas day-to-day variation within a week was less imp ortant; (4) whole blood could be stored for up to 4h (at 4-degrees-C o r 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 phospho diesterase inhibitors markedly influenced the basal and isoprenaline-i nduced cAMP accumulation. Evidence is provided that the rate of cAMP a ccumulation in response to isoprenaline of cells incubated in the pres ence of 2.5 mM 3-isobutyl-1-methyl-xanthine (IBMX) is reflecting the r ate of cellular cAMP production.