Mitogenic induction of ornithine decarboxylase in human mononuclear leukocytes: Relationships with adenosine diphosphate ribosyltransferase

Abstract

1. 1. Relationships between ornithine decarboxylase (ODC) and adenosine diphosphate ribosyl transferase (ADPRT) in human mononuclear leukocytes (HML) were tested by statistical comparisons of their values in a group of 46 people, and by use of inhibitors of ADPRT. 2. 2. ODC was assayed following exposure of HML, for 20 hr, to mitogens [phytohemagglutinin (PHA) and pokeweed mitogen]; ADPRT was measured following exposure of HML to H 2O 2, (100 μM) for 1 hr (activated ADPRT), and in parallel cultures without H 2O; (constitutive ADPRT). 3. 3. Significant correlations were found between ODC and ADPRT values; the effects of smoking disturbed the correlations. PHA induction of ODC was negatively influenced by age (standardized β coefficient = −2.95, P = 0.005), while age also influenced ADPRT values negatively in non-smokers (for H 2O 2, activated ADPRT, standardized β coefficient = −2.74, P < 0.008). 4. 4. Inhibitors of ADPRT, nicotinamide, caffeine and benzamide inhibited the induction of ODC by PHA in a concentration-dependent manner, in the range (0.6–10mM) known to inhibit ADPRT.