Inducible protective processes in animal systems: VIII. Enhancement of adaptive response by nicotinamide

The molecular mechanism of the adaptive response or upon activation catalyses of poly(ADP-ribosyl)ation of the inducible DNA repair process has not been clearly various nuclear proteins and also that of PARP by utilizing demonstrated in eukaryotic systems. The involvement of NAD as substrate. Furthermore, the adaptive response was poly(ADP-ribose) polymerase (PARP), a DNA repair prevented in vitro, when inhibitors of PARP were administered enzyme has been reported in the adaptive response (Shadley 2 h after the adaptive treatment (Wiencke et al., 1986; Shadely and Wolff, 1987; Wiencke, 1987). Hence, the present studies and Wolff, 1987; Wiencke, 1987). These reports suggest the were undertaken to understand the role of PARP in ethyl involvement of PARP in the adaptive response. Hence, in the methanesulfonate (EMS)-induced adaptive response in present investigations, an attempt has been made using in vivo mouse bone marrow cells by employing the inhibitor of mouse bone marrow cells to understand the role of the PARP this enzyme, nicotinamide. Inter-, pre- and post-treatments in ethyl methanesulfonate (EMS)-induced adaptive response. of nicotinamide with EMS were made. The results have Nicotinamide, as an inhibitor of PARP (Purnell and Whish, revealed that there is a reduction in the frequencies of 1980), has enhanced the EMS-induced adaptive response. The chromosomal aberrations compared with combined or involvement of PARP in the adaptive response and the above challenge treatment at the different recovery times tested. results are discussed in this paper. These results are discussed with reference to the enhancement of the adaptive response by nicotinamide in mouse Materials and methods bone marrow cells.