Methylation of nicotinamide in rat liver cytosol and its correlation with hepatocellular proliferation

Eukaryotic nuclear ADP-ribosylation reactions

“…In addition it appears that much of this released nicotinamide is converted to 1-methylnicotinamide (Shaikh et al, 1980; reaction d) which has been shown to inhibit NAD synthesis from nicotinamide, and also to induce hepatocellular proliferation (Hoshino et al, 1982). (E*-ADPR) of the transferase (a-d) and subsequent automodification reactions (e-h).…”

Nutritional Factors Affecting the Activity of Liver Nicotinamide Methyltransferase and Urinary Excretion of TV1-Methylnicotinamide in Rats

“…13 mM, respectively. 4 ) In the present study, urinary excretion of MNA was elevated 182-fold by an excess of nicotinamide in the diet compared with that of the control (Table II). Accordingly, Johnson's suggestion is not correct, but, the level in the liver of the excess nicotinamide group had only a 1.7-fold elevation.…”

Characterization of Nicotinamide Methyltransferase in Livers of Mice Bearing Ehrlich Ascites Tumors: Preferential Increase of Activity

“…Nmd CHrtransferase activity was found to increase along with proliferation of the rat liv er after partial hepatectomy [13], Moreover, it was also found that l-CH^Nmd enhanced the growth of rat hepatocytes in cultured rat liver cells [25]. In contrast, Lea et al [26] failed to find any such effect on the growth of rat hepa toma cells.…”

“…Activity of Nmd CHjtransferase was assayed by a modified method of Hoshino et al [13]. The assay mixture of 50 pi consisted of 50 mil/ Tris-HCl buffer (pH 8.0), 2 mM dithiothreitol (DTT), 10 mM Nmd, 0.5 pCi 'H-SAM and enzyme preparation.…”

“…Liver sclices (100 mg wet weight) prepared [13] from the mouse 7 days after the transplantation of Ehr lich ascites tumor were incubated in 900 pi Hanks' bal anced solution (pH 7.4) with 0.5 pCi of 14C-Nmd for 30 min at 37 °C, and then homogenized in 200 pi of 5% trichloroacetic acid (TCA). An aliquot (100 pi) of the resulting supernatant was loaded onto Whatman 1 paper (20 x 20 cm) and developed by two-dimension al chromatography in the following solvent systems: 1-butanol saturated with 3% NH4OH (first dimen sion), and glacial acetic acid/1-butanol saturated with water (1/60; vol/vol) (second dimension) [15] in order to detect various metabolites of Nmd.…”