ATPase activity of rat hepatocytes membrane under the influence of nicotinic acid adenine dinucleotide phosphate

M.Vergun, S.Bychkova

Ivan Franko National University of Lviv
4, Hrushevskyi St., Lviv 79005, Ukraine

This paper studied the effect of nicotinic acid adenine dinucleotide phosphate (NAADP) on rat hepatocytes membranes ATPase active. We found a statistically significant reduction of specific Na+, K+-ATPase activity of microsomal fraction by (59,538,85)%, (p=0,05, n=7) at presence of NAADP. Also, it was found that NAADP reduces basal Mg2+-ATPase activity of rat hepatocytes membranes by (66,688,42)%, (p=0,001, n=9). However, it is shown that the specific Ca2+ -ATPase activity of microsomal fraction under the actions of NAADP increases by (71,656,43)% (p=0,017 n=8). It is speculated that NAADP-released calcium is actively transported by Ca2+-pumps as the endoplasmic reticulum and also by pumps of the plasma membrane and that require close localization of NAADP receptors and Ca2+-ATPase in membranes of rat hepatocytes.

Keywords: NAADP, ATPase activity, hepatocytes, microsomal fraction

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