Enzymatic-synthesis and degradation of nicotinate adenine dinucleotide phosphate (NAADP), a Ca²⁺-releasing agonist, in rat tissues

We have recently found that nicotinate adenine dinucleotide phosphate (NAADP) is a potent agonist that triggers Ca²⁺ release from intracellular stores of sea urchin eggs, and that its action is distinct from effects of IP₃ and cyclic ADP-ribose (J. Biol. Chem. 270:3216, 1995). Now we report: that extracts from rat brain, heart, liver, and spleen but not kidney cortex contain enzymatic activity which catalyzes NAADP synthesis by exchange of nicotinamide for nicotinic acid and which is probably catalyzed by NAD(P)-glycohydrolase. Extracts from these tissues also inactivate NAADP in the rank inverse to their ability for NAADP synthesis. These results suggest that NAADP, a Ca²⁺ -releasing agent, can be generated in mammalian tissues, namely in brain.