TY - JOUR
T1 - Determination of endogenous levels of cyclic ADP-ribose in rat tissues
AU - Walseth, Timothy F.
AU - Aarhus, Robert
AU - Zeleznikar, Robert J.
AU - Lee, Hon Cheung
PY - 1991/8/13
Y1 - 1991/8/13
N2 - Cyclic ADP-ribose (cADPR) is a potent mediator of calcium mobilization in sea urchin eggs. The cADPR synthesizing enzyme is present not only in the eggs but also in various mammalian tissue extracts. The purpose of this study was to ascertain whether cADPR is a naturally occurring nucleotide in mammalian tissues. Rat tissues were frozen and powdered in liquid N2, followed by extraction with perchloric acid at -10°C. [32P]cADPR was prepared and used as a tracer. The acid extracts were chromatographed on a Mono-Q column and cADPR in the fractions were determined by its ability to release Ca2+ from egg homogenates. That the release was mediated by cADPR and not inositol triphosphate (IP3) in the extracts was shown by the fact that the homogenates, subsequent to Ca2+ release induced by active fractions, were desensitized to authentic cADPR but not to IP3. Furthermore, the Ca2+ release activity was shown to co-elute with [32P]cADPR. The endogenous level of cADPR determined in rat liver is 3.37 ± 0.64 pmol/mg, in heart is 1.04 ± 0.08 pmol/mg and in brain is 2.75 ± 0.35 pmol/mg. These results indicate cADPR is a naturally occurring nucleotide and suggest that it may be a general second messenger for mobilizing intracellular Ca2+.
AB - Cyclic ADP-ribose (cADPR) is a potent mediator of calcium mobilization in sea urchin eggs. The cADPR synthesizing enzyme is present not only in the eggs but also in various mammalian tissue extracts. The purpose of this study was to ascertain whether cADPR is a naturally occurring nucleotide in mammalian tissues. Rat tissues were frozen and powdered in liquid N2, followed by extraction with perchloric acid at -10°C. [32P]cADPR was prepared and used as a tracer. The acid extracts were chromatographed on a Mono-Q column and cADPR in the fractions were determined by its ability to release Ca2+ from egg homogenates. That the release was mediated by cADPR and not inositol triphosphate (IP3) in the extracts was shown by the fact that the homogenates, subsequent to Ca2+ release induced by active fractions, were desensitized to authentic cADPR but not to IP3. Furthermore, the Ca2+ release activity was shown to co-elute with [32P]cADPR. The endogenous level of cADPR determined in rat liver is 3.37 ± 0.64 pmol/mg, in heart is 1.04 ± 0.08 pmol/mg and in brain is 2.75 ± 0.35 pmol/mg. These results indicate cADPR is a naturally occurring nucleotide and suggest that it may be a general second messenger for mobilizing intracellular Ca2+.
KW - Ca mobilization
KW - Cyclic ADP-ribose
KW - Second messenger
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U2 - 10.1016/0167-4889(91)90032-S
DO - 10.1016/0167-4889(91)90032-S
M3 - Article
C2 - 1883849
AN - SCOPUS:0025831860
VL - 1094
SP - 113
EP - 120
JO - Biochimica et Biophysica Acta - Molecular Cell Research
JF - Biochimica et Biophysica Acta - Molecular Cell Research
SN - 0167-4889
IS - 1
ER -