Dual effect of ATP on glucose-induced insulin secretion in HIT-T15 cells.
OBJECTIVE
: The study investigated the dual effect of purinergic nucleotides on the secretion of insulin from pancreatic beta cells.


METHODS
: The level of insulin secretion in HIT-T15 cells of static incubation was measured using a radioimmunoassay.


RESULTS
: The adenine nucleotides reduced the level of glucose-induced insulin secretion in a concentration-dependent manner, and the relative potency order (IC50; muM) was BzATP (6.9) > ATP (20.4) >/= alpha, beta-methylene ATP (23.3) >/= 2-methylthio-ATP (24.9). Suramin and PPADS (200 muM), which are blockers of the purinergic receptors, had a little influence on the activity of ATP. However, the inhibitory effect of ATP was reversed by preincubation with oxidized ATP (200 muM), which is a P2X7 antagonist. The level of insulin secretion in these preincubated cells exposed to the purinergic nucleotides increased in the following order: ATP > alpha, beta-methylene ATP >/= 2-methylthio-ATP. A pretreatment with foskolin and PDBu (100 nM) potentiated the increasing effect of ATP on insulin secretion. The Western blotting showed the expression of P2X7 and P2Y11 receptors.


CONCLUSIONS
: Purinergic stimulation has inhibitory activity on glucose-dependent insulin secretion through the activation of the P2X7 receptor, whereas it has enhancing effect through the activation of the P2Y11 receptor in HIT-T15 cells.
Lee
Dong Hyeon
DH
Department of Physiology, College of Medicine, Pochon CHA University, Seongnam, Gyeonggi-Do, Republic of Korea.
Park
Kyu-Sang
KS
Kim
Dae-Ran
DR
Lee
Joong-Woo
JW
Kong
In Deok
ID
D000255:Adenosine Triphosphate / Q000031:analogs & derivatives / Q000378:metabolism* / Q000494:pharmacology; D000818:Animals; D002460:Cell Line; D005576:Colforsin / Q000494:pharmacology; D006224:Cricetinae; D000242:Cyclic AMP / Q000378:metabolism; D017868:Cyclic AMP-Dependent Protein Kinases / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D020536:Enzyme Activators / Q000494:pharmacology; D025461:Feedback, Physiological; D005947:Glucose / Q000378:metabolism*; D007328:Insulin / Q000378:metabolism*; D000078790:Insulin Secretion; D050417:Insulin-Secreting Cells / Q000187:drug effects / Q000378:metabolism*; D011493:Protein Kinase C / Q000378:metabolism; D011732:Pyridoxal Phosphate / Q000031:analogs & derivatives / Q000494:pharmacology; D018048:Receptors, Purinergic P2 / Q000187:drug effects / Q000378:metabolism; D058486:Receptors, Purinergic P2X7; D013498:Suramin / Q000494:pharmacology; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D013873:Thionucleotides / Q000494:pharmacology
D020536:Enzyme Activators; D007328:Insulin; C546468:P2RX7 protein, human; C109734:P2RY11 protein, human; D018048:Receptors, Purinergic P2; D058486:Receptors, Purinergic P2X7; D013873:Thionucleotides; C077792:pyridoxal phosphate-6-azophenyl-2',4'-disulfonic acid; D005576:Colforsin; C033901:3'-O-(4-benzoyl)benzoyladenosine 5'-triphosphate; D011732:Pyridoxal Phosphate; D013498:Suramin; D000255:Adenosine Triphosphate; D000242:Cyclic AMP; D017868:Cyclic AMP-Dependent Protein Kinases; D011493:Protein Kinase C; D005947:Glucose; D013755:Tetradecanoylphorbol Acetate; C002630:alpha,beta-methyleneadenosine 5'-triphosphate; C008501:2-methylthio-ATP