2-Thioether-5'-O-(1-thiotriphosphate)-adenosine derivatives: new insulin secretagogues acting through P2Y-receptors.
P2-receptors (P2-Rs) represent significant targets for novel drug development. P2-Rs were identified also on pancreatic B cells and are involved in insulin secretion. The aim of our study was to synthesize and evaluate pharmacologically the novel P2Y-R ligands, 2-thioether-5'-O-phosphorothioate adenosine derivatives, as potential insulin secretagogues. An efficient synthesis of these nucleosides and a facile method for separation of the chiral products is described. The enzymatic stability of the compounds towards pig-pancreas NTPDase was evaluated. The rate of hydrolysis of 2-hexylthio-5'-O-(1-thiotriphosphate)-adenosine (2-hexylthio-ATP-alpha-S) isomers by NTPDase was 28% that of ATP. The apparent affinity of the compounds to P2Y1-R was determined by measurement of P2Y-receptor-promoted phospholipase C activity in turkey erythrocyte membranes. 2-RS-ATP-alpha-S derivatives were agonists, stimulating the production of inositol phosphates with K0.5 values in the nM range. 2-RS-AMP-S derivatives were full agonists although 2 orders of magnitude less potent. All the compounds were more potent than ATP. The effect on insulin secretion and pancreatic flow rate was evaluated on isolated and perfused rat pancreas. A high increase, up to 500%, in glucose-induced insulin secretion was due to addition of 2-hexylthio-ATP-alpha-S in the nM concentration range, which represents 100-fold enhancement of activity relative to ATP. 2-Hexylthio-AMP-S was 2.5 orders of magnitude less effective. A high chemical hydrolytic stability was observed for 2-hexylthio-ATP-alpha-S. Hydrolysis of the phosphoester bond, which was the only detectable degrading reaction under the investigation conditions (pH 7.4, 37 degrees C), was slow, with a half-life of 264 hours. Moreover, even at gastric juice conditions (pH 1.4, 37 degrees C), hydrolysis of the terminal phosphate was the only detectable reaction, with a half-life of 17.5 hours. 2-Hexylthio-ATP-alpha-S isomers are enzymatically and chemically stable. These isomers are highly potent and effective insulin secretagogues, increasing, however, pancreatic vascular resistance.
Fischer
B
B
Department of Chemistry, Gonda-Goldschmied Medical Research Center, Bar-Ilan University, Ramat Gan, Israel. bfischer@mail.biu.ac.il
Shahar
L
L
Chulkin
A
A
Boyer
J L
JL
Harden
K T
KT
Gendron
F P
FP
Beaudoin
A R
AR
Chapal
J
J
Hillaire-Buys
D
D
Petit
P
P
D017766:Acid Anhydride Hydrolases / Q000378:metabolism; D000227:Adenine Nucleotides / Q000378:metabolism / Q000494:pharmacology*; D000241:Adenosine / Q000031:analogs & derivatives* / Q000378:metabolism / Q000494:pharmacology*; D000818:Animals; D015195:Drug Design; D004912:Erythrocytes / Q000201:enzymology; D005947:Glucose / Q000494:pharmacology; D006207:Half-Life; D006863:Hydrogen-Ion Concentration; D006868:Hydrolysis; D007295:Inositol Phosphates / Q000096:biosynthesis; D007328:Insulin / Q000378:metabolism*; D000078790:Insulin Secretion; D007515:Islets of Langerhans / Q000187:drug effects; D007536:Isomerism; D008024:Ligands; D043583:Nucleoside-Triphosphatase; D010179:Pancreas / Q000098:blood supply / Q000201:enzymology; D051381:Rats; D018048:Receptors, Purinergic P2 / Q000187:drug effects*; D012636:Secretory Rate / Q000187:drug effects; D013440:Sulfides / Q000378:metabolism / Q000494:pharmacology*; D013552:Swine; D013873:Thionucleotides / Q000378:metabolism / Q000494:pharmacology*; D014422:Turkeys; D010738:Type C Phospholipases / Q000378:metabolism; D014655:Vascular Resistance / Q000187:drug effects
D000227:Adenine Nucleotides; D007295:Inositol Phosphates; D007328:Insulin; D008024:Ligands; D018048:Receptors, Purinergic P2; D013440:Sulfides; D013873:Thionucleotides; D010738:Type C Phospholipases; D017766:Acid Anhydride Hydrolases; D043583:Nucleoside-Triphosphatase; D005947:Glucose; D000241:Adenosine