Genistein augments cyclic adenosine 3'5'-monophosphate(cAMP) accumulation and insulin release in MIN6 cells.
Effects of genistein on insulin release were studied using MIN6 cells, a glucose-sensitive insulinoma cell line. At the non-stimulatory concentrations of glucose, genistein did not affect insulin release, however, at the stimulatory concentrations of glucose, genistein significantly increased insulin release in a dose-dependent manner up to 20 micrograms/ml. The content of cAMP in MIN6 cells was also elevated significantly by genistein and the dose-response relationship between the genistein and cAMP accumulation was consistent with the relationship between the genistein and insulin release. These effects were inhibited by calcium antagonists or by the omission of extracellular calcium. Isobutylmethylxanthine (IBMX;0.1mM) increased both cAMP accumulation and insulin release in MIN6 cells and there were no additive effects by the addition of genistein. The accumulation of cAMP might have, at least in part, resulted from phosphodiesterase inhibition by genistein. These results suggest that genistein augments glucose-induced insulin release by the contribution of cAMP accumulation and calcium modulation which depends on extracellular calcium.
Ohno
T
T
2nd Department of Internal Medicine, Gunma University School of Medicine, Japan.
Kato
N
N
Ishii
C
C
Shimizu
M
M
Ito
Y
Y
Tomono
S
S
Kawazu
S
S
D015056:1-Methyl-3-isobutylxanthine / Q000494:pharmacology; D000818:Animals; D002118:Calcium / Q000494:pharmacology; D002460:Cell Line / Q000187:drug effects; D000242:Cyclic AMP / Q000032:analysis / Q000378:metabolism*; D003600:Cytosol / Q000737:chemistry / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D019833:Genistein; D005947:Glucose / Q000494:pharmacology; D007328:Insulin / Q000378:metabolism*; D007340:Insulinoma / Q000737:chemistry / Q000378:metabolism* / Q000473:pathology*; D007515:Islets of Langerhans; D007529:Isoflavones / Q000494:pharmacology*; D051379:Mice; D009543:Nifedipine / Q000494:pharmacology; D010190:Pancreatic Neoplasms / Q000737:chemistry / Q000378:metabolism* / Q000473:pathology*; D011505:Protein-Tyrosine Kinases / Q000037:antagonists & inhibitors; D014407:Tumor Cells, Cultured
D007328:Insulin; D007529:Isoflavones; D019833:Genistein; D000242:Cyclic AMP; D011505:Protein-Tyrosine Kinases; D009543:Nifedipine; D005947:Glucose; D002118:Calcium; D015056:1-Methyl-3-isobutylxanthine