150-kD oxygen-regulated protein is an essential factor for insulin release.
OBJECTIVE
This study was designed to show the induction and function of 150-kD oxygen-regulated protein (ORP150) in insulin secretion in vitro.


METHODS
A mouse beta-cell line, MIN6 cells, was cultured in medium containing potassium channel openers or various concentrations of glucose (2-25 mmol/L). ORP150 expression was studied by reporter assay, Western blot, or Northern blot analysis, concomitantly with insulin secretion. In addition, MIN6 cells infected with ORP150 recombinant adenovirus were adopted to show the function of ORP150 in insulin release.


RESULTS
ORP150 expression in MIN6 cells was suppressed dose-dependently by the potassium channel opener diazoxide. Both low glucose (<2 mmol/L) and high glucose concentrations (25 mmol/L glucose) significantly induced more ORP150 expression compared with 10 mmol/L glucose. The treatment with diazoxide or infection of ORP150 antisense adenovirus suppressed ORP150 expression, and glucose-stimulated insulin secretion was effectively prevented.


CONCLUSIONS
These findings show the involvement of ORP150 in insulin secretion in MIN6 cells.
Kobayashi
Tomohiro
T
HSP Research Institute, Kyoto Research Park, Kyoto, Japan.
Ohta
Yasuhiko
Y
D000256:Adenoviridae / Q000235:genetics; D000818:Animals; D016375:Antisense Elements (Genetics); D045744:Cell Line, Tumor; D019806:Cromakalim / Q000494:pharmacology; D003981:Diazoxide / Q000494:pharmacology; D017930:Genes, Reporter; D005947:Glucose / Q000494:pharmacology; D018840:HSP70 Heat-Shock Proteins; D007328:Insulin / Q000378:metabolism*; D000078790:Insulin Secretion; D050417:Insulin-Secreting Cells / Q000166:cytology / Q000378:metabolism*; D007340:Insulinoma; D051379:Mice; D020110:Pinacidil / Q000494:pharmacology; D015221:Potassium Channels / Q000502:physiology; D011506:Proteins / Q000235:genetics* / Q000378:metabolism*; D014665:Vasodilator Agents / Q000494:pharmacology
D016375:Antisense Elements (Genetics); D018840:HSP70 Heat-Shock Proteins; D007328:Insulin; D015221:Potassium Channels; D011506:Proteins; D014665:Vasodilator Agents; C050087:oxygen-regulated proteins; D019806:Cromakalim; D020110:Pinacidil; D005947:Glucose; D003981:Diazoxide