Cloning of rat KATP-2 channel and decreased expression in pancreatic islets of male Zucker diabetic fatty rats.
ATP-regulated potassium channels play a key role in regulating insulin secretion. We have isolated cDNA clones from a RINm5F insulinoma cell cDNA library that encode a protein, KATP-2, whose sequence shows 72% identity with the rat heart potassium channel KATP. RNA blotting showed that KATP-2 mRNA was present at high levels in brain and undetectable in heart, spleen, lung, liver, skeletal muscle, kidney and testis. A quantitative RT-PCR assay indicated that there were 1.85 +/- 0.32 x 10(5) molecules of KATP-2 mRNA per microgram of total RNA in pancreatic islets from nondiabetic rats. The levels of KATP-2 mRNA were reduced by 34% in islets from diabetic Zucker diabetic fatty male rats, a model of non-insulin dependent diabetes mellitus, compared to their lean nondiabetic littermates (p < 0.05), suggesting that decreased expression of KATP-2 may contribute to beta-cell dysfunction in this animal model.
Stoffel
M
M
Howard Hughes Medical Institute, University of Chicago, Illinois 60637, USA.
Tokuyama
Y
Y
Trabb
J B
JB
German
M S
MS
Tsaar
M L
ML
Jan
L Y
LY
Polonsky
K S
KS
Bell
G I
GI
D000255:Adenosine Triphosphate / Q000378:metabolism*; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D003001:Cloning, Molecular; D017931:DNA Primers / Q000235:genetics; D003921:Diabetes Mellitus, Experimental / Q000235:genetics / Q000378:metabolism; D007515:Islets of Langerhans / Q000378:metabolism*; D008297:Male; D008969:Molecular Sequence Data; D009765:Obesity / Q000235:genetics / Q000378:metabolism; D016133:Polymerase Chain Reaction; D015221:Potassium Channels / Q000235:genetics* / Q000378:metabolism*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D051381:Rats; D011924:Rats, Zucker; D017386:Sequence Homology, Amino Acid; D014018:Tissue Distribution
D017931:DNA Primers; D015221:Potassium Channels; D012333:RNA, Messenger; D000255:Adenosine Triphosphate