Acute inhibition of proinsulin biosynthesis at the translational level by palmitic acid.
The effects of fatty acids on pancreatic beta cell are still controversial. Here, in order to determine whether free fatty acids acutely affect beta cell functions, we studied the effect of palmitic acid (PA) on proinsulin biosynthesis and insulin secretion using rat islets in vitro. Exposure of islets to PA for 1 h reduced glucose-stimulated proinsulin biosynthesis in a dose-dependent manner; in contrast, no change in insulin secretion was observed after 1 h incubation with PA. Furthermore, PA treatment did not cause any change of preproinsulin mRNA level during 1-h incubation period. Thus, our data indicate that PA primarily suppresses glucose-induced proinsulin biosynthesis within 1 h at the translational level.
Katahira
H
H
Third Department of Internal Medicine, Kyorin University School of Medicine, Tokyo, Japan.
Nagamatsu
S
S
Ozawa
S
S
Nakamichi
Y
Y
Yamaguchi
S
S
Furukawa
H
H
Takizawa
M
M
Yoshimoto
K
K
Itagaki
E
E
Ishida
H
H
D000818:Animals; D005947:Glucose / Q000494:pharmacology; D066298:In Vitro Techniques; D007328:Insulin; D007515:Islets of Langerhans / Q000187:drug effects* / Q000378:metabolism*; D008297:Male; D019308:Palmitic Acid / Q000494:pharmacology*; D011384:Proinsulin / Q000096:biosynthesis* / Q000235:genetics* / Q000378:metabolism; D014176:Protein Biosynthesis / Q000187:drug effects; D011498:Protein Precursors / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar
D007328:Insulin; D011498:Protein Precursors; D012333:RNA, Messenger; D019308:Palmitic Acid; C013737:preproinsulin; D011384:Proinsulin; D005947:Glucose