Metabolic actions of insulin-like growth factor I in cultured glomerular mesangial cells.
Glomerular mesangial cells in culture have been reported to possess a considerable number of receptors specific to insulin-like growth factor I (IGF-I), with very small number of receptors specific to insulin. To explore acute metabolic effects of IGF-I on mesangial cells, uptake of glucose and amino acid was measured in the presence of IGF-I or insulin. IGF-I stimulated D-[U-14C]glucose incorporation, 2-deoxy[1-3H]glucose uptake and alpha-[methyl-3H]aminoisobutyric acid (AIB) uptake into cultured mesangial cells by 139.8% +/- 2.1%, 116.6% +/- 1.7%, and 214.9% +/- 12.8% (percent of basal), respectively. Similar maximal stimulation was also induced by insulin, while the ED50 of IGF-I to stimulate these uptake systems (9.98 +/- 2.36, 3.45 +/- 1.86, and 3.35 +/- 0.40 ng/mL, respectively) was significantly lower than that of insulin (120.8 +/- 28.5, 61.8 +/- 7.7, and 76.3 +/- 17.5, respectively). These results indicate that, in cultured glomerular mesangial cells, IGF-I induces acute metabolic effects, possibly through its own receptors.
Haneda
M
M
Third Department of Medicine, Shiga University of Medical Science, Japan.
Kikkawa
R
R
Togawa
M
M
Koya
D
D
Kajiwara
N
N
Shigeta
Y
Y
D000596:Amino Acids / Q000493:pharmacokinetics; D000621:Aminoisobutyric Acids / Q000493:pharmacokinetics; D000818:Animals; D002478:Cells, Cultured; D003847:Deoxyglucose / Q000493:pharmacokinetics; D005920:Glomerular Mesangium / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D007328:Insulin / Q000378:metabolism / Q000494:pharmacology; D007334:Insulin-Like Growth Factor I / Q000378:metabolism / Q000494:pharmacology*; D013936:Thymidine / Q000493:pharmacokinetics
D000596:Amino Acids; D000621:Aminoisobutyric Acids; D007328:Insulin; C100049:2-aminoisobutyric acid; D007334:Insulin-Like Growth Factor I; D003847:Deoxyglucose; D013936:Thymidine