Reduced in vivo biological activity of in vitro glycosylated insulin.
We evaluated the in vivo biological activity of in vitro extensively glycosylated insulin (GI) with the euglycemic-hyperinsulinemic glucose-clamp technique in postabsorptive nondiabetic subjects. Insulin-mediated glucose disposal was approximately 30% lower (P less than .03) with GI (9.2 +/- 1.2 mg.kg-1.min-1, mean +/- SE) than with the nonglycosylated hormone (12.6 +/- 0.7 mg.kg-1.min-1) at comparable plasma insulin concentrations (approximately 90 microU/ml). Binding of GI to a specific receptor on circulating cells (erythrocytes and monocytes) was normal. We conclude that in vitro extensive glycosylation of insulin reduces its biological activity in vivo, as reflected by insulin-mediated glucose disposal, probably at a postreceptor level.
Lapolla
A
A
Patologia Medica I., University of Padova, Italy.
Tessari
P
P
Poli
T
T
Valerio
A
A
Duner
E
E
Iori
E
E
Fedele
D
D
Crepaldi
G
G
D000328:Adult; D001667:Binding, Competitive; D002096:C-Peptide / Q000097:blood; D004912:Erythrocytes / Q000378:metabolism; D005947:Glucose / Q000378:metabolism; D006801:Humans; D007328:Insulin / Q000031:analogs & derivatives* / Q000097:blood / Q000502:physiology; D008297:Male; D009000:Monocytes / Q000378:metabolism
D002096:C-Peptide; D007328:Insulin; C039522:insulin, glycosylated; D005947:Glucose