A large molecular form of glucagon-like peptide-1 (GLP-1) immunoreactivity is co-released with glucagon from pancreas by arginine in normal subjects.
Plasma immunoreactivities of glucagon-like peptide-1 (GLP-1IR) in normal subjects were measured with a specific radioimmunoassay during the arginine tolerance test. Plasma GLP-1IR after arginine infusion showed a 3-fold increase in parallel to plasma glucagon immunoreactivity and plasma glucagon-like immunoreactivity, measured with a glucagon C-terminal specific antiserum (OAL 123) and an N-terminal and/or central region specific glucagon antiserum (OAL 196), respectively. This finding suggested that the increased immunoreactivities of GLP-1 as well as that of glucagon were of pancreatic origin. Upon gel chromatography, plasma at the basal state showed three GLP-1 immunoreactive peaks, eluted in the position of void volume, synthetic GLP-1(72-108), and a smaller molecular fraction. Gel chromatography of plasma after an arginine load showed an additional peak (Mr 13,000-15,000) with little change in other GLP-1 immunoreactive peaks. This large molecular form of GLP-1IR was also shown to exist in the human pancreatic extract. Moreover, the free GLP-1 concentrations in plasma before and after an arginine load were shown to be about equal by reverse phase HPLC. These data suggested that in normal subjects arginine stimulation co-releases GLP-1IR, predominantly large molecular form, with glucogen from the pancreas.
Hirota
M
M
Shimizu
I
I
Ohboshi
C
C
Nishino
T
T
Shima
K
K
D000328:Adult; D001120:Arginine / Q000494:pharmacology*; D001786:Blood Glucose / Q000032:analysis; D002850:Chromatography, Gel; D002851:Chromatography, High Pressure Liquid; D005934:Glucagon / Q000378:metabolism*; D052216:Glucagon-Like Peptide 1; D006801:Humans; D007275:Injections, Intravenous; D007328:Insulin / Q000032:analysis; D010179:Pancreas / Q000378:metabolism*; D010455:Peptides / Q000378:metabolism*
D001786:Blood Glucose; D007328:Insulin; D010455:Peptides; D052216:Glucagon-Like Peptide 1; D005934:Glucagon; D001120:Arginine