TY - JOUR
T1 - Properties of endogenous somatostatin like immunoreactivity and synthetic somatostatin in dog plasma
AU - Conlon, J. M.
AU - Srikant, C. B.
AU - Ipp, E.
AU - Schusdziarra, V.
AU - Vale, W.
AU - Unger, R. H.
PY - 1978
Y1 - 1978
N2 - Somatostatin-like immunoreactivity (SLI) in the peripheral venous plasma of dogs and in their pancreatic and gastric venous effluents was characterized and compared with synthetic somatostatin. Both endogenous plasma SLI and somatostatin added to plasma were eluted from Sephadex gels at pH 8.8 in the 150,000-200,000-mol. wt region but at pH 2.5 both appeared in the 1,500-2,000-mol. wt region. The SLI released from the isolated dog pancreas perfused with plasma-free buffer was eluted entirely as a 1,600-dalton polypeptide, but when the pancreas was perfused with plasma, SLI was eluted in the 150,000-200,000-mol. wt zone. Affinity chromatography of plasma samples on immobilized antibodies directed against the central portion of the somatostatin molecule (residues 5-9 and 11) removed congruent to 90% of both endogenous SLI and somatostatin added to plasma, but neither was removed by affinity chromatography on antibodies directed against the NH2-terminal region of somatostatin (residues 1-4). The SLI from plasma and from pancreas perfusate isolated by affinity chromatography was identical in molecular size, charge, and immunometric properties to synthetic somatostatin. It is concluded that endogenous SLI is secreted by the pancreas and stomach in a form not distinguishable from synthetic somatostatin, but circulates in plasma bound to large molecular weight components; the NH2-terminal residues of somatostatin appear to be important in this binding.
AB - Somatostatin-like immunoreactivity (SLI) in the peripheral venous plasma of dogs and in their pancreatic and gastric venous effluents was characterized and compared with synthetic somatostatin. Both endogenous plasma SLI and somatostatin added to plasma were eluted from Sephadex gels at pH 8.8 in the 150,000-200,000-mol. wt region but at pH 2.5 both appeared in the 1,500-2,000-mol. wt region. The SLI released from the isolated dog pancreas perfused with plasma-free buffer was eluted entirely as a 1,600-dalton polypeptide, but when the pancreas was perfused with plasma, SLI was eluted in the 150,000-200,000-mol. wt zone. Affinity chromatography of plasma samples on immobilized antibodies directed against the central portion of the somatostatin molecule (residues 5-9 and 11) removed congruent to 90% of both endogenous SLI and somatostatin added to plasma, but neither was removed by affinity chromatography on antibodies directed against the NH2-terminal region of somatostatin (residues 1-4). The SLI from plasma and from pancreas perfusate isolated by affinity chromatography was identical in molecular size, charge, and immunometric properties to synthetic somatostatin. It is concluded that endogenous SLI is secreted by the pancreas and stomach in a form not distinguishable from synthetic somatostatin, but circulates in plasma bound to large molecular weight components; the NH2-terminal residues of somatostatin appear to be important in this binding.
UR - http://www.scopus.com/inward/record.url?scp=0018074467&partnerID=8YFLogxK
U2 - 10.1172/JCI109238
DO - 10.1172/JCI109238
M3 - Article
AN - SCOPUS:0018074467
SN - 0021-9738
VL - 62
SP - 1187
EP - 1193
JO - Journal of Clinical Investigation
JF - Journal of Clinical Investigation
IS - 6
ER -