TY - JOUR
T1 - Comparison of the gastric exocrine inhibitory activities and plasma kinetics of somatostatin-28 and somatostatin-14 in cats
AU - Hirst, Barry H.
AU - Conlon, J. Michael
AU - Coy, David H.
AU - Holland, Joy
AU - Shaw, Bernard
N1 - Funding Information:
We thank Mr. K. Elliott and Mr. D. Stephenson for expert technical assistance and Dr. J.R. Greenwell for assistance with computing. This work was supported in part by grants from the National Institute of Health (AM 18370), the Wellcome Trust and the British Diabetic Association. The British Council, Physiological Society, Wellcome Trust and Royal Society are thanked for travel grants to B.H.H. J.H. is a Science and Engineering Research Council C.A.S.E. scholar.
PY - 1982/9
Y1 - 1982/9
N2 - The gastric exocrine inhibitory activities of somatostatin-28 (SS-28) and somatostatin-14 (SS-14) were determined in conscious cats prepared with gastric fistulae. Gastric acid and pepsin secretions were stimulated with pentagastrin. Expressed in terms of exogenous doses, SS-14 (ID50: 1.49 nmol · kg-1 · h-1) was 3.4 times more potent than SS-28 (ID50: 5.12 nmol · kg-1 · h-1) as an inhibitor of gastric acid secretion. Similarly SS-14 (ID50: 0.25 nmol · kg-1 · h-1) was 3.8 times more potent than SS-28 (ID50: 0.96 nmol · kg-1 · h-1) as an inhibitor of pepsin secretion. Expressed in terms of circulating plasma concentration measured by radioimmunoassay, SS-14 (ID50: H+, 232 and pepsin 73 pM) was 8-9 times more potent than SS-28 (ID50: H+, 2112 and pepsin, 611 pM) as an inhibitor of gastric exocrine secretions. The plasma immunoreactive half-life of SS-28 (6.1 min) was double that for SS-14 (2.4 min) possibly due to a slower theoretical metabolic clearance rate of the larger peptide (30 and 87 ml · kg-1 · min-1, respectively). Both peptides had similar apparent distribution volumes (SS-14, 306 and SS-28, 263 ml · kg-1). As judged by gel chromatography of plasma samples, there was no evidence for the conversion of SS-28 to SS-14 in vivo. The reduced activity of SS-28, compared with SS-14, against gastric exocrine secretions contrasts with its more potent effects in the pituitary and pancreas.
AB - The gastric exocrine inhibitory activities of somatostatin-28 (SS-28) and somatostatin-14 (SS-14) were determined in conscious cats prepared with gastric fistulae. Gastric acid and pepsin secretions were stimulated with pentagastrin. Expressed in terms of exogenous doses, SS-14 (ID50: 1.49 nmol · kg-1 · h-1) was 3.4 times more potent than SS-28 (ID50: 5.12 nmol · kg-1 · h-1) as an inhibitor of gastric acid secretion. Similarly SS-14 (ID50: 0.25 nmol · kg-1 · h-1) was 3.8 times more potent than SS-28 (ID50: 0.96 nmol · kg-1 · h-1) as an inhibitor of pepsin secretion. Expressed in terms of circulating plasma concentration measured by radioimmunoassay, SS-14 (ID50: H+, 232 and pepsin 73 pM) was 8-9 times more potent than SS-28 (ID50: H+, 2112 and pepsin, 611 pM) as an inhibitor of gastric exocrine secretions. The plasma immunoreactive half-life of SS-28 (6.1 min) was double that for SS-14 (2.4 min) possibly due to a slower theoretical metabolic clearance rate of the larger peptide (30 and 87 ml · kg-1 · min-1, respectively). Both peptides had similar apparent distribution volumes (SS-14, 306 and SS-28, 263 ml · kg-1). As judged by gel chromatography of plasma samples, there was no evidence for the conversion of SS-28 to SS-14 in vivo. The reduced activity of SS-28, compared with SS-14, against gastric exocrine secretions contrasts with its more potent effects in the pituitary and pancreas.
KW - gastric acid secretion
KW - pentagastrin
KW - pepsin secretion
KW - prosomatostatin
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U2 - 10.1016/0167-0115(82)90115-X
DO - 10.1016/0167-0115(82)90115-X
M3 - Article
C2 - 6128770
AN - SCOPUS:0020438802
SN - 0167-0115
VL - 4
SP - 227
EP - 237
JO - Regulatory Peptides
JF - Regulatory Peptides
IS - 4
ER -