A comparison of the inhibitory effects of somatostatin-14, -25, and -28 on motility of the guinea pig ileum.
A number of studies have suggested that somatostatin-14 (SS-14) and somatostatin-28 (SS-28) exhibit a similar spectrum of biological activities but have different potencies. In the present study the effects of SS-14, SS-28, and somatostatin-25 on electrically induced contractions of the guinea pig ileum have been compared. All three peptides exhibited equipotent inhibitory effects. Inhibition was obtained at a threshold concentration less than 10(-10) M, with maximal inhibition at 10(-7) M and IC50 values of 6.0-6.5 X 10(-10) M. The N-terminal 14 amino acid fragment of SS-28 had no effect either on motility, when added alone, or on the actions of SS-28, suggesting that this region of the molecule is not critical for biological activity.
McIntosh
C H
CH
Bakich
V
V
Kwok
Y N
YN
Brown
J C
JC
D000109:Acetylcholine / Q000494:pharmacology; D000818:Animals; D004558:Electric Stimulation; D005260:Female; D006168:Guinea Pigs; D007082:Ileum / Q000187:drug effects; D066298:In Vitro Techniques; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects; D009130:Muscle, Smooth / Q000187:drug effects*; D013004:Somatostatin / Q000494:pharmacology*; D053561:Somatostatin-28
D013004:Somatostatin; C026568:somatostatin 25; D053561:Somatostatin-28; D000109:Acetylcholine