title: Somatostatin-like immunoreactivity in mammalian thyroid glands: contents and partial characterization.
abstract: Somatostatin (SRIF)-like immunoreactivity (SLI) in the thyroid glands of human and several animal species were compared, and the SLI peptides were characterized chromatographically and immunologically. All specimens were extracted with 2 M acetic acid, and the SLI content determined by RIA. The SLI concentrations in guinea pigs [34.3 +/- (SE) 4.8 ng/mg protein] and rabbits (9.4 +/- 0.8 ng/mg protein) were much greater than those in other mammals: dogs, rats, mice, and humans. On gel filtration of extracts of the guinea pig, rabbit and dog thyroids, the major peak of SLI (1.6 K SLI) coeluted with synthetic SRIF-14 (S-14). Two other forms of SLI ("big" SLI and 3 K SLI) were also detected, although their relative proportions to total SLI were small (2.3 to 8.2%). The 3 K SLI and 1.6 K SLI from guinea pig and rabbit thyroids contained peptides coeluting with synthetic SRIF-28 (S-28) and S-14, respectively, on reverse-phase high performance liquid chromatography. The dilution curves of the two molecular forms of SLI, i.e. 3 K SLI and 1.6 K SLI, were parallel to the displacement curves of S-28 and S-14 in the SRIF RIA. It is concluded 1) that the thyroid contents of SLI varied greatly from species to species, with the highest content being found in guinea pig thyroids; 2) that in guinea pigs, rabbits, and dogs, the predominant form of thyroid SLI is 1.6 K SLI; and 3) that the 3 K SLI and 1.6 K SLI peptides from guinea pig and rabbit thyroids are immunologically and chromatographically indistinguishable from S-28 and S-14, respectively.
mesh_terms: D000818:Animals; D002850:Chromatography, Gel; D002851:Chromatography, High Pressure Liquid; D004285:Dogs; D005260:Female; D006168:Guinea Pigs; D008297:Male; D051379:Mice; D008809:Mice, Inbred C3H; D011817:Rabbits; D011863:Radioimmunoassay / Q000379:methods; D051381:Rats; D011919:Rats, Inbred Strains; D013004:Somatostatin / Q000032:analysis*; D013045:Species Specificity; D013961:Thyroid Gland / Q000032:analysis*
chemical_list: D013004:Somatostatin