Showing papers by "Rosalyn S. Yalow published in 1982"

Post-translational processing of cholecystokinin in pig brain and gut

Abstract: A sequential extraction method employing methanol extraction of the COOH-terminal fragments of cholecystokinin (CCK) from pig tissues followed by HCl extraction of intact CCK and its NH2-terminal fragments is described. Radioimmunoassay of extracts and their fractionation by Sephadex chromatography and HPLC demonstrate that the distributions of COOH-terminal and NH2-terminal immunoreactivities among various regions of brain are similar and independent of the concentrations in individual regions. The distribution in gut differs from that in brain. Greatest concentrations of CCK immunoreactivity are located in cortical tissue in the brain and in duodenal mucosa in gut. Both brain and gut contain CCK octapeptide (CCK8) and an NH2-terminal fragment that is likely to be desoctapeptide-CCK33. Intact CCK33 is extractable from gut but not from brain. Brain contains another NH2-terminal immunoreactive molecule lacking COOH-terminal immunoreactivity that may be a peptide with a COOH-terminal extension, as has been described for gastrin, or one that may not be derived from a CCK33-like precursor. This peptide is much less prominent in gut, or may be nonexistent there. The failure to find CCK33 in the brain and the presence in the brain of this as-yet-uncharacterized NH2-terminal peptide raises the question as to whether the differences between neuronal and mucosal tissues are a consequence of differences in post-translational processing or in the DNA templates.

Absence of pork-like insulin in guinea pig tissues

Abstract: By using a technique for concentrating insulin 100-fold from tissue extracts with 75-95% recoveries, we earlier failed to detect pork-like insulin in guinea pig tissues and thus were unable to confirm reports from the National Institutes of Health that these tissues contain a pork-like insulin at concentrations averaging 1 ng/g. This difference could have been due to differences in strains of guinea pigs studied or in the species specificities of the antisera used for radioimmunoassay. In the current study, tissue extracts from both NIH and Hartley guinea pigs were assayed with three antisera routinely used in our laboratory and one antiserum that had been used in the National Institutes of Health laboratory. We observed that pork-like insulin in tissues from both strains of guinea pigs as determined with the four antisera is less than 0.02 ng/g. We therefore conclude that is is unlikely that nonpancreatic guinea pig tissues contain or synthesize a peptide resembling pork or other non-guinea pig mammalian insulin.

Peptide radioimmunoassays in clinical medicine.

Abstract: The radioimmunoassay technique, first developed for the determination of hormones, has been applied to many substances of biologic interest by clinical and research laboratories around the world. It has had an enormous effect in medicine and biology as a diagnostic tool, a guide to therapy, and a probe for the fine structure of biologic systems. For instance, the assays of insulin, gastrin, secretin, prolactin, and certain tissue-specific enzymes have been invaluable in patient care. Further refinements of current methods, as well as the emergence of new immunoassay techniques, are expected to enhance precision, specificity, reliability, and convenience of the radioimmunoassay in both clinical and research laboratories.