Showing papers by "Rosalyn S. Yalow published in 1978"
TL;DR: The development and techiques of radioimmunoassay are reviewed in the Nobel Prize lecture as discussed by the authors, and the development and technologies of radioIMmunoAssay are discussed in detail.
Abstract: The development and techiques of radioimmunoassay are reviewed in the Nobel Prize lecture.(AIP)
214 citations
TL;DR: Tryptic digestion converted the intact cholecystokinin from all species to a peptide resembling the COOH-terminal octapeptide, which is comparable to that found in the gastrointestinal tract, the traditional site for this peptide.
Abstract: Immunoreactive intact cholecystokinin and its COOH-terminal octapeptide are found in brain as well as in extracts of gut of the monkey, dog, and pig, by using an antiserum with equivalent sensitivities for detecting the octapeptide in free form or incorporated in the intact molecule. The failure to detect intact cholecystokinin in extracts from monkey or dog by using an antiserum developed by immunization with porcine cholecystokinin is presumed to be due to marked species differences in the NH2-terminal portion of the molecule. Tryptic digestion converted the intact cholecystokinin from all species to a peptide resembling the COOH-terminal octapeptide. The amount of cholecystokinin in the brain is comparable to that found in the gastrointestinal tract, the traditional site for this peptide.
96 citations
TL;DR: Subcellular fractionation of the rat cerebral cortex demonstrated the presence of immunoreactive cholecystokinin in the pellet identified by electron microscopy as containing a high proportion of synaptic vesicles, and the evidence for diminished concentration of chole Cyntokinin-like peptides in the brains of hyperphagic mice are consistent with choleCystolinin's suggested role as a neuroregulator for appetite.
Abstract: Subcellular fractionation of the rat cerebral cortex demonstrated the presence of immunoreactive cholecystokinin in the pellet identified by electron microscopy as containing a high proportion of synaptic vesicles. The recovery in this pellet of 40% of the total immunoreactivity in the initial cortical extract is quite comparable to the recovery of other peptides such as vasoactive intestinal polypeptide and somatostatin, which are also located in synaptosomes and for which roles as neuroregulators or transmitters have been suggested. The evidence of concentration of cholecystokinin-like peptides in the synaptosomal pellet is consistent with our earlier demonstration by immunohistochemical techniques of cholecystokinin's presence in rabbit cerebral cortical neurons. These observations and the evidence for diminished concentration of cholecystokinin-like peptides in the brains of hyperphagic mice are consistent with cholecystolinin's suggested role as a neuroregulator for appetite.
81 citations
TL;DR: The studies demonstrate that 8 weeks after hypophysectomy the rats received from commerical sources manifest stress-stimulated plasma corticotropin concentrations about 80% of that found in intact rats in spite of the fact that residual pituitary tissue was not found by visual inspection of the sella.
Abstract: Determination by radioimmunoassay of corticotropin in the brains of rats, rabbits, dogs, monkeys, and human beings reveals that the dimensions within which the hormone is found is about the same for each of these species but that the anatomical regions in which the hormone is found depends on brain size. Corticotropin is widely distributed in the brain of rats but is found only in the hypothalamic region of the primate brain. The patterns of immunoreactivity observed after Sephadex gel filtration confirm that the molecular forms of corticotropin found in extrahypophysial regions are similar to those in the pituitary of each species. These findings suggest that the mammalian pituitary is the sole site of synthesis of the hormone. The observation of persistence of corticotropin in the brains of commerically hypophysectomized rats has been interpreted by others as suggesting diencephalic as well as pituitary origin for this peptide. However, our studies demonstrate that 8 weeks after hypophysectomy the rats we have received from commerical sources manifest stress-stimulated plasma corticotropin concentrations about 80% of that found in intact rats in spite of the fact that residual pituitary tissue was not found by visual inspection of the sella. Scrapings from the sella revealed a corticotropin content up to 5% that of the average rat pituitary.
68 citations
TL;DR: The use of high specific activity [125I]rT3 has permitted the development of a radioimmunoassay with a sensitivity of 1 pg rT3/ml incubation volume.
Abstract: A modified chloramine-T method is described for the preparation of several radioiodothyronines by an exchange reaction, which results in low specific activity preparations, or by an addition reaction, which yields radioiodothyronines with specific activities up to 7 mCi/microgram. Purification by paper chromatography is shown to be more convenient than by LH-20 chromatography and provides better resolution among the various thyronines. Radioiodothyronines with only a single iodine atom in the outer (3,5,3'-triiodothyronine and 3,3'-diiodothyronine) are stable for several months when stored in organic solvents. The least stable radioiodothyronines are those with two 125I atoms in the outer ring (3,3',5'-triiodothyronine (rT3) produced from 3-iodothyronine and thyroxine (T4) from 3,5-diiodothyronine). The stability of rT3 and T4 stored in human plasma at 4 C is much greater than when stored in buffer at the same pH. The use of high specific activity [125I]rT3 has permitted the development of a radioimmunoassay with a sensitivity of 1 pg rT3/ml incubation volume.
58 citations
TL;DR: It is concluded that in a variety of mammalian species most of the immunoreactive secretin extractable from the intestinal tract lies distal to the proximal duodenum and is not distinguishable from duodenal secretin in terms of molecular size.
36 citations
TL;DR: An enzyme has been partially purified from canine and porcine cerebral cortical extracts that differs from trypsin in that it manifests some degree of hormone specificity since it converts Porcine cholecystokinin to smaller immunoreactive forms, but fails to convert big gastrin to heptadecapeptide gastrin.
Abstract: An enzyme has been partially purified from canine and porcine cerebral cortical extracts that differs from trypsin in that it manifests some degree of hormone specificity since it converts porcine cholecystokinin to smaller immunoreactive forms, i.e., the COOH-terminal dodecapeptide and octapeptide fragments, but fails to convert big gastrin (34 amino acids) to heptadecapeptide gastrin. This enzyme is distinguishable from trypsin not only in substrate specificity, but also in several physiochemical properties. It is not inhibited in the presence of concentrations of lima bean trypsin inhibitor sufficient to inhibit 1 mg of trypsin per ml of incubation mixture. It is inactivated when incubated with substrate at 45°C for 1 hr, whereas trypsin remains fully active when incubated under the same conditions at 55°C. The enzyme elutes in the void volume on Sephadex G-50 and G-75 gel filtration. On sucrose gradient centrifugation, the proteolytic activity associated with trypsin is recovered above albumin but that of the solubilized brain enzyme is recovered below gamma globulin. The enzyme is not detectable in splenic extracts, which do contain nonspecific proteases capable of completely degrading cholecystokinin. Further investigation is required to determine whether the enzyme in the gut that converts cholecystokinin to the bioactive and immunoactive COOH-terminal fragments resembles or is different from the brain converting enzyme.
36 citations
TL;DR: Determination by radioimmunoassay of thyrotropin in the brains of rats and humans reveals that the dimensions within which the hormone is found is the same for rodents and primates but that the anatomical regions in which it is found depends on brain size.
31 citations
TL;DR: The development and techiques of radioimmunoassay are reviewed in the Nobel Prize lecture.
Abstract: The development and techiques of radioimmunoassay are reviewed in the Nobel Prize lecture.(AIP)
9 citations
Journal Article•
TL;DR: Radioimmunoassay, a powerful tool for determination of virtually any substance of biologic interest, came into being not by directed design but more as a fall-out from investigations into what might be considered an unrelated study.
Abstract: The development and techiques of radioimmunoassay are reviewed in the Nobel Prize lecture.(AIP)
9 citations
TL;DR: This chapter reviews the theoretical and technical aspects of radioimmunoassay with particular emphasis on the interrelationships between the complications introduced into RIA by the heterogeneity of the peptide hormones and the new insights produced thereby into the related biosynthetic and degradative processes.
Abstract: Publisher Summary This chapter reviews the theoretical and technical aspects of radioimmunoassay (RIA) with particular emphasis on the interrelationships between the complications introduced into RIA by the heterogeneity of the peptide hormones and the new insights produced thereby into the related biosynthetic and degradative processes. The approach has been quite general in its concern with problems and pitfalls common to all assays, whether those in which the reagents are prepared in a research laboratory or those in which commercial sources supply the separate reagents or complete kits. For the latter, there is an additional complication, namely that of quality control of the kits. There are at least two aspects to this problem: quality control by the manufacturer at the time of preparation and the subsequent alterations introduced by handling and mishandling particularly when clinical samples are assayed. For the diagnosis of states of hormonal excess or deficiency the problem is often best solved by clinical rather than chemical control, e.g., by the use of appropriate stimulation or suppression tests, so that the accuracy of the absolute hormonal level is of less significance. For the other substances now measured by RIA, no one has yet provided a uniquely satisfactory answer to the general problem of quality control.