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Biomedical subjects

S Reichlin

Publications and source records attributed to S Reichlin.

At least 217 records · Page 12Linked to original sources
PubMed1971

Thyrotropin-releasing hormone: biosynthesis by rat hypothalamic fragments in vitro.

Biosynthesis of thyrotropin-releasing hormone (L-pyroglutamyl-L-histidyl-L-proline amide) in vitro was studied. Rat hypothalamic fragments were incubated in Krebs-Ringer bicarbonate buffer that contained either (14)C-labeled proline, histidine, or glutamic acid (the three probable precursor amino acids,) and for control purposes each of 16 other naturally occurring amino acids. A number of labeled peptides were synthesized. With the use of synthetic thyrotropin-releasing hormone, detected by the Pauly reagent or with (125)1-labeled thyrotropin-releasing hormone as a marker, thin-layer chromatograms, paper electrophoresis, and carboxymethyl cellulose ion exchange chromatography revealed that only proline, histidine, and glutamic acid were consistently incorporated into peptides associated with the thyrotropin-releasing hormone region. This synthesizing activity was found in stalk median eminence, ventral hypothalamus. and dorsal hypothalamus but not in neural lobe or cerebral cortex. Because the biosynthetic peptide has identical properties with L-pyroglutamyl-L-histidyl-L-proline amide, it is probable that rat thyrotropin-releasing hormone is similar or identical to both bovine and porcine thyrotropin-releasing hormone and that the native material is present in the pyroglutamyl form in tissues.

Animals↗
PubMed1970

Thyrotropin secretion in rats after hypothalamic electrical stimulation or injection of synthetic TSH-releasing factor.

Plasma thyroid-stimulating hormone (TSH) levels, as measured by radioimmunoassay, begin to rise within 5 minutes after initiation of electrical stimulation of the medial-basal hypothalamus, become significantly elevated at 10 minutes, and reach a peak at 10 to 25 minutes. Intravenous administration of synthetic thyrotropin-releasing factor induces a marked rise in plasma thyroidstimulating hormone which is maximal within 5 minutes after administration. These data are interpreted to indicate that there are neuronal structures within the medial-basal hypothalamus which release preformed thyrotropin-releasing factor. The claim (based on bioassay data) that pyroglutamyl-histidyl-proline amide is a potent thyrotropin-releasing factor has also been confirmed by using a highly specific immunoassay system.

Animals↗