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Science 18 June 1971:
Vol. 172. no. 3989, pp. 1241 - 1243
DOI: 10.1126/science.172.3989.1241
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Articles

Thyrotropin-Releasing Hormone: Biosynthesis by Rat Hypothalamic Fragments in vitro

Maryann Mitnick 1 and Seymour Reichlin 1

1 University of Connecticut School of Medicine, Farmington

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 14C-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 1251-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.


THIS ARTICLE HAS BEEN CITED BY OTHER ARTICLES:
Thyrotropin-releasing hormone precursor: characterization in rat brain.
R. Lechan, P Wu, I. Jackson, H Wolf, S Cooperman, G Mandel, and R. Goodman (1986)
Science 231, 159-161
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Regulation of the Hypophysiotropic Secretions of the Brain.
S. Reichlin (1975)
Arch Intern Med 135, 1350-1361
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Hypothalamic Regulatory Hormones: At least nine substances from the hypothalamus control the secretion of pituitary hormones.
A. V. Schally, A. Arimura, and A. J. Kastin (1973)
Science 179, 341-350
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