The biosynthesis of melanin-concentrating hormone in a fish.
J Neuroendocrinol
; 2(3): 309-15, 1990 Jun 01.
Article
em En
| MEDLINE
| ID: mdl-19215352
ABSTRACT
Abstract This work investigated the biosynthesis of a neurohypophysial hormone, melanin-concentrating hormone (MCH), in the trout. Sephadex G-75 chromatography showed the presence of several large MCH-immunoreactive molecules in hypothalamic and pituitary gland extracts, with different retention times on high-performance liquid chromatography from the mature MCH(1-17). About 10% of the total MCH-immunoreactivity in the hypothalamus was attributable to large molecular weight forms but these contributed less than 1% to the immunoreactivity in the neurointermediate lobe. Both [(35) S]methionine and [(3) H]leucine were injected into the hypothalamus near the MCH perikarya (nucleus lateralis tuberis region) of anaesthetized fish, after which the fish were killed at intervals of up to 8 h post-injection and the basal hypothalami, pituitary pars distales and neurointermediate lobes were extracted in acid. MCH-related immunoprecipitates from these extracts were fractionated by sodium dodecyl sulphate polyacrylamide gel electrophoresis or by Sephadex G-50 chromatography. The results show the incorporation of radiolabel into 15.3 K and 11.3 K precursors within 0.75 h, and their conversion, via several smaller intermediates, to a molecule resembling MCH(1-17). The results are discussed in relation to the known cDNA sequence of salmon MCH. Labelled MCH first appeared in the neurointermediate lobe 4 h after injection, giving an estimated transit rate of 0.4 mm/h.
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Base de dados:
MEDLINE
Idioma:
En
Ano de publicação:
1990
Tipo de documento:
Article