SUBCELLULAR LOCALIZATION OF α‐MELANOCYTE‐STIMULATING HORMONE IN THE RAT HYPOTHALAMUS

A. Barnea, C. Oliver, J. C. Porter

Research output: Contribution to journalArticlepeer-review

61 Scopus citations

Abstract

Homogenates of male rat hypothalami were fractionated by means of differential centrifugation, and α‐melanocyte‐stimulating hormone (α‐MSH) in the various fractions was quantified by radioimmunoassay. Of the total quantity of α‐MSH in the homogenate, 36% was recovered in the 11,500 g pellet and 31% sedimented between 11,500 and 105,000 g. α‐MSH was not detected in the 105,000 g supernatant fluid. When the 900 g supernatant fluid was fractionated on continuous sucrose density gradients at non‐equilibrium conditions, two populations of particles containing α‐MSH were observed. When fractionated at equilibrium conditions, the two populations were recovered in a single band. These sedimentation characteristics indicate that the particles that contain α‐MSH differ in size but are similar in density. After hypo‐osmotic shock, the large particles containing α‐MSH were not demonstrable, whereas the small particles appeared to be resistant to such treatment. In their sedimentation, the particles containing α‐MSH were indistinguishable from particles containing thyrotropin releasing hormone (TRH) but were separable from those that contained luteinizing hormone releasing hormone (LHRH). It is suggested that the large particles containing α‐MSH are synaptosomes.

Original languageEnglish (US)
Pages (from-to)619-624
Number of pages6
JournalJournal of Neurochemistry
Volume29
Issue number4
DOIs
StatePublished - Oct 1977

ASJC Scopus subject areas

  • Biochemistry
  • Cellular and Molecular Neuroscience

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