Immunohistochemical localization of γ-melanocyte-stimulating hormone in the rat pituitary gland

https://doi.org/10.1016/0167-0115(81)90002-1Get rights and content

Abstract

A third melatropin fragment named γ-MSH has been described in the N-terminal portion of the common precursor of bovine ACTH and β-LPH by Nakanishi et al. (Nakanishi, S., Inoue, A., Kita, K., Nakamura, M., Chang, A.C.Y., Cohen, S.N. and Numa, S., Nature, 278 (1979) 423–427). In order to determine if immunoreactive γ-MSH was present in the rat pituitary gland and to accurately localize this peptide, an immunocytochemical localization of γ-MSH was conducted at both light and electron microscopic levels. Specific immunostaining was detected in stellate cells scattered throughout the pars distalis and in all the cells of the pars intermedia. At the ultrastructural level, immunoreactive γ-MSH was only observed in the lipocorticotrophs. Using serial ultrathin sections, it was shown that the secretory granules which contain ACTH were also labeled for γ-MSH. These results suggest that fragment(s) of the common precursor of ACTH and β-LPH and/or the whole common precursor is released with peptides of known biological activity.

References (22)

  • R.E. Mains et al.

    Coordinate synthesis of corticotropins and endorphins by mouse pituitary tumor cells

    J. Biol. Chem.

    (1978)
  • I. Tanaka et al.

    Existence of γ-melanotropin (γ-MSH)-like immunoreactivity in bovine and human pituitary glands

    Biochem. Biophys. Res. Commun.

    (1980)
  • S. Benjannet et al.

    A novel human pituitary peptide containing the γ-MSH sequence

    Nature

    (1980)
  • M. Chrétien et al.

    Isolation, purification and characterization of gamma-lipotropic hormone from sheep pituitary glands

    Can. J. Biochem.

    (1976)
  • M. Chrétien et al.

    From β-lipotropin to β-endorphin and pro-opiomelacortin

    Can. J. Biochem.

    (1979)
  • P. Crine et al.

    Biosynthesis of β-endorphin from β-lipotropin and a large molecular weight precursor in rat pars intermedia

  • P. Crine et al.

    Processing of two forms of the common precursor to α-melanotropin and β-endorphin in the rat pars intermedia

    Eur. J. Biochem.

    (1980)
  • B.A. Eipper et al.

    Existence of a common precursor to ACTH and endorphins in the anterior and intermediate lobe of the rat pituitary

    J. Supramol. Struct.

    (1978)
  • R.C. Graham et al.

    The early stages of absorption of injected horseradish peroxidase in the proximal tubules of mouse kidney: ultrastructural cytochemistry by a new technique

    J. Histochem. Cytochem.

    (1966)
  • J. Guy et al.

    Localization of a fragment (16K fragment) of the common precursor for adrenocorticotropin (ACTH) and β-lipotropin (β-LPH) in the rat and human pituitary gland

    J. Cell Biol.

    (1980)
  • R. Leclerc et al.

    Immunocytochemical localization of ACTH and β-LPH

    • Cited by (0)

    View full text
    Copyright © 1981 Published by Elsevier B.V.