Acta Neuropathologica

, Volume 93, Issue 1, pp 43–49

Characterization of spherical amyloid protein from a prolactin-producing pituitary adenoma

  • D. R. Hinton
  • R. K. Polk
  • K. D. Linse
  • M. H. Weiss
  • Kalman Kovacs
  • J. A. Garner
Regular paper

DOI: 10.1007/s004010050581

Cite this article as:
Hinton, D., Polk, R., Linse, K. et al. Acta Neuropathol (1996) 93: 43. doi:10.1007/s004010050581

Abstract

Prolactin (PRL)-producing pituitary adenomas are in some cases associated with deposition of abundant spherical amyloid; however, the origin of the amyloid has not been established. In this report, a PRL-producing pituitary adenoma composed almost entirely of spherical amyloid was analyzed biochemically. The tumor was removed surgically from a 56-year-old man. Immunohistochemical analysis revealed that residual tumor cells were strongly positive for PRL, while the spherical amyloid was not. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis revealed a band of approximately 4 kDa associated with the amyloid, which was not present in a non-amyloid producing prolactinoma. The 4-kDa band is similar in size to other known amyloidogenic peptides. Immunoblot analysis of the tumor material using polyclonal anti-human PRL antibodies revealed a small amount of normal-sized PRL; however, the abundant 4-kDa band was nonimmunoreactive. Amino acid sequencing showed that this peptide represents the first 34 amino acids of the intact PRL protein with a predicted size of 4313 Da. The presence of a small amount of normal-sized PRL in this tumor, as well as elevated circulating levels of PRL implies that intact PRL is being abnormally processed in the formation of spherical amyloid.

Key words AmyloidProlactinImmunoblotAminoacid sequencing

Copyright information

© Springer-Verlag Berlin Heidelberg 1996

Authors and Affiliations

  • D. R. Hinton
    • 1
  • R. K. Polk
    • 3
  • K. D. Linse
    • 4
  • M. H. Weiss
    • 2
  • Kalman Kovacs
    • 5
  • J. A. Garner
    • 3
  1. 1.Department of Pathology, University of Southern California School of Medicine, 2011 Zonal Ave. HMR 209, Los Angeles, CA 90033, USA Tel.: 1-213-342-1342; Fax: 1-213-342-3396US
  2. 2.Department of Neurological Surgery, University of Southern California School of Medicine, Los Angeles, California, USAUS
  3. 3.Department of Cell and Neurobiology, University of Southern California School of Medicine, Los Angeles, California, USAUS
  4. 4.Institute for Cellular and Molecular Biology, The University of Texas at Austin, Austin, Texas, USAUS
  5. 5.Department of Pathology, St. Michaels’s Hospital, University of Toronto, Toronto, Ontario, CanadaCA