Localization of inhibin/activin subunits in normal pituitary and in pituitary adenomas

Pituitary. 2000 Nov;3(3):131-9. doi: 10.1023/a:1011431123208.

Abstract

The localization of inhibin/activin (I/A) subunits was investigated in human normal adenohypophysial cells and in 87 pituitary adenomas of different types, using immunohistochemistry. Monoclonal antibodies directed against alpha, beta A and beta B subunits of I/A were employed. In normal pituitary, alpha subunit of inhibin was detected only in FSH-positive gonadotrophs, while beta A subunit of I/A was expressed in FSH-positive gonadotrophs, GH-cells and in a few PRL-cells. beta B subunit was found in FSH-positive gonadotrophs, TSH-cells and a few LH-positive gonadotrophs. The three subunits of I/A were detected in the majority of nonfunctioning tumors, while functioning adenomas showed a significantly lower expression. This study shows that alpha, beta A and beta B subunits of I/A are expressed by specific adenohypophysial cell types and that they are characteristically present in nonfunctioning adenomas. These results suggest that inhibins and activins may play a role in the local regulation of pituitary hormonal secretion both in normal adenohypophysial cells and in pituitary adenomas.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Activins
  • Adenoma / metabolism*
  • Adolescent
  • Adult
  • Aged
  • Aged, 80 and over
  • Child
  • Female
  • Humans
  • Immunohistochemistry
  • Inhibins / metabolism*
  • Male
  • Middle Aged
  • Pituitary Gland / metabolism*
  • Pituitary Neoplasms / metabolism*
  • Protein Isoforms / metabolism
  • Tissue Distribution

Substances

  • Protein Isoforms
  • Activins
  • Inhibins