Original Paper

Expression of Pit-1 mRNA and Activin/Inhibin Subunits in Clinically Nonfunctioning Pituitary Adenomas
In situ Hybridization and Immunohistochemical Analysis
Naoko Sanno^a, Akira Teramoto^a, Makoto Sugiyama^a, Akira Matsuno^c, Ichiro Takumi^a, Shigeyuki Tahara^a, R.Yoshiyuki Osamura<sup>b

a</sup> Department of Neurosurgery, Nippon Medical School, Bunkyo-ku, Tokyo,
^b Department of Pathology, Tokai University School of Medicine, Isehara-city, Kanagawa, and
^c Department of Neurosurgery, Teikyo University School of Medicine, Anegasaki, Chiba, Japan

Address of Corresponding Author

Horm Res 1998;50:11-17 (DOI: 10.1159/000023194)

  Key Words

• Pituitary
• Transcriptional factor
• mRNA
• Growth factor
• Pituitary adenoma

  Abstract

The pituitary-specific transcriptional factor Pit-1 is known to play a role in the development and differentiation of pituitary cells. Recent investigations have suggested a role for this transcriptional factor in pituitary adenomas, especially growth hormone (GH)- and prolactin (PRL)-secreting pituitary adenomas. In this study we analyzed the expression of Pit-1 mRNA and its protein in 24 clinically nonfunctioning pituitary adenomas in comparison with normal pituitary glands using in situ hybridization (ISH) and immunohistochemistry (IHC). The interaction between inhibin/activin, a member of the transforming growth factor- family, and Pit-1 was also studied. Immunohistochemically, Pit-1 protein was detected in 9 of 24 adenomas (37.5%), and 8 of these 9 were also positive for the subunit of glycoprotein (SU). The expression of Pit-1 mRNA was detected in 14 of 24 (58.3%) clinically nonfunctioning adenomas, and it was found in all cases which expressed the Pit-1 protein. By the combined ISH and IHC method, Pit-1 mRNA was frequently observed in SU-immunopositive cells in adenomas. The inhibin/activin subunit was detected in all 24 adenomas and the A subunit was detected in 13 of 24 adenomas. The inhibin/activin A subunit was detected frequently with Pit-1 mRNA. From our observations, the inhibin/activin A subunit in nonfunctioning adenomas may have related the expression of Pit-1 mRNA in these adenomas.

  Author Contacts

Naoko Sanno, MD
Department of Neurosurgery
Nippon Medical School, 1-1-5 Sendagi
Bunkyo-ku, Tokyo 113-8602 (Japan)
Tel. +81 3 3822 2131, Fax +81 3 5685 0986

  Article Information

Received: Received: February 24, 1997
Accepted after revision: November 3, 1997
Number of Print Pages : 7
Number of Figures : 5, Number of Tables : 2, Number of References : 34