Identification of midkine-expressing cells in the anterior pituitary gland of adult rats

Program: Abstracts - Orals, Featured Poster Presentations, and Posters
Session: MON 142-166-Hypothalamus-Pituitary Development & Biology
Monday, June 17, 2013: 1:45 PM-3:45 PM
Expo Halls ABC (Moscone Center)

Poster Board MON-166
Ken Fujiwara*, Kotaro Horiguchi, Depicha Jindatip, Floren Ly and Takashi Yashiro
Jichi Medical University School of Medicine
Midkine (MK) is a secreted heparin-binding growth factor that modulates proliferation and migration of various cells. MK is highly expressed during embryogenesis and down-regulated at birth. In the adult, MK shows a very restricted pattern of expression with the highest mRNA levels in the intestine and low levels in the brain, thyroid, lung, stomach, colon, spleen, kidney, and bladder. We recently found the expression of MK in both anterior and posterior pituitary glands of adult rats. In the present study, we characterized MK-expressing cells in the pituitary glands of adult rats. MK positive cells were detected in the anterior pituitary glands by using in situ hybridization with a digoxigenin-labeled cRNA probe. To characterize MK positive cells, we also performed double-staining of MK mRNA and pituitary hormones or S100 protein, which is a marker of folliculostellate (FS) cells. MK mRNA was identified in S100-protein-positive cell. By cell sorting, we separated FS cells and hormone-producing cells from S100b-GFP transgenic rat that expresses GFP specifically in FS cells. The mRNA and protein of MK were detected in FS cells by real-time RT-PCR and Western blotting, respectively. Conversely, its receptor, the receptor-type tyrosine phosphate zeta (RPTPζ) was expressed in sorted GFP-negative cells that include hormone-producing cells. These results suggest that MK is produced in the FS cells of adult anterior pituitary gland and it may act locally on hormone-producing cells.

Nothing to Disclose: KF, KH, DJ, FL, TY

*Please take note of The Endocrine Society's News Embargo Policy at

Sources of Research Support: Grant-in-Aid for Young Scientists (B) 24790199 from the Ministry of Education, Culture, Sports, Science and Technology of Japan; promotional funds for the Keirin Race of the Japan Keirin Association
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