| 2195 Hormone Modulation of Branching Morphogenesis in Fetal Mouse Submandibular Glands | ||
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S. MARUYAMA1, T. NAGAO1, T. NAKA1, S. OHKAWA1, H. SAKAGAMI1, K. KURIHARA1, K. TONOSAKI1, S. YOKOSE1, T. KATAYAMA1, M. KASHIMATA2, and E.W. GRESIK3, 1Meikai University School of Dentistry, Sakado,Saitama, Japan, 2Asahi University, Gifu, Japan, 3City University of New York Medical School, USA yObjectives:z Branching morphogenesis of fetal mouse submandibular gland (SMG) is a basic developmental and cytodifferential process of ducts and acini formation.The branching morphogenesis depends on reciprocal epithelio-mesenchymal interaction, and is stimulated by many growth factors including IGF-1. We have reported that the branching process of fetal SMG is modulated by androgen and thyroid hormones. We investigated here the induction mechanisms of branching morphogenesis by two hormones, 5&alpha-dihydrotestosterone (DHT) and triiodothyronine (T3). yMethods:zThe fetal normal SMG (the 13th day of gestation), or its mesenchyme and epithelium tissues, which were separated by digestion with Dispase 1, were organ-cultured for 0-48 hrs on Anocel filters in the culture chamber with DHT (10-20&mug/ml) or T3 (1-2&mug/ml). Normal SMG rudiments were also incubated with anti-IGF or anti IGF binding protein (IGF-BP, type1-4) antibody (2&mug/ml, type1: 5&mug/ml, type 2:1&mug/ml, type3: 2&mug/ml, type 4:5&mug/ml respectively) in serum-free BGJb medium. The branching morphogenesis of SMG was scored under photomicroscope, and IGF-1 content in SMG was measured by RIA. Expression of IGF-1 and IGF-BP type 1-4 mRNAs were measured by RT-PCR and real time PCR. yResults:z DHT and T3 stimulated the branching morphogenesis of unseparated SMG, but not that of separated tissues. The effects of DHT and T3 on the SMG were inhibited by anti-IGF-1, but not by anti-EGF. Moreover, the effect of DHT was inhibited by anti-IGF-BP type 2 and 3, whereas that of T3 was inhibited by anti-IGF-BP type 2-4. The concentration of IGF-1 in the SMG was increased by DHT and T3. The expression of IGF-1 and IGF-BPtype2-3 mRNAs in SMG was enhanced by DHT and T3. yConclusion:zThese results suggest that IGF-1, but not EGF, is involved in the branching morphogenesis induced by DHT and T3, and pharmacological actions of these two hormones are regulated by different subtypes of IGF-BPs | ||
| Seq #241 - Salivary Gland Development and Regeneration II 2:00 PM-4:00 PM, Friday, 11 March 2005 Baltimore Convention Center Exhibit Hall E-F | ||
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