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Triiodithyronine (T3) enhances the stimulatory effect of 1,25-dihydroxyvitamin D3 on calbindin-D28K mRNA expression in kidney and intestine but not in cerebellum of the chick |
A. Sechman, K. Shimada, N. Saito, T. Ieda, T. Ono |
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Abstract |
The present study was conducted to investigate the role of thyroid hormones in the regulation of gene expression of calbindin-D28k(CaBP-D28K) in the chicken. By employing slot blot and RIA analyses, levels of CABP-D28K mRNA and CaBP-D28K protein in the intestine, kidney, cerebellum and liver were measured 6 and 12 h after i.m. injection of 1, 25-dihydroxyvitamin D3[1, 25 (OH)2D3; 250 ng/chick] and 3, 5, 3-triiodothyronine(T3; 500 ng/chick) in one-day-old chicks. The abundant messages of CaBP-D28K mRNA were detected in the intestine, kidney and cerebellum while there was little message in the liver. After 1, 25 (OH)2D3 treatment (6 + 12 hours),, levels of CaBP-D28K mRNA increased in the intestine, but there was no change in the mRNA levels in the kidney and cerebellum. Although T3 alone had no effect on CaBP-D28K mRNA levels, simultaneous administration of T3 enhanced the 1, 25 (OH)2D3 effect of levels of CaBP-D28K mRNA in the intestine both 6 and 12 h post-treatment, and in the kidney 12 h post-treatment. At a protein level, co-treatment with 1, 25 (OH)2D3 and T3 elicited a significant increase in CaBP-D28K expression in the intestine 12 h post-treatment, as compared to treatment with only 1, 25 (OH)2D3, whereas no differences were observed in the CaBP-D28K protein levels in the kidney and cerebellum. These results suggest that thyroid hormones may play a synergistic role with 1, 25 (OH)2D3 for CaBP-D28K gene expression in the intestine and kidney in chicks |
Keywords:
Calbindin-D28k; Triiodothyronine(T3); 1, 25-Digydroxycholecalciferol; Gene Expression; Chick |
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