Expression And Localization Of Stanniocalcin-1 In Kidney And Duodenum Of Neonatal Dairy Cows

Stanniocalcin-1 (STC-1) is a peptide hormones that was firstly idendified in the bony fish specific corpuscle of stannius(CS). Later, it was reported that STC gene express in human and a variety of mammals and had some protein and mRNA distribution reports. STC-1 participates in calcium and phosphorus metabolism. STC-1 inhibits the absorption of calcium, promotes the absorption of phosphate, inhibits the excretion of phosphate. The structure and function of muscle and blood vessel formation and reproductive process were also affected by STC-1. In dairy cows, exploring STC-1 expression in the horizontal of molecular and tissue level is significant to study the mechanism of calcium and phosphorus metabolism. On the other hand, it may provide a new way to explore prevention and control of calcium and phosphorus metabolism disease.To test STC-1 expression or not, and distribution in kidney and duodenum of Chinese Holstein cows from the gene level, the total RNA of kidney and duodenum of experimenting one day old dairy cows was extracted, the purpose cDNA was synthesized through the established PCR reaction system. The result showed that, STC-1 gene expressed in kidney and duodenal of the Chinese Holstein cows. The cloned purpose cDNA was connected to T vector, and was transformed and sequenced. Sequence analysis showed that, the partial sequence of STC-1 gene nucleotide sequence homology is 100% corresponding with Bos taurus.In calcium and phosphorus metabolism, the duodenum was the most important calcium and phosphorus absorption site, and kidney was important organ of re-absorption and excretion. To explore the physiological role of STC-1 protein in diary cow's calcium and phosphorus metabolism, STC-1 protein was tested in the kidney and duodenum of one day old Chinese Holstein cows. The results of immunohistochemistry showed that the epithelial cells of kidney proximal tubule and distal tubule have significant brown staining, mainly in the cytoplasm of epithelial cells. And glands and duodenal goblet cells of the intestinal showed clear brown staining. STC-1 mRNA was tested in the kidney and duodenum by in situ hybridization. The results showed that, the epithelial cells in kidney proximal tubule, cortical thick ascending limb have conspicuous hybridization signals, and with weak hybridization signals in the distal tubule. And no positive brown staining was showed in the glomerular regions. In the duodenum, it is significant hybridization signal in the edge of goblet cells and intestinal glands. In this experiment, it was the first time prove that STC-1 gene expressed in kidney and duodenum of the Chinese Holstein cows, and also was the first localization of STC-1 protein and mRNA in the kidney and duodenal tissues of Chinese Holstein cows. The results provided new materials for further studying of STC-1 gene structure, expression in different tissues and expression patterns, created the conditions for researching the physiological role of STC-1, and provided new informations for exploring prevention and treatments of calcium and phosphorus metabolic diseases of dairy cows.