Effect Of CT And CGRP On NaPi-Ⅱb Expression And Phosphours Absorption Of The Intestinal Epithelia Cells In Porcine

The low efficienty utilization in the monogastic animals, the shortage of phosphorus feed and waste, and the manure phosphorus discharge pollution to the environment, has been the importment problems facing the breeding.How to improve the effective utilization of phosphorus, and clarify the molecular of phosphorus absorption is the key to solve these problems.Sodium dependent phosphorate cotransporter Ⅱb(NaPi-Ⅱb) as the main control sodium dependent phosphorus absorption(Na-Pi) cotransporter found in the intestinal currently, the expressioin was influenced by many kinds of factors.As the important regulatory factors of the calcium and phosphorus, calcitonin(CT) and calcitonin gene related peptide (CGRP) were detected to study they regulation of sodium dependent phosphorate cotransporter Ⅱb (NaPi-Ⅱb) expressionand phosphorus absorption of the intestinal epithelial cells(IEC) in porcine in vitro.Experiment one The3-8genenration cells were randomly allotted into contronl treatment, CT (1×10-8～1×10-12mol/L) treatments and CGRP (1×10-7～1×10-11mmol/L) treatments by single factor random allotment, each treatments consisted of6replicates.The cell growth curve was determined by the MTT method. The cell morphology were observed and phosphorus concentration in the cell supernatant were determined, after24hours of CT&CGRP training. The results show that no significant differences were found in the cell growth. The1×10-9、1×10-10mol/L CT significantly decreased phosphorus absorption (P<0.01). All levels of CGRP significantly increased phosphorus absorption (P<0.01)Experiment two The effects of CT on the NaPi-Ⅱb expression was conducted to investigate by real time-PCR and Western blot after24hours of CT training on the logarithmic phase cells. It shows that, compared with the control group, the CT treatments showed no significant difference in NaPi-Ⅱb mRNA and NaPi-Ⅱb protein expression.Experiment three The effects of CGRP on the NaPi-Ⅱb expression was conducted to investigate by real time-PCR and Western blot after24hours of CGRP training on the logarithmic phase cells. It shows that, compared with the control group, all CGRP levels induced NaPi-Ⅱb protein abundance except the1×10-10mmol/L treatment (P<0.05).the1×10-8、1×10-9mmol/L treatment significant enhanced the NaPi-Ⅱb mRNA expression (P <0.05) And the promoting effect of NaPi-Ⅱb protein expression was significant then the NaPi-Ⅱb mRNA of the1×10-8mmol/L treatment CGRP.In summary, CT and CGRP have no difference on cells growth. Compared with the control, CT inhibits the phosphorus absorbtion, but has no significant difference on the NaPi-Ⅱb expression, implying that CT regulates phosphorus absorbtion not induced by NaPi-Ⅱb cotransporter. CGRP can increase the phosphorus absorbtion by stimulate the NaPi-Ⅱb expression in the porcine intestinal epithelial cell, and the1×10-8、1×10-9mmol/L treatments has the most significant promoting effects. Sugesting that CGRP in a certan concentration range can increase phosphorus transmembrane transport by stimulating NaPi-Ⅱb transcription activity. From the expression of NaPi-Ⅱb mRNA and protein, the regulation of CGRP to the Na-Pi transport is a kind of after-transcription regulation.