A method was developed for the quantification of human growth hormone ( hGH ) by protein purification and isotope dilution-high performance liquid chromatography mass spectrometry ( HPLC-IDMS ) . The hGH was purified and fractionated by fast protein liquid chromatography ( FPLC ) , then hGH molecular weight was accurately determined by Fourier transform ion cyclotron resonance mass spectrometer ( FTICR-MS). The purified hGH was hydrolyzed and the separation was performed on an KINETEX C18 column (150 mmí2 mm I. D. , 2. 6 μm) with water ( containing 0. 1% TFA) and acetonitrile isocratic solution as the mobile phase at a flow rate of 0 . 2 mL/min and 40℃. The electrospray source was operated in the positive ion mode, and monitored in the multiple reaction monitoring ( MRM) mode. The measured hGH molecular weight by FTICR-MS was only 0. 31 Da difference from theoretical value. Three amino ( proline, valine and phenylalanine) were clearly separated by isocratic elution within 5 min. Under the optimized conditions, the content of hGH was 186 . 80 μg/g with a RSD of 0 . 5%. The detection results of hGH in international comparison by this method were consistent with the reference value, which validated the feasibility of the established method. The developed method is simple, practical, accurate, reliable and reproducible, and can be used for the hGH quantitation of pure hGH CRM to provide reference for the routine detection of hGH.

Objective To clarify the association between chondroitin-4-O-sulfotransferase-3 (CHST13) and hepatoma metastasis by the research of differential expression of CHST13 in MHCC97-H and MHCC97-L human hepatocarcinoma cell lines,which have high and low metastatic potential,respectively,and to confirm novel target of hepatoma metastasis and anti-tumor therapy.Methods The differential expressions of CHST13 in MHCC97-H and MHCC97-L human hepatocarcinoma cell lines were analyzed by real-time PCR,Western blot.CHST13 was silenced using RNA interference approach to detect the invasive ability in vitro and tumorigenicity in vivo in MHCC97-L cells.Results The expression of CHST13 was different in MHCC97-L cells,as compared to those in MHCC97-H cells.Knockdown of CHST13 expression enhanced MHCC97-L cells invasion and tumorigenicity both in vitro (t =2.8,P =0.005) and in vivo (t =2.5,P =0.01).The quantity of cells which crossed basement membrane increased [(30 ± 3):(14 ± 2)],and the average weight of tumor increased [(0.9 ± 0.10) g:(0.5 ± 0.06) g].Conclusion The differential expressions of CHST13 in human hepatocarcinoma cell lines correlate with tumor invasion and tumorigenicity,and it is expected to be a novel target for the treatment of hepatocellular carcinoma.