Abstract: Objective To investigate the relation between plasma membrane Ca SUP>2+/SUP>ATPase (PMCA) activity and stanniocalcin-1 (STC1) gene expression in enterocytes in toad, EM>Bufo bufo gargarizans/EM> .Methods Based on tolerance test in this study, 72 adult toads were randomly divided into a high calcium group ［tap water supplied with 0.1mol/L CaClSUB>2/SUB>), a low calcium group (tap water supplied with 0.03mol/L ethylene diamine tetraacetic acid(EDTA)］ and a control group (tap water). The small intestinal mucosa was excised on the pre-exposure and post-exposure 12, 24, 48, 72, 96, 120, 144 hours, respectively. Both plasma Ca2 level and PMCA activity were detected with colorimetry, and STC1 gene expression was analyzed with semi-quantitative RT-PCR. Results The results showed that: (1) After 0.1mol/L CaClSUB>2/SUB> exposure, the plasma calcium level increased at the 12th and 24th hour (EM>P/EM><0.05), restored to the normal level at the 48 th hour, and went up at the 72 th hour (EM>P/EM><0.05). Additionally, PMCA activity was enhanced and STC1 gene expression was up-regulated during 12th-48th hour after 0.1mol/L CaClSUB>2/SUB> exposure. (2) After 0.03 mol/L EDTA exposure, the plasma calcium level decreased, but both PMCA activity and STC1 gene expression did not change.Conclusion High plasma calcium level stimulates PMCA activity and STC1 expression in enterocytes, whereas up-regulated STC1 may inhibits PMCA activity i

Key words: Stanniocalcin, Plasma membrane Ca SUP>2+/SUP> -ATPase, Enterocyte, Semi-quantitative RT-PCR, EM>Bufo bufo gargarizan/EM>