Tardivel S, Razanamaniraka L, Drüeke T, Lacour B
Métabolisme Minéral des Mammifères, EPHE, Faculté de Pharmacie, Chatenay Malabry, France.
Pflugers Arch. 1995 Feb;429(4):470-6. doi: 10.1007/BF00704151.
The effect of sorbitol on Ca uptake by isolated ileal epithelial cells was investigated. Intestinal cells were isolated from rat ileum by mechanical vibration. 45Ca uptake was approximately 2 times higher in cells exposed to 200 mM sorbitol of D-alanine than in control cells. This enhancing effect of sorbitol on percentage Ca uptake decreased with increasing Ca concentrations in the incubation medium suggesting an effect on Ca entry velocity. The addition of 10 microM nifedipine or 200 microM verapamil to the incubation medium was devoid of any effect on Ca uptake in ileal cells, whereas 100 microM trifluoperazine or chlorpromazine abolished the stimulatory effect of sorbitol. Finally, the effect of sorbitol on isolated cells was independent of a measurable change of cellular ATP content. In conclusion, the stimulatory effect of sorbitol on ileal Ca uptake is probably exerted through mechanisms other than an increase in intracellular ATP concentration. Sorbitol may enhance enterocyte Ca transport via a direct interaction with calmodulin and/or the Ca pump. It may also exert its effect through an inhibition of the basolateral Na Ca exchanger.
研究了山梨醇对离体回肠上皮细胞钙摄取的影响。通过机械振动从大鼠回肠分离出肠细胞。暴露于200 mM山梨醇或D-丙氨酸的细胞中45Ca摄取量比对照细胞高约2倍。随着孵育培养基中钙浓度的增加，山梨醇对钙摄取百分比的这种增强作用降低，表明对钙进入速度有影响。向孵育培养基中添加10 microM硝苯地平或200 microM维拉帕米对回肠细胞的钙摄取没有任何影响，而100 microM三氟拉嗪或氯丙嗪则消除了山梨醇的刺激作用。最后，山梨醇对分离细胞的作用与细胞ATP含量的可测量变化无关。总之，山梨醇对回肠钙摄取的刺激作用可能是通过细胞内ATP浓度增加以外的机制发挥的。山梨醇可能通过与钙调蛋白和/或钙泵直接相互作用来增强肠上皮细胞的钙转运。它也可能通过抑制基底外侧钠钙交换器发挥作用。
