Tardivel S, Fournier P, Dupuis Y, Nabarra B, Drueke T, Lacour B
Laboratoire EPHE, Métabolisme Minéral des Mammifères, Physiologie, Faculté de Pharmacie, Chatenay-Malabry, France.
Calcif Tissue Int. 1994 Apr;54(4):304-11. doi: 10.1007/BF00295955.
Ligated ileal loops, 30 cm in length, of 4-month-old male Wistar rats were instilled with 3 ml of a 10 mM CaCl2 solution (added with 0.25 muCi 45Ca) in the absence (control) or presence of 100mM sorbitol, L-xylose, or creatine. Ileal calcium (Ca) transport, measured by plasma 45Ca appearance, was found to be similar 30 minutes after fluid instillation in all four instances. However, thereafter, 45Ca appearance in plasma did not increase further in control animals whereas it increased twice as much during the subsequent 30 minutes in the presence of sorbitol, L-xylose, or creatine. However, when loops of similar length were instilled with only 1.0 ml of such solutions, the sorbitol effect was already observed during the first 30 minutes. The stimulation of ileal Ca absorption induced by the presence of sorbitol appeared to be due to a cellular effect, associated with a decreased flux across the paracellular pathway, as indicated by 3H-mannitol absorption. The presence of sorbitol in instilled ileal solution induced a significant decrease in luminal Na, K, bicarbonate, and Cl concentrations at each time point studied (30, 60, 120, or 240 minutes after instillation). Thirty minutes after instillation, no difference in soluble Ca concentration was observed between control and experimental rats. After 60 minutes, Ca concentration was dramatically decreased in control rats but it remained nearly constant in experimental animals. Thus, the presence of substances enhancing ileal Ca transport favored the maintenance of soluble Ca in ileal solution during longer time periods than their absence. In the ileal enterocyte, these substances induced a twofold increase of ATP content compared with controls.(ABSTRACT TRUNCATED AT 250 WORDS)
对4月龄雄性Wistar大鼠30厘米长的结扎回肠袢分别在无（对照）或有100mM山梨醇、L-木糖或肌酸存在的情况下注入3毫升10mM氯化钙溶液（添加0.25微居里45Ca）。通过血浆45Ca出现量测定的回肠钙（Ca）转运在所有四种情况下液体注入后30分钟时相似。然而，此后，对照动物血浆中45Ca出现量不再进一步增加，而在山梨醇、L-木糖或肌酸存在的情况下，在随后的30分钟内增加了两倍。然而，当用仅1.0毫升此类溶液注入相似长度的肠袢时，在最初30分钟内就已观察到山梨醇效应。山梨醇的存在诱导的回肠Ca吸收刺激似乎是由于细胞效应，与跨细胞旁途径通量降低有关，如3H-甘露醇吸收所示。注入回肠溶液中的山梨醇在每个研究时间点（注入后30、60、120或240分钟）导致管腔Na、K、碳酸氢盐和Cl浓度显著降低。注入后30分钟，对照大鼠和实验大鼠之间可溶性Ca浓度未观察到差异。60分钟后，对照大鼠中Ca浓度急剧下降，但在实验动物中仍几乎保持恒定。因此，与不存在增强回肠Ca转运的物质相比，这些物质的存在有利于在更长时间段内维持回肠溶液中的可溶性Ca。在回肠肠细胞中，与对照相比，这些物质使ATP含量增加了两倍。（摘要截断于250字）
