Iseki K, Sugawara M, Saitoh H, Miyazaki K, Arita T
Department of Pharmacy, Hokkaido University Hospital, School of Medicine, Hokkaido University, Japan.
J Pharm Pharmacol. 1989 Sep;41(9):628-32. doi: 10.1111/j.2042-7158.1989.tb06544.x.
The transport characteristics of amino beta-lactam antibiotics, ampicillin and cephradine, have been examined and compared with that of glycylglycine using brush border membrane vesicles isolated from rat small intestine. The initial rate of glycylglycine uptake was markedly stimulated in the presence of an inward H+ gradient compared with the uptake rates in the absence of an H+ gradient. With the same H+ gradient the stimulation of cephradine uptake was lower and ampicillin uptake was not altered. Cephradine uptake, however, was greater than that of glycylglycine in both vesicular conditions ((pH)i greater than (pH)o and (pH)i = (pH)o). Inhibitory effects of dipeptides, ampicillin and cephradine on the initial uptake of glycylglycine were also examined. Glycylglycine uptake was significantly decreased in the presence of L-phenylalanylglycine or carnosine. Ampicillin and cephradine did not alter the uptake of glycylglycine. These results suggest that the contribution of the inward H+ gradient to the permeation of ampicillin, cephradine and glycylglycine across the rat small intestinal brush border membranes is different for each of the substances examined.
已使用从大鼠小肠分离的刷状缘膜囊泡研究了氨基β-内酰胺抗生素氨苄西林和头孢拉定的转运特性，并与甘氨酰甘氨酸的转运特性进行了比较。与不存在H⁺梯度时的摄取速率相比，在存在内向H⁺梯度的情况下，甘氨酰甘氨酸的初始摄取速率明显受到刺激。在相同的H⁺梯度下，头孢拉定摄取的刺激作用较低，而氨苄西林的摄取未改变。然而，在两种囊泡条件下（内部pH大于外部pH和内部pH等于外部pH），头孢拉定的摄取均大于甘氨酰甘氨酸的摄取。还研究了二肽、氨苄西林和头孢拉定对甘氨酰甘氨酸初始摄取的抑制作用。在L-苯丙氨酰甘氨酸或肌肽存在的情况下，甘氨酰甘氨酸的摄取显著降低。氨苄西林和头孢拉定未改变甘氨酰甘氨酸的摄取。这些结果表明，内向H⁺梯度对氨苄西林、头孢拉定和甘氨酰甘氨酸跨大鼠小肠刷状缘膜渗透的贡献因所研究的每种物质而异。
