Methods in laboratory investigation. Preservation of brush border transport systems for proline and α-methyl-D-glucoside from rat, dog, and human kidney
The effects of freezing renal tissue from rat, dog, and man on the time course of uptake of proline and α-methyl-D-glucoside by subsequently isolated brush border membrane vesicles was examined and compared with uptake patterns by membranes isolated from tissue that had never been frozen. The overshoot phenomenon was used as the critical criterion for viability of the transport systems. Membranes isolated from frozen rat and dog kidney possessed intact transport systems for proline and α-methyl-D-glucoside capable of producing normal or even enhanced overshoot patterns. Freezing human kidney prior to membrane isolation resulted in severe impairment of the vesicle transport capabilities. Freezing a crude membrane suspension, however, allowed the subsequent purification of only partially intact systems.