Scarpace P J, Neuman W F
Calcif Tissue Res. 1976 Apr 20(2):151-8.
An attempt was made to quantitate in vitro the unidirectional fluxes of Ca2+ and Pi across periosteal and endosteal membranes of frontal bones from calvaria of 20 day chick embryos. The influx of Ca2+, as previously reported, seemed to be passive [12]. The uncoupler, CCCP, had no effect on the influx of Ca2+, but increased both the endosteal and periosteal effluxes. La2+ decreased the influx of Ca2+. The influx of phosphate was also passive and proportional to the concentration of phosphate. The influx was unaffected by either iodoacetate or CCCP, but increased when the periosteal and endosteal membranes were removed; the efflux of phosphate was greater from the endosteal side and was unaffected by CCCP, while iodoacetate increased both the periosteal and endosteal effluxes. The evidence presented refutes the generally accepted hypothesis that Ca2+ (or phosphate) fluxes into and out of bone are governed by a pumpleak system. However, the increase in rate of influx when the cellular layers are removed indicates that the periosteum and endosteum constitute an important structural conponent in the maintenance of bone mineral and its equilibration with the circulation.
人们试图在体外对20日龄鸡胚颅骨额骨的骨膜和骨内膜膜上Ca2+和Pi的单向通量进行定量。如先前报道，Ca2+的流入似乎是被动的[12]。解偶联剂CCCP对Ca2+的流入没有影响，但增加了骨内膜和骨膜的流出。La2+降低了Ca2+的流入。磷酸盐的流入也是被动的，并且与磷酸盐的浓度成正比。流入不受碘乙酸或CCCP的影响，但当骨膜和骨内膜膜被去除时增加；磷酸盐从骨内膜侧的流出更大，并且不受CCCP的影响，而碘乙酸增加了骨膜和骨内膜的流出。所提供的证据反驳了普遍接受的假说，即Ca2+（或磷酸盐）进出骨骼的通量受泵-漏系统控制。然而，当细胞层被去除时流入速率的增加表明骨膜和骨内膜在维持骨矿物质及其与循环的平衡中构成重要的结构成分。
