The Membrane Control of Bone Potassium

Geisler, Jan; Neuman, W. F.

doi:10.3181/00379727-130-33618

Cited by 28 publications

(8 citation statements)

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“…Based on the rapidity by which the skeleton can correct for deviations in serum calcium, it is believed that the instantaneous moment to moment regulation of serum calcium is handled by movement of calcium across this large quiescent surface area and not by the active remodeling mechanisms [17,18]. Several lines of evidence suggest that bone fluid is compartmentalized [19][20][21][22][23]. The first compartment probably constitutes the fluid in bone canaliculi and the water bound to the mineral and the osteoid [24].…”

Section: Discussionmentioning

confidence: 99%

Acute Effect of Prolactin on Bone 45Ca Accumulation in Rats.

1997

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Abstract.In an attempt to evaluate the acute effect of PRL on bone turnover, experiments were performed in sexually mature female Wistar rats which were given an intraperitoneal (ip) administration of 1.25 mM CaC12 solution containing 6 ,uCi 45Ca. Dose response study showed a two fold higher rate of 45Ca uptake in 30 min by control trabecular bones (sternum and vertebrae 5-6) compared with control compact bones (femur and tibia). Femur exhibited a dose dependent increase in 45Ca uptake in response to pharmacological doses of 0.01 and 0.02 mg PRL/100 g body weight but was less responsive to 0.04 mg PRL / 100 g body weight. Tibia only responded with increased 45Ca uptake to 0.02 and 0.04 mg PRL / 100 g body weight while trabecular bones were unresponsive. By varying the intervals between administration of 45Ca (0 min) and PRL (0, 30 or 60 min) and bone harvesting (30, 60 or 90 min), it was found that 0.01 mg PRL/100 g body weight had a biphasic action on 45Ca movement. It initially enhanced 45Ca influx into femur by 30 min followed by an accelerated 45Ca efflux from femur back to the circulation.It could be concluded that PRL acutely stimulated calcium turnover in compact bone.

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Section: Discussionmentioning

confidence: 99%

Acute Effect of Prolactin on Bone 45Ca Accumulation in Rats.

1997

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“…Triffitt and Cafias [14] and their coworkers found inexplicably high concentrations of this ion in bone, particularly growing bones. That this K excess was under cellular control was shown by Geisler [15], Ramp [16], and Scarpace [17]. Although repeatedly assailed, this information has stood and is still unexplained today.…”

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confidence: 98%

Blood: Bone equilibrium

Neuman

1982

Calcif Tissue Int

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“…The active transport system for potas-sium that Neuman has repeatedly demonstrated [3,12,13,16] and that he has attributed to the bone membrane [16] would cause an electrical potential difference positive with respect to the bone fluid side of the membrane; whereas the calcium pump proposed by Talmage [2, 10, I 1] would cause a potential difference of opposite sign. The effectiveness of a pump in producing a measurable potential is dependent on the activity of that pump, the magnitude of passive ionic leaks through the membrane, and the existence of opposing pumps that transport like charges in the opposite direction or unlike charges in the same direction.…”

Section: Introductionmentioning

confidence: 99%

Electrical potential difference across bone membrane

1980

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The control of ion fluxes to and from bone has important implications to mineralization and calcium homeostasis. Since ionic transport frequently results in an electrical potential difference across the layer of cells lining bone surfaces, knowledge of this potential is critical to understanding the means of regulation of ionic concentrations in the interior bone fluid phase. This work presents a determination of a metabolism-related electrical potential difference by a thermodynamic argument based on the distribution of charged and uncharged tracers between the bone extracellular fluid compartment and the bathing medium. For embryonic chick calvaria whose viability was assured by oxygen consumption measurements, an electrical potential of 4 mV was determined, positive with respect to the bone fluid compartment. This measurement is shown to be consistent with the active transport of K+ ion into the interior of bone; the potential developed by this transport process will then exclude from the interior phase a passively leaked Ca2+ ion.

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The Membrane Control of Bone Potassium

Cited by 28 publications

References 0 publications

Acute Effect of Prolactin on Bone 45Ca Accumulation in Rats.

Acute Effect of Prolactin on Bone 45Ca Accumulation in Rats.

Blood: Bone equilibrium

Electrical potential difference across bone membrane

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