Electrolyte Composition of Bone and the Penetration of Radiosodium and Deuterium Oxide Into Dog and Human Bone 12

The Mineral Content of Normal Human Bone1

“…The amounts of water found are similar to those reported by Edel-man, James, Baden and Moore when the large variance is considered (11). The concentrations of Ca, P and CO3 found agree closely with those reported elsewhere (5,(9)(10)(11)13). Despite the differences in Ca and P concentrations between bones, the molar Ca to P ratios were 1.76, 1.72 (13).…”

“…Klement, in 1936, also conducted a comprehensive investigation of mineral content, but his material was limited to three samples of skull, and two each of pelvis and femur (3). In recent years, further reports of human bone composition have appeared (4)(5)(6)(7)(8)(9)(10)(11)(12). However, these latter observations have not been wholly satisfactory, in that the number of samples analyzed were few and the determinations were limited to two or three minerals.…”

Exercise-Associated Hyponatremia

“…An intriguing possibility discussed by Noakes et al (34) is that some athletes are able to mobilize sodium from internal stores that otherwise are osmotically inactive. This exchangeable sodium store has been described by Edelman and colleagues, Titze and colleagues, and Heer and colleagues (81)(82)(83)(84)(85)(86). For example, in the study by Heer et al (86) participants were fed a diet of varying sodium amounts with a fixed amount of water ingestion.…”

“…Despite these conditions, serum sodium levels remained constant without a concomitant increase in TBW. These studies indicated that up to one fourth of the total body sodium may exist in bone and cartilage stores that are not osmotically active (i.e., in an insoluble crystal compound) but potentially recruitable into an osmotically active form (81)(82)(83). In rats, this nonosmotically active sodium may reside bound to skin proteoglycans (87,88).…”

“…Therefore, athletes who gain TBW and maintain a normal serum sodium concentration are able to mobilize this store of exchangeable sodium, whereas athletes who develop EAH either cannot mobilize the exchangeable pool or sodium or may osmotically inactivate sodium (34). The factors that govern the exchange of sodium between these compartments is unknown but may involve hormonal factors such as angiotensin II or aldosterone (81)(82)(83)(84)(85)(86). The magnitude of this effect in athletes is large with up to 700 mmol of sodium being mobilized from the osmotically inactive pool in the calculations by Noakes et al (34).…”