Aluminum parathyroid hormone

As discussed in Section 2.4.1, there are some data that suggest that aluminum absorption can be enhanced by parathyroid hormone and vitamin D, but the data are inconclusive. 

Commissaris RL, Cordon JJ, Sprague S, et al. 1982. Behavioral changes in rats after chronic aluminum and parathyroid hormone administration. Neurobehav Toxicol Teratol 4 403-410. 

McCormack KM, Ottosen LD, Sanger VL, et al. 1979. Effect of prenatal administration of aluminum and parathyroid hormone on fetal development in the rat (40493). Proc Soc Exp Biol Med 161 74-77. 

Morissey J, Slatopolsky E. 1986. The effect of aluminum on parathyroid hormone secretion. Kidney Int 29S 41-48. 

Aluminum binds diatomic phosphates and possibly depletes phosphate, which can lead to osteomalacia. High aluminum serum values and high aluminum concentration in the bone interfere with the function of vitamin D. The incorporation of aluminum in the bone may interfere with deposition of calcium the subsequent increase of calcium in the blood may inhibit release of parathyroid hormones by the parathyroid gland. The mechanism by which aluminum concentrates in the brain is not known it may interfere with the blood brain barrier. 

Wang M, Hercz G, Sherrard DJ, Maloney NA, Maloney NA, Segre GV, et al. Relationship between intact 1-84 parathyroid hormone and bone histomor-phometric parameters in dialysis patients without aluminum toxicity. Am J Kidney Dis 1995 26 836-44. 

Shore D, King SW, Kaye W, et al Serum and cerebrospinal fluid aluminum and circulating parathyroid hormone in primary degenerative (senile) dementia, in Aluminum Toxicity. Edited by Liss L. Park Forest South, IL, Pathotox, 1980a, pp 55-63 Shore D, Millson M, Holtz JL, et al Serum aluminum in primary degenerative dementia. Biol Psychiatry 15 971-977, 1980b... 

The chemical form of aluminum affects aluminum absorption. Furthermore, the parathyroid hormones, vitamin D and iron seem to affect aluminum absorption."" In the human bloodstream aluminum is stored mainly in the Uver, kidneys, spleen, bones, and heart and brain tissues. 

Slatopolsky EA. (1999). Renagel , a nonabsorbed calcium- and aluminum-free phosphate binder, lowers serum phosphorus and parathyroid hormone. Kidney Int 55, 299-307. 

The precise mechanism and the localization of the absorption for orally taken aluminum are not known so far. It is assumed, however, that the aluminum is absorbed in the stomach and the duodenum, possibly in the proximal jejunum as well. The absorbed amount depends on the solubility of the aluminum compound and the respective gastrointestinal pH level. In addition, iron and fluorine increase the enteral absorption. Furthermore, the aluminum intake might be influenced by the parathyroid hormone and vitamin D. The daily aluminum intake via nutrition depends on eating habits and is estimated at an average of 5-10 mg/day less than 1% of this amount is absorbed. 

With increasing aluminum intake, the highest aluminum concentrations are observed in bone, in the spleen, in the liver, and in the heart muscle. Patients with chronic renal failure who are medicated orally and/or parenterally with medication containing aluminum show in addition an increased aluminum level in the brain. It is assumed that these patients have an increased permeability of the blood-brain barrier for aluminum. Moreover, an increased aluminum level occurs also in bone. Hormone imbalances (parathyroid hormone) and a vitamin D deficiency are discussed as causes for this. 

The amount of aluminum absorbed from the gastrointestinal tract may be dependent on certain factors. For example. Mayor et ai 56,57 report that increased parathyroid hormone treatment causes increased intestinal aluminum absorption and higher brain aluminum concentrations in rats given oral aluminum. They also observed that parathyroid hormone withdrawal in rats resulted in a rapid decrease of brain aluminum concentration independent of dietary aluminum. Those authors suggest that reduced parathyroid hormone aids in reducing brain aluminum accumulation, and that both Alzheimers disease and dialysis encephalopa-... 

Mayor G. H. Remedy R. F. Sprague S. M. and Lovell K. L. (1980) Central nervous system manifestations of oral aluminum effect of parathyroid hormone. Neurotoyicol. 1, 33-42. 

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