Phosphorus metabolism, comparative

The physiologists and the physiological chemists started the exploration of the chemical composition of bone and later of calcium and phosphorus metabolism. The chemical composition of bones in rickets (Bibra, 1844 Marchand, 1842 Friedleben, 1860), and in osteomalacia (Frey, 1863 Weber, 1867 Huppert, 1867 and others), established the fact that the affected bones, as compared with normal bones, were richer in water and poorer in ash, the constituents of which were mainly calcium and phosphorus. This gave impetus to the study of mineral metabolism, and the early work on calcium metabolism as related to composition of bone dates back to Chossat (1842), Edwards (1861), Weiske (1871), and Voit (1892). 

One remarkable aspect of phosphorus metabolism in the biosphere is the increase in phosphate concentration with depth in the ocean. It appears that the phosphorus gradually passes into the sediment at the bottom and it can be calculated that several times the amount present in the ocean has been removed in this way and been replaced by phosphorus from the lithosphere brought down by die rivers. Compared to the removal of this element the return of phosphorus to the continents is very much in arrears since it depends on the uptake of food from the sea by animals, especially man and birds. The fishing industries of the world take around 60,000 tons of phosphorus (25 to 30 million tons of fish). Sea birds bring back to the land around ten times this figure. 

In their studies on phosphorus metabolism of leukemic tissue Tuttle, Erf, and Lawrence compared the distribution of labeled phosphorus in the... 

We have conducted two human metabolic studies (5,6) to compare the effects of increasing phosphorus intake on calcium utilization in healthy young adults maintained at low (ca. 400 mg/day) and high (ca. 1200 mg/day) levels of calcium intake. Increasing dietary phosphorus, as orthophosphate, caused a slight reduction in fecal calcium and a substantial reduction in urinary calcium losses (Table III). 

There is some evidence, mostly from animal studies, to suggest that high dietary levels of phosphorus, especially if dietary levels of calcium are low, may adversely affect bone mass and calcium metabolism (Greger and Krystofiak 1982). However, in humans there is little direct evidence to indicate that large variations in dietary phosphorus or in the Ca P ratio have any significant influence on calcium utilization or balance (Heaney et al. 1982). Some preliminary findings, however, suggest that the form of phosphorus may influence calcium absorption (Zemel et al. 1982). Hexametaphosphate, as compared with orthophos-... 

The Taiwanese well samples also contained higher average concentrations of phosphorus and boron compared with the U.S. water samples (Fig. 3). Phosphorus has similar chemistry to arsenic and can interfere with arsenic detection and removal. The higher levels of boron may be of interest to health researchers, because boron strongly increases retention of phosphate species in the human body (10), and might be expected to impact metabolism and retention of chemically similar arsenate species as well. 

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