Abstract
The work of Howland and Kramer 1 on the level of the inorganic phosphate in the blood in human rickets, and some confirmatory experiments undertaken by Hess 1 led to the conclusion that during the period of active rickets in children, the inorganic phosphate of the blood is reduced, and that during the process of cure by either sunlight or cod-liver oil, the phosphate rises again to its normal level.
Since the experimental rickets produced in rats is comparable in most important respects to human rickets, it was thought of interest to determine whether the same changes in blood phosphate could be demonstrated in rats. In applying the work of Howland and Kramer to experimental rat rickets, we have obtained results which on the whole agree very well with those of theirs reported at a recent meeting of the Society of Biological Chemists.
Because of the small quantities of blood which can be obtained from the animals, it seemed advisable to make the determinations on whole blood rather than plasma if possible. Experiments undertaken to show the relative distribution of the inorganic phosphate in plasma and whole blood indicate that the level of the phosphate is practically the same inside and outside the cells and is maintained at a constant level from day to day. Therefore, as far as the inorganic phosphate is concerned, it is immaterial whether the determinations are made on whole blood or plasma.
(By the colorimetric method of Bell and Doisy. 2 )
Table I shows average figures for the inorganic phosphate in the blood of rats on rickets-producing, normal and high phosphorus diets.
We find that in general a reduction in the inorganic phosphate of the blood runs parallel to the degree of severity of the rachitic lesions.
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