The influence of scurvy and fall in weight in young guinea pigs on the alkaline phosphatase content of the serum and the zones of provisional calcification

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Abstract
The serum phosphatase of young guinea pigs began to fall after the animals had subsisted on a scorbutic diet for 12 days, at a time when their growth was uninterrupted. The phosphatase content of the costochondral junctions and of the epiphysis of the tibia with the adjoining cartilage did not show any fall before 15-18 days. This latter fall was probably brought about mainly by scorbutic lesions and not by loss in weight. The admn. of a daily dose of 25 mg. L-ascorbic acid to scorbutic guinea pigs maintained for 18 to 21 days on the deficient diet raised the phosphatase content of the 3 tissues very rapidly. Two days'' treatment with L-ascorbic acid increased the phosphatase content of the bones, but not of the serum, to that of normal animals. Further 2 days'' treatment brought the phosphatase content of the serum up to normal values and those of most of the bones to values above those obtained in guinea pigs subsisting on a mixed diet with cabbage ad lib. Maintenance of guinea pigs on a scorbutic diet supplemented with 2 mg. of L-ascorbic acid daily, a dose not sufficient to saturate the tissues, but just adequate to prevent the development of scorbutic lesions, caused no diminution in the tissue phosphatase content. Guinea pigs receiving a scorbutic diet and daily doses as high as 25 mg. L-ascorbic acid showed, 10 days after the withdrawal of L-ascorbic acid, phosphatase values in the 3 tissues lower than those observed in animals which received cabbage ad lib. in the preliminary period. Yet the course of the development of scurvy in both cases was identical. The lower values thus obtained could be brought up to normal by the admn. of a daily dose of only 0.05 mg. L-ascorbic acid during the 10 days'' existence on the scorbutic diet. The phosphatase content of the tissues was not raised in scorbutic guinea pigs 18 hrs. after the intraperit. injn. of 25 mg. L-ascorbic acid which causes saturation of the tissues. It is, therefore, not the direct regulating agent of the phosphatase content of the tissues. The existence of guinea pigs on a scorbutic diet for 15 days had no influence on the phosphatase content of the liver, intestine and kidneys. The latter showed a fall in the premortal phase. The fall in the phosphatase concn. of the serum of guinea pigs caused by a fall in wt. of the animals and not by scurvy was very much less marked than that observed in scorbutic guinea pigs. It is assumed that the fall of the phosphatase in the zones of provisional calcification of scorbutic guinea pigs may be due to a disturbance in the function of the osteoblasts caused by scorbutic lesions. The evidence so far obtained, however, makes it probable that the early diminution in the serum phosphatase is not due to a disturbance in the production of the enzyme, as in the case of the bones, but rather to its removal from the circulation to fulfil some protective function. The evidence also does not exclude the possibility that the serum phosphatase of healthy animals is of vascular origin.