Abstract
Irradiated ergosterol in corn oil was used as a source of vitamin D in the production of Osteitis fibrosa in guinea pigs. Seven groups of adult guinea pigs were given graded doses of activated ergosterol daily. Each group contained 7 pigs weighing in the neighborhood of 500 gm. One group was kept as a control. Complete studies of the serum calcium, inorganic phosphorus, and protein were made previous to autopsy. Sections of the long bones and the chondrosternal junctions of the ribs were fixed in Zenker's fluid and stained with phloxine and methylene blue.
No changes were present where small doses (0.75 mg. to 2 mg. daily) were used. The earliest change visible was a thickening of the fibrous layer of the periosteum of the long bones in the group that had received 5 mg. of irradiated ergosterol.
Changes simulating an Osteitis fibrosa were first seen in the group that received daily doses of 10 mg. of irradiated ergosterol. In 14 days slight fibrous stimulation was present with ingrowth into the marrow cavity. At 25 to 28 days there was resorption of the bony trabeculae together with an increase in the size of the lacunar spaces. These were lined by numerous osteoclasts and showed the presence of fibrous connective tissue ingrowths. The chondrosternal junctions of the ribs were thickened and the osseous portions showed fibrous changes similar to those seen in the long bones.
The group that received 15 mg. daily showed the greatest degree of fibrous change and presented a picture similar to that reported by Jaffe and his workers following the administration of parathormone. In 5 days the chondrosternal junction of the ribs showed fibrous proliferation. With the advance of time in the administration of the oil the bones showed thinning of the corticalis, widespread fibrous connective tissue replacement, and areas of hemorrhage in the marrow cavities.
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