Abstract
Summary
Four Cebus monkeys, 2 males and 2 females, were maintained on a caseincorn oil diet containing 0.5% cholesterol for 86 weeks. For the greater part of this time the diet contained uracil (0.5-0.75%) and during 2 short feeding trials of 3 and 5 weeks duration orotic acid was also included in the diet (0.5%-l%). Uracil produced a further increment in serum cholesterol elevation beyond that due to dietary cholesterol alone as well as an elevation of serum urea. In one female concomitant feeding of orotic acid at the 1% level lowered the serum cholesterol. At autopsy the 2 females demonstrated large colloid goiters while the thyroids of the 2 males showed a mixed picture of both colloid goiter and that of colloid-poor hyperplasia. In one of the males this latter process was extreme and could not be distinguished from early carcinoma. It is assumed that these thyroid changes resulted from ingestion of uracil (or uracil and cholesterol), though the possible role of orotic acid cannot be completely excluded. Speculations on the pathogenesis of the two types of thyroid change are discussed as well as comparisons of the above results with those seen in rats.
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