Endocrine influences on the activity ratio of 90Y to 90Sr in the rat skeleton after incorporation of 90Sr.

The quantitative distribution of 90Y to 90Sr was affected after surgical removal of the parathyroids, adrenals, and male and female gonads. The activity ratio of 90Y to 90Sr (Q) and the concentration in bone of 90Sr, expressed in per cent of injected dose per 100 mg of bone ash, were determined. Parathyroidectomy and adrenalectomy reduced while ovariectomy raised the value of Q. Adrenalectomy and ovariectomy increased the concentration of 90Sr in bone. Some aspects of the metabolism of the two nuclides are discussed.