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Horm Metab Res 1983; 15(6): 299-304
DOI: 10.1055/s-2007-1018700
© Georg Thieme Verlag, Stuttgart · New York

Humoral Hypercalcemia Caused by a Rat Leydig-Cell Tumor is Associated with Suppressed Parathyroid Hormone Secretion and Increased Urinary cAMP Excretion

A. M. Spiegel1 , A. W. Saxe2 , L. J. Deftos3 , M. F. Brennan2
  • 1Metabolic Diseases Branch, NIADDK, U.S.A.
  • 2Surgery Branch, NCI, National Institutes of Health, Bethesda, Maryland, U.S.A.
  • 3University of California and San Diego VA Medical Center, La Jolla, California, U.S.A.
These studies were presented in part at the third annual meeting of the American Society for Bone and Mineral Research, abstract 39A, 1981.
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Publication History

1982

1982

Publication Date:
14 March 2008 (online)

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Summary

We studied the effect of a transplantable Leydig-cell tumor (Rice H-500) on serum calcium, parathyroid hormone (PTH), and urinary cAMP in intact Fischer-344 rats. The tumor caused rapid and severe hypercalcemia (control = 10.5±0.1 mg/dl) [mean ± S.E.] vs. 14.6±0.9 at day 12 post tumor inoculation) without evidence of metastasis. Progressive renal impairment and death generally occurred within 15 days of tumor inoculation. Serum PTH declined from control values before hypercalcemia occurred and was significantly reduced in tumorbearing hypercalcemic rats (mean = 60±8% of control values). Urinary cAMP excretion was increased in tumor-bearing rats (mean at day 12 post inoculation = 12.2±1.4 nmol/dl creatinine clearance vs. control = 6.2±0.2) and correlated positively with serum calcium. The Rice H-500 Leydig-cell tumor appears to secrete a humoral factor capable of causing hypercalcemia. This factor may also increase urinary cAMP excretion in a manner analogous to PTH, but it is not detected by PTH radioimmunoassay.

Key-Words:

Tumor Hypercalcemia - Parathyroid Hormone - Cyclic AMP