pyrophosphate and Hypoparathyroidism

The purpose of the present investigation was to study various aspects of phosphate metabolism in renal calcium stone patients with special reference to the renal handling of phosphate and its relationship to other renal tubular functions and calcium metabolism. Serum phosphate and the capacity for renal tubular reabsorption of phosphate were lower in stone patients than in controls and decreased with advancing age. Reduced tubular phosphate reabsorption was particularly evident in stone patients with other tubular dysfunctions. Absorptive hypercalciuria was common, but unrelated to the renal tubular reabsorption of phosphate. Parathyroid hyperfunction was not observed in stone formers. Various loads of dietary phosphate resulted in similar renal adaptive responses in controls and stone formers. Orthophosphate supplementation had metabolic consequences with potentially beneficial effects for stone prevention (increased urinary pyrophosphate, decreased urinary calcium). The altered renal handling of phosphate in calcium stone formers may reflect a primary (independent of parathyroid hormone) renal tubular dysfunction in phosphate reabsorption.

Topics: Absorption; Acid-Base Equilibrium; Calcium; Diphosphates; Humans; Hypoparathyroidism; Kidney; Kidney Calculi; Kidney Tubules; Phosphates; Proteinuria; Sodium

Topics: Adrenal Cortex Hormones; Aged; Aging; Bone and Bones; Bone Diseases; Bone Resorption; Calcium; Diphosphates; Female; Humans; Hyperparathyroidism; Hypoparathyroidism; Menopause; Metabolic Diseases; Osteogenesis; Osteomalacia; Osteoporosis; Space Flight

Skeletal abnormalities in 12 patients with primary hyperparathyroidism, five patients with pseudohypoparathyroidism, and three patients with hypoparathyroidism were studied to compare the diagnostic sensitivity of bone radiologic examination to that of radionuclide studies using 99mTc-Sn-pyrophosphate (99mTc-PPi) a skeletal-seeking radiopharmaceutical. The results were compared with bone mineral content as measrued by the Norland--Cameron densitometer. Kinetic data of the blood disappearance and plasma clearance of 99mTc-PPi were obtained and compared with data of control subjects without evidence of parathyroid disease. Bone imaging with 99mTc-PPi may be more sensitive than routine skeletal radiographs and bone mineral analysis for the evaluation of skeletal abnormalities in patients with parathyroid disfunction. The enhanced plasma clearance of the tracer observed in patients with primary hyperparathyroidism may reflect the direct effect of excessive parathyroid hormone on the renal handling of 99mTc-Sn-pyrophosphate.

Topics: Adolescent; Adult; Aged; Bone and Bones; Diphosphates; Female; Humans; Hyperparathyroidism; Hypoparathyroidism; Kinetics; Male; Middle Aged; Minerals; Parathyroid Diseases; Parathyroid Hormone; Pseudohypoparathyroidism; Radionuclide Imaging; Technetium

Topics: Adult; Bone Resorption; Calcium; Diphosphates; Humans; Hypoparathyroidism; Middle Aged; Parathyroid Glands; Parathyroid Hormone; Perfusion