Tests for Hyperparathyroidism: Tubular Reabsorption of Phosphate, Phosphate Deprivation, and Calcium Infusion*†

“…Serum phosphorus (8), serum alkaline phosphatase (9), urinary calcium (10), inulin clearance (11), and percentage tubular reabsorption of phosphorus (TRP)' (12) were measured using standard methods. Serum immunoreactive parathyroid hormone (IPTH) concentration was determined before and after the administration of estrogen in eight patients and anabolic hormone in seven patients by the method of Arnaud, Tsao, and Littledike (13).…”

Section: Methodsmentioning

confidence: 99%

Short- and long-term effects of estrogen and synthetic anabolic hormone in postmenopausal osteoporosis

Riggs¹,

Jowsey²,

Goldsmith³

et al. 1972

J. Clin. Invest.

225

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A B S T R A C T In 29 women with postmenopausal osteoporosis, the proportion of total bone surface undergoing resorption or formation was evaluated by microradiography of iliac crest biopsy samples before and after shortterm (21-4 months) and long-term (26-42 months for estrogen and 9-15 months for anabolic hormone) treatment. After estrogen administration, values for boneresorbing surfaces decreased, although less prominently after long-term than after short-term therapy. The magnitude of this decrease was positively correlated with the pretreatment value for bone-resorbing surfaces (P < 0.001). When the pretreatment value for bone-resorbing surfaces was used as a covariable, estrogen and anabolic hormone appeared to be equally effective. For boneforming surfaces, short-term therapy with either hormone had no effect but long-term therapy significantly decreased the values. Serum immunoreactive parathyroid hormone (IPTH) increased significantly after estrogen therapy; the change in IPTH was inversely related to the change in serum calcium (P < 0.001, sign test). We conclude that the primary effect of sex hormones in postmenopausal osteoporosis is to decrease the increased level of bone resorption, perhaps by decreasing the responsiveness of bone to endogenous parathyroid hormone. However, this favorable effect, at least in part, is negated after long-term treatment by a secondary decrease in bone formation. Our data are consistent with the concept that the maximal benefit that can be derived from sex hormone therapy in postmenopausal osteoporosis is arrest or slowing of the progession of bone loss.

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“…It is well established that the urinary excretion of Pi is related to its dietary intake. This relation has been described by balance and clearance techniques in normal human adults and patients with parathyroid disease (1)(2)(3)(4)(5), in newborn children (6), and in both intact and parathyroidectomized rats (1,7,8). In these studies it has mostly been shown that dietary Pi (9).…”

Section: Introductionmentioning

confidence: 99%

Inorganic phosphate homeostasis. Renal adaptation to the dietary intake in intact and thyroparathyroidectomized rats.

Tröhler¹,

Bonjour²,

Fleisch³

1976

J. Clin. Invest.

182

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A B S T R A C T The possibility of renal tubular adaptation to variations in dietary inorganic phosphate (Pi) was investigated in intact and thyroparathyroidectomized (TPTX) rats pair-fed diets containing low, normal, and high amounts of Pi for periods up to 10 days. Clearances were measured before and during acute i.v. infusions with Pi in conscious animals. Thus tubular reabsorption of phosphate (TRPi) could be assessed over a wide range of plasma phosphate concentrations ([Pt]Pi). It was found that the renal tubule could adapt its capacity to transport Pi according to the dietary Pi: TRPt was always higher, for a given [Pt]P1, in the animals fed low than in those fed higher Pi diets. This diet-induced modification also occurred in the absence of thyroparathyroid glands, in the presence of the same calcemia and urinary pH, and during marked extracellular volume expansion. A time-course study in rats TPTX both before and during the administration of the experimental diets showed that a difference in the tubular handling of Pi was detectable as early as 3 days after switching the animals from a normal to low-or high-Pi diets. These results indicate that factors other than parathyroid hormone are implicated in the tubular response to variations in the dietary intake of inorganic phosphate.

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Tests for Hyperparathyroidism: Tubular Reabsorption of Phosphate, Phosphate Deprivation, and Calcium Infusion*†

Cited by 120 publications

References 11 publications

Vitamin D-Resistant Rickets: The Effect of Calcium Infusion on Phosphate Reabsorption *

Vitamin D-Resistant Rickets: The Effect of Calcium Infusion on Phosphate Reabsorption *

Short- and long-term effects of estrogen and synthetic anabolic hormone in postmenopausal osteoporosis

Inorganic phosphate homeostasis. Renal adaptation to the dietary intake in intact and thyroparathyroidectomized rats.

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