Effect of calcium deprivation on parathyroid hormone mediated bone and kidney contributions to the maintenance of plasma calcium in rats

D. N. Kalu, A. Hadji Georgopoulos, G. V. Foster

Research output: Contribution to journalArticlepeer-review

1 Scopus citations

Abstract

This study was designed to investigate the roles of bone and kidney in the acute regulation of plasma calcium by parathyroid hormone (PTH) during prolonged calcium deprivation. The effect of PTH was assessed by gland ablation. Animals were thyroparathyroidectomized or sham operated and their urine was collected for 3 hr. Subsequently they were anesthetized and bled from the abdominal aorta. In rats fed on a low calcium diet, urinary hydroxyproline excretion was enhanced and, unlike animals fed on a normal diet, decreased 3 hr after thyroparathyroidectomy (TPTX). In addition TPTX decreased plasma calcium by 0.45 mg/100 ml in normal rats compared with 1.94 mg/100 ml in animals fed on a calcium deficient diet. Urinary calcium increased by 161 and 12 μg and accounted for 82 and 1.4% of the fall in plasma calcium in normal and calcium deprived animals respectively. The corresponding contributions of bone were 18 and 98.6%. These findings support the view that with prolonged calcium deprivation in adult rats, the relative contributions of bone and kidney to the acute regulation of the plasma calcium level by PTH are reversed. As a result, bone rather than kidney becomes the more important organ. At the same time non PTH mediated kidney reabsorption of calcium is increased.

Original languageEnglish (US)
Pages (from-to)299-304
Number of pages6
JournalJournal of Endocrinology
Volume64
Issue number2
DOIs
StatePublished - 1975
Externally publishedYes

ASJC Scopus subject areas

  • Endocrinology, Diabetes and Metabolism
  • Endocrinology

Fingerprint

Dive into the research topics of 'Effect of calcium deprivation on parathyroid hormone mediated bone and kidney contributions to the maintenance of plasma calcium in rats'. Together they form a unique fingerprint.

Cite this