Related Experiment Videos
Parathyroid hormone and calcitonin secretion in uraemic infants
Insights
Infants with chronic renal failure show high parathyroid hormone (PTH) and calcitonin (CT) levels. Calcium infusion reduced PTH but did not normalize it in all infants, indicating impaired hormonal regulation.
Area of Science:
- Pediatric Nephrology
- Endocrinology
- Biochemistry
Background:
- Chronic renal failure (CRF) in infants can lead to significant disturbances in mineral and bone metabolism.
- Understanding the hormonal regulation of calcium and phosphorus is crucial for managing pediatric kidney disease.
Purpose of the Study:
- To investigate the basal and calcium-stimulated levels of parathyroid hormone (PTH) and calcitonin (CT) in infants with CRF.
- To assess the impact of calcium infusion on mineral levels and hormonal responses in this population.
Main Methods:
- Studied six infants (4-8 months) with CRF.
- Measured serum calcium (Ca), phosphorus (P), alkaline phosphatase, PTH, and CT.
- Analyzed urinary Ca, P, hydroxyproline, and cyclic AMP excretion.
- Administered a 4-hour intravenous calcium gluconate infusion.
Main Results:
- Basal hyperparathyroidism (PTH: 1450-2550 pg Eq/ml) and hypercalcitoninemia (CT: 700-1900 pg/ml) were observed in most infants.
- Urinary excretion of P, hydroxyproline, and cyclic AMP was elevated, while Ca excretion was low.
- Calcium infusion increased serum Ca and CT, and decreased urinary P and cyclic AMP.
- PTH levels decreased but remained elevated, with no suppression in two infants with severe osteodystrophy.
Conclusions:
- Infants with CRF exhibit dysregulation of PTH and CT secretion.
- Calcium homeostasis is impaired, with blunted PTH suppression during calcium loading.
- These findings highlight the complex endocrine challenges in pediatric chronic renal failure.
Abstract:
In six infants aged between 4 and 8 months with chronic renal failure, we have studied blood levels of calcium (Ca), phosphorus (P), alkaline phosphatase, immunoreactive parathyroid hormone (PTH), and calcitonin (CT), as well as urinary excretion of Ca, P, hydroxyproline and cyclic AMP under basal conditions and during an infusion of 20 mg/kg of 10% Ca gluconate in normal saline over 4 h. Under basal conditions four infants had normal serum Ca and P values, alkaline phosphatase levels at the upper limit of normal, and very high PTH (range: 1450--2550 pg Eq/ml) and CT (range: 700--1900 pg/ml) levels. The urinary Ca excretion was low, whereas the urinary excretion of P, hydroxyproline and cyclic AMP was high. During Ca infusion, the total serum Ca and CT levels increased, PTH fell without however reaching the normal upper limit, and urinary P and cyclic AMP excretion decreased. In two infants with osteodystrophy and the highest levels of PTH (2900 and 3500 pg Eq/ml respectively) there was no suppression of PTH during Ca infusion.