Parathyroid hormone-like biological activity in urine

Area of Science:

• Endocrinology
• Biochemistry
• Urology

Background:

• Parathyroid hormone (PTH) regulates calcium and phosphate metabolism.
• Hyperparathyroidism involves excessive PTH production, leading to hypercalcemia.
• Identifying biomarkers for hyperparathyroidism is crucial for diagnosis and management.

Purpose of the Study:

• To investigate the parathyroid hormone-like biological activity in concentrated urine samples.
• To correlate urinary bioactivity with different calcium regulatory states, including hyperparathyroidism.

Main Methods:

• Assessing bioactivity by measuring plasma calcium increase in chickens after intravenous urine injection.
• Testing urine samples from hypoparathyroid patients, normal subjects, and patients with primary and secondary hyperparathyroidism.
• Evaluating the effect of trypsinization on the urinary bioactivity.

Main Results:

• Urine from primary and secondary hyperparathyroid patients exhibited significantly higher PTH-like bioactivity compared to normal subjects.
• Urine from hypoparathyroid patients showed the lowest bioactivity.
• Surgical removal of hyperparathyroid adenomas led to a decrease in urinary bioactivity.
• Trypsinization reduced the bioactivity, indicating a peptide nature of the substance.

Conclusions:

• Concentrated urine contains a parathyroid hormone-like substance with hypercalcemic activity.
• Urinary bioactivity levels correlate with the state of parathyroid function.
• This peptide substance may serve as a potential biomarker for hyperparathyroidism.