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Basal and hormone-induced urinary cyclic AMP in children with renal disorders
Insights
Urinary cyclic AMP levels in children with kidney concentrating defects showed varied hormonal responses. Measurement of urinary cyclic AMP is not currently valuable for diagnosing these conditions.
Area of Science:
- Pediatric Nephrology
- Endocrinology
- Biochemistry
Background:
- Cyclic adenosine monophosphate (cAMP) plays a crucial role in renal function and hormone signaling.
- Urinary cAMP excretion is influenced by antidiuretic hormone (ADH) and parathyroid hormone (PTH).
- Previous studies suggested unresponsiveness to ADH and PTH in nephrogenic diabetes insipidus (NDI).
Purpose of the Study:
- To investigate urinary cyclic AMP (cAMP) excretion in children with normal renal function, congenital nephrogenic diabetes insipidus (NDI), and renal failure with impaired concentrating ability.
- To evaluate the response of urinary cAMP to antidiuretic hormone (ADH) and parathyroid hormone (PTH) in these pediatric groups.
- To assess the diagnostic utility of urinary cAMP measurements in differentiating renal concentrating defects.
Main Methods:
- Collected urine samples from normal children, children with congenital NDI, and children with moderate renal failure.
- Measured urinary cyclic AMP (cAMP) levels under basal conditions.
- Administered antidiuretic hormone (ADH) and parathyroid hormone (PTH) and re-measured urinary cAMP excretion.
Main Results:
- Contrary to previous reports, hereditary congenital NDI patients did not exhibit complete unresponsiveness to ADH and PTH.
- Patients with structural renal disorders and defective urine concentrating ability showed diminished hormonal responses in urinary cAMP excretion.
- No significant value was found in measuring individual urinary cAMP levels for diagnosing renal concentrating disorders.
Conclusions:
- Careful definition and diagnosis of nephrogenic diabetes insipidus (NDI) are essential.
- Current data suggest urinary cyclic AMP (cAMP) measurement lacks diagnostic value in differentiating individual cases of renal concentrating defects.
- Further research is needed to clarify the role of cAMP in NDI and related conditions.
Abstract:
The excretion of cyclic AMP in urine has been examined in normal children and in children with nephrogenic diabetes insipidus or moderate renal failure (predominantly defective concentrating ability) under basal conditions and in response to antidiuretic hormone (ADH) and parathyroid hormone (PTH). In contrast to other reported data, we could not confirm an ADH- and (PTH-unresponsiveness in hereditary, congenital nephrogenic diabetes insipidus, but our patients with structural renal disorders characterized by a defective urine concentrating ability did have reduced hormonal responses. It seems necessary to define nephrogenic diabetes insipidus very carefully, and until more data are collected, there appears to be no value in the measurement of urinary cyclic AMP level in the individual patient in the differential diagnosis of disorders due to renal concentrating defects.