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Urinary cyclic AMP excretion during volume expansion in the rat
Canadian Journal of Physiology and Pharmacology
|June 1, 1977
Summary
Volume expansion with saline transiently increased urinary cyclic adenosine monophosphate (cAMP) excretion in normal rats, possibly due to parathyroid hormone release. This effect was absent in parathyroidectomized rats, though both groups showed a later decrease in cAMP excretion.
Area of Science:
- Physiology
- Renal Physiology
- Endocrinology
Background:
- Volume expansion is a common physiological challenge.
- Urinary cyclic adenosine monophosphate (cAMP) is a key second messenger involved in various cellular processes, including renal function.
- The role of parathyroid hormone (PTH) in regulating cAMP excretion during volume expansion is not fully understood.
Purpose of the Study:
- To investigate the effect of acute volume expansion using 0.9% saline on urinary cyclic AMP excretion in rats.
- To explore the potential involvement of parathyroid hormone in the observed changes in cAMP excretion.
Main Methods:
- Acute volume expansion was induced in normal and parathyroidectomized rats by infusing 0.9% saline solution (10% body weight over 1 hour).
- Urinary cyclic AMP excretion was measured in picomoles per minute during control periods and at various time points during and after volume expansion.
- Comparisons were made between normal and parathyroidectomized rat groups.
Main Results:
- In normal rats, urinary cAMP excretion significantly increased during the initial phase of volume expansion but returned to baseline levels before decreasing significantly by the end of the infusion.
- In parathyroidectomized rats, urinary cAMP excretion did not increase during volume expansion and showed a significant decrease by the end of the infusion period.
- A transient increase in cAMP excretion was observed in normal rats, suggesting a potential role for parathyroid hormone release.
Conclusions:
- The transient increase in urinary cyclic AMP excretion during volume expansion in normal rats may be mediated by parathyroid hormone release.
- The underlying mechanisms responsible for the subsequent decrease in urinary cAMP excretion observed in both normal and parathyroidectomized rats following volume expansion remain unclear and warrant further investigation.