Urinary cyclic nucleotide levels in patients with hyper- and hypothyroidism

Area of Science:

• Endocrinology
• Metabolism
• Urology

Background:

• Thyroid hormones significantly influence cellular metabolism.
• Cyclic nucleotides like cAMP and cGMP are crucial intracellular messengers involved in various physiological processes.
• Alterations in thyroid function may impact cyclic nucleotide metabolism and excretion.

Purpose of the Study:

• To investigate urinary cyclic adenosine monophosphate (cAMP) and cyclic guanosine monophosphate (cGMP) excretion in patients with hyperthyroidism and hypothyroidism.
• To explore potential sex-related differences in these urinary nucleotide levels.
• To compare findings with those observed in hypoparathyroidism.

Main Methods:

• Measurement of urinary cyclic AMP, cyclic GMP, and creatinine.
• Analysis of data from 38 hyperthyroid patients, 32 hypothyroid patients, and 57 normal subjects.
• Calculation of cyclic nucleotide to creatinine ratios to account for urinary concentration variations.

Main Results:

• Urinary cAMP and cGMP excretion were elevated in female hyperthyroid patients but not males.
• Cyclic nucleotide/creatinine ratios were increased in both male and female hyperthyroid patients, partly due to decreased creatinine excretion.
• Hypothyroid patients showed decreased cAMP excretion, with no significant change in cAMP/creatinine ratios; cGMP alterations were minor and sex-dependent.

Conclusions:

• Hyperthyroidism and hypothyroidism are associated with significant alterations in urinary cyclic nucleotide levels.
• Sex-specific differences exist in the urinary excretion patterns of cyclic nucleotides in thyroid disorders.
• Observed changes in cyclic nucleotide levels in thyroid dysfunction resemble those seen in parathyroid disorders.