Hydrochlorothiazide lowers urinary hydroxyproline in parathyroidectomized rats.

This study was undertaken to examine the effects of hydrochlorothiazide treatment on urinary hydroxyproline excretion in parathyroidectomized rats. Urinary hydroxyproline (mumol/24 hr) fell significantly in thiazide-treated rats compared with control animals (5.66 +/- 0.37 versus 7.30 +/- 0.6, P less than 0.05, means +/- SEM). This fall in hydroxyproline excretion occurred without a decrease in glomerular filtration rate. It is concluded that the ability of thiazide diuretics to reduce urinary hydroxyproline excretion is not dependent upon suppression of parathyroid hormone-mediated bone turnover.