Effects of parathyroid hormone on urinary excretion of N-acetyl-beta-D-glucosaminidase in idiopathic hypoparathyroidism and pseudohypoparathyroidism.

N-acetyl-beta-D-glucosaminidase (NAG) is a lysosomal enzyme predominantly located in renal proximal tubules. In idiopathic hypoparathyroidism (IHP), 100 Units of human PTH (1-34) increased urinary excretion of NAG from 0.029 +/- 0.027 to 0.173 +/- 0.035 U/lGF (p less than 0.05) in two patients before treatment and from 0.025 +/- 0.004 to 0.189 +/- 0.092U/lGF (p less than 0.02) in four patients during treatment with active vitamin D3 (1,25(OH)2D3 or 1 alpha OHD3). In pseudohypoparathyroidism (PHP), PTH did not significantly increase the urinary excretion of NAG in one patient with before treatment (0.048 to 0.025 U/lGF) and four patients during treatment with active vitamin D3 (0.018 +/- 0.008 to 0.036 +/- 0.015 U/lGF). Increase in urinary excretion of NAG after injection of PTH may be a new indicator of renal effect of PTH.