Effects of parathyroid hormone on remodeling of iliac trabecular bone packets in patients with primary hyperparathyroidism

In order to determine the effects of parathyroid hormone on bone formation, mean wall thickness (MWT) of trabecular bone packets was measured on transilial undecalcified bone biopsies from 26 patients (14 females and 12 males) with primary hyperparathyroidism (HPT). Mean value of MWT in HPT patients (45.2 +/- 5.8 microns) was found to be significantly lower than in 35 controls (50.1 +/- 8.5 microns) (p less than 0.001). This difference is due to a significant reduction of MWT in HPT females before 50 years of age (46.0 +/- 2.3 microns) when compared with controls (56.2 +/- 7.1 microns; p less than 0.05), whereas there is no significant difference of average MWT in males of any age or in females after 50. These reductions of MWT could explain the rarefaction of spongy bone previously noticed in HPT females younger than 50 years. Furthermore, because of the mild depression of the osteoblastic activity measured by tetracycline double-labeling in HPT, the osteoblastic formation period was determined to be shortened in females before 50 years, and lengthened in females after 50 years of age and in males of any age. This could explain the anabolic effects of 1-34 hPTH fragment on trabecular bone volume in postmenopausal osteoporosis.