Figure 5. Antiproliferative effect of 1,25 diOH vitamin D on parathyroid cells. Reduction of parathyroid cell proliferation in response to increasing medium 1,25diOH vitamin D (calcitriol) concentrations in the incubation milieu of a human parathyroid cell culture system, with parathyroid cells derived from hyperplastic parathyroid tissue of patients with severe secondary uremic hyperparathyroidism. From Roussanne et al (75).