Serum PTH, 25OHD, 1,25(OH)D, and 1,25(OH)D/25OHD Ratio in 37 Subjects With Primary Hyperparathyroidism Prior to Supplementation and 3 to 6 Months After Weekly Supplementation With 50,000 Units of Vitamin D (Ergocalciferol). Here, PTH is linked to primary hyperparathyroidism.