Oral Peptones Load in Normocalcemic and Hypercalcemic Primary Hyperparathyroidism and Healthy Subjects

The purpose of this study is to assess if subjects with hyperparathyroidism with normal serum calcium levels have different responses in the calcium regulating hormonal handling compared to a) patients with primary hyperparathyroidism and high serum calcium levels; b) healthy subjects. The differences will be evaluated with oral peptones load and subsequent blood samples collected every 15 minutes for two hours. Ionized calcium, phosphate, gastrin and PTH levels will be evaluated.