Effect of calcium loading test on calcitonin and katacalcin levels before and after surgical removal of the ovaries.

Since the role of gonadal steroids and their interrelation with calcium regulating hormones is not clear, we performed a prospective study to investigate the effects of gonadectomy on the calcitonin (CT)/katacalcin (KT) system using 1 minute calcium infusion as a provocative test. Seventeen women aged 26-51 years awaiting abdominal hysterectomy with bilateral oophorectomy were included in the study and the same protocol was repeated 14 days after surgery. CT and KT concentrations were determined radioimmunologically after reverse phase extraction of serum, thus predominantly measuring monomeric CT and KT. The same protocol was repeated 14 days after surgery. Removal of the gonads in reproductive age did not alter basal or peak CT levels (9.7 +/- 0.8 vs. 8.9 +/- 0.7 ng/l and 13.4 +/- 1.6 vs. 12.7 +/- 1.2 ng/l) or KT levels (3.2 +/- 1.8 vs. 3.9 +/- 2.2 ng/l basal and 4.1 +/- 2.6 vs. 5.4 +/- 2.8 ng/l peak). Although not statistically different at any individual point, the shapes of the curves were significantly altered after surgery, indicating changes in the metabolism of CT and KT. These results support the hypothesis that CT and possibly KT play a role in the change of calcium metabolism coinciding with the oestrogen withdrawal at the menopause.