SALMON-CALCITONIN TREATMENT BY NASAL SPRAY IN PRIMARY HYPERPARATHYROIDISM

The hypocalcemic and hypophosphatemic effect of salmon calcitonin (sCT) given by intranasal (i.n.) spray to 12 patients with histological confirmed primary hyperparathyroidism (1-degrees-HPT) was studied. The concentration of ionized calcium in whole blood (B-Ca++), serum phosphate (S-P), magnesium (S-Mg), plasma sCT (Pl-sCT), and endogenous CT (hCT) was followed during five 24-hour periods with at least three days between. After period I (control day), 100 IU sCT was given intramuscularly (i.m.) in period II. In periods III-V, either 110, 200, or 400 IU of sCT were given intranasally (i.n.) in randomized order. Although B-Ca++ decreased from the baseline value with all four sCT treatments and at 4.5 hour on the control day (p < 0.05-0.001), the i.n. sCT treatments had no significant hypocalcemic effect, as the change of the area under the B-Ca++ curve (DELTA-AUC B-Ca++) for the three i.n. treatments was not significantly different from the control period (p < 0.001, ANOVA). Only the i.m. injection of calcitonin had a calcium-lowering effect (p < 0.001, ANOVA). Three subjects were considered nonresponders with a decrease in B-Ca++ less than 0.06 mmol/L. S-P decreased within three hours after 200 IU sCT i.n. and 100 IU i.m., but the S-Mg levels showed no consistent changes. The area under the curve for the Pl-sCT levels did not correlate with DELTA-AUC B-Ca++ except for i.m. given sCT. The endogenous hCT levels were undetectable in almost all patients despite a sensitive RIA for hCT, and did not increase during sCT treatment. Plasma levels of "intact" PTH-(1-84) increased significantly after 400 IU sCT i.n. at 3 and 6 hours. The local tolerance for the i.n. spray was good and no adverse effects were seen. In conclusion, intranasal sCT treatment (110, 200, or 400 IU) had no significant hypocalcemic effect on B-Ca++. However, S-P decreased after 200 IU i.n. and the PTH levels increased after 400 IU i.n., indicating some biologic effects of i.n. sCT in 1-degrees-HPT patients.