Endocrine Abstracts

Objectives: The aim of the study was to compare serum calcitonin levels after calcium versus pentagastrin stimulation in healthy individuals and in patients with medullary thyroid carcinoma (MTC).

Methods: The study enrolled 44 healthy individuals and 27 patients with MTC.

Time of measurement: baseline, 2, 5 and 10 min after injection of:

– Calcium 2.0 mg/kg body mass i.v. (10% Calcium Gluconate, Braun Melsungen AG, Germany). Injection speed 10 ml/min.

– Pentagastrin 0.5 μg/kg body mass i.v. (Pentagastrin Injection BP, Cambridge

Laboratories, Wallsend, UK). Injection speed 10 s.

After calcium stimulation there was a washout period of at least two weeks before the pentagastrin stimulation.

Calcitonin assay: solid phase chemiluminescent enzyme immunoassay (IMMULITE 2000, Siemens Healthcare Diagnostics).

Results: Mean calcitonin levels (pg/ml) in healthy individuals after calcium injection: 1.2/19.5*/16.4*/10.2*. After pentagstrin injection: 1.3/4.5/4.0/2.4 (*P<0.05). Nonresponse rate after calcium stimulation 18.2%, after pentagastrin stimulation 56.7%. Mean peak calcitonin levels in each group were significantly different between men and females (after calcium: 53.7* vs 11.8 / after pentagastrin: 18.3* vs 1.8 (*P<0,05)).

Mean calcitonin levels (pg/ml) in MTC patients after calcium injection: 113/1557/1467/1397. After pentagastrin injection: 114/3549/3252/2053 (n.s.). Mean peak values of calcitonin in each group between men and females were not significantly different.

Conclusions: The calcium stimulation is more sensitive than the pentagastrin stimulation in healthy individuals. In untreated or non-cured MTC patients the calcium stimulation is not inferior the pentagastrin stimulation. Moreover we suppose an earlier detection of MTC recurrence by calcium stimulation than by pentagastrin stimulation.