[Diurnal rhythm of endogenous somatostatin in patients with carcinoid].

Aim Of The Study: Was to investigate the differences of the circadian rhythm of the endogenous somatostatin in patients with carcinoid and in healthy probands.

Methods: The group of 30 patients (16 men/14 women) was divided onto two groups. The group M of 20 (12/8) pts with metastatic disease and group B of 10 pts without known metastases at the time of investigation. The control group A included by 12 healthy probands (7/5). Plasma levels of somatostatin were determined by radioimmunoassay. Fisher periodogram and Halberg's cosinor were used for statistical evaluation.

Results: We confirmed the 24-hour circadian rhythm of somatostatin in group A, B and M. Patients of the M group when compared with A and B groups had higher mesor and the later 24-hour acrophase (p < 0.05) and 12-hour acrophase (p < 0.05). Treatment with lanreotide led to the significant decrease of the somatostatin mesor (p < 0.05).