Henry Ford Hospital Medical Journal


A tissue culture explant and a primary cell culture of malignant C-cells have been estabUshed to study the secretion pattern of calcitonin (CT), katacalcin (KC), and CT gene-related peptide (CGRP) in vitro under different conditions. Within the first five days of culture the spontaneous secretion of the peptides in both systems dropped to and remained at a constant level. With increasing calcium (Ca) concentration in the medium, a dose dependent release of CT, KC and, in cell culture, of CGRP was observed. BAY-K-8644. an analog of the Ca channel blocker nifedipine, enhanced the CT secretion to the same extent as Ca in a concentration of 10−4M in tissue, and of 10−5M in cell culture. This stimulation effect of BAY-K-8644 could be inhibited by an equimolar amount of nifedipine. Medullary thyroid carcinoma tissue explants as well as primary cell culture are therefore reliable models for studying the secretion pattern of peptides of the CT family. The effect of BAY-K-8644 and nifedipine suggests a physiological role of Ca channels in stimulus-secretion coupling.