Gingival hyperplasia induced by calcium channel blockers: mode of action.

Gingival hyperplasia is a known side effect in patients treated with diphenylhydantoin, cyclosporin and the calcium channel antagonists. The present study proposes a mechanism by which calcium channel antagonists may induce gingival hyperplasia. The calcium antagonist induces blockage of the aldosterone synthesis in zona glomerulosa of the adrenal cortex since this pathway is calcium-dependent, cyclic nucleotide-independent. This may produce a feedback stimulation of an increase in pituitary secretion of ACTH which affects zona glomerulosa hyperplasia. This hyperplasia is merely related by accumulation of steroid intermediate products (androgens) that are transformed to testosterone because of an increase in 17-alpha-hydroxylase enzyme activity. Elevated levels of testosterone may act on the gingival cells and matrix to produce gingival hyperplasia.