Response of epidermal polyamines to orally administered aromatic retinoid RO 10-9359.

Polyamine levels were measured in skin (pure epidermis) and 24-h urine before and 15 days after the start of continuous oral treatment with Etretinate (1 mg/kg/day) in 20 patients with various dermatoses. In uninvolved epidermis, treatment modified levels of spermidine (45% increase, P less than 0.05) and spermine (30% increase, P less than 0.05). In urine, the putrescine concentration was significantly altered, increasing from 1.96 to 2.60 micrograms/mg creat (P less than 0.05). During the time interval considered, variations in polyamine levels did not reflect the inhibiting mechanism of retinoids on ornithine decarboxylase, the key enzyme in the regulation of polyamine synthesis.