[Time of onset and regression of D-penicillamine activity, measured by rupture load of rat skin].

Two experiments were carried out to determine the period of time for a) the decrease of the load resulting in rupture of excised dorsal skin strips of the rat induced by daily oral treatment with D-beta, beta-dimethylcysteine (D-penicillamine, Metalcaptase) and b) the effect produced by D-penicillamine treatment to subside after discontinuation of the substance. 1. On the 5th day of treatment (320 mg/kg/day), the load resulting in rupture of excised dorsal skin strips of rats from an animal group decreased from 3480 p (initial value) to 2350 p. On the 9th day of treatment, the value for the load resulting in rupture dropped to 1790 p. Further decrease of the load resulting in rupture cannot be obtained even after a 2 weeks' treatment with 320 mg/kg D-penicillamine. 2. An animal group was treated with 320 mg/kg D-penicillamine for 7 days. At the end of this period of treatment, the load resulting in rupture of excised dorsal skin strips amounts to 1400 p. After discontinuation of the medication, the load resulting in rupture of the dorsal skin is determined at intervals of several days. 6 days after discontinuation of the test substance, a marked rise was observed and after 15 days, no difference was found between the initial value of non-treated animals and previously treated animals. Thus, it takes a few days only to induce a decrease of the load resulting in rupture by D-penicillamine and its recovery after discontinuing the medication.