Acute effects of two melanocytolytic agents, hydroquinone and beta-mercaptoethanolamine, upon tyrosinase activity and cyclic nucleotide levels in murine melanomas.

The acute in vitro actions of two potent melanocytolytic agents, hydroquinone (HQ) and beta-mercaptoethanolamine (MEA), were determined in the B-16, Cloudman S-91 and Harding-Passey (HP) murine melanomas grown in vivo. Drug treated melanoma dice (5--480 min) were analyzed for tyrosinase activity and cyclic nucleotide levels (cAMP, cGMP). HQ and MEA effects on tyrosinase activity are complex and vary with tumor type, duration of treatment and agent tested.

Survival of mice receiving melanoma transplants is promoted by hydroquinone.

In BALB/c female mice with melanoma transplants, the incidence of "takes" is decreased and survival is increased by hydroquinone, a melanocytolytic agent. The mechanism of drug action is suggested by via DNA. The significant and high degree of positive response to hydroquinone treatment in vivo is encouraging for the clinical management of melanoma with melanocytolytic agents.

Serum tyrosinase in malignant disease, its activity, and the electrophoretic patterns of the enzyme as carried by immunoglobulins'.

Serum tyrosinase activity in many persons with metastatic diseases was found to be significantly higher than activity in normal persons. The highest activity was observed in melanoma and breast carcinoma. The electrophoretic patterns of serum tyrosinase, resolved by electrophoresis of a serum tyrosinase fraction followed by incubation of the gel sample with L-dopa, and represented as sets of RF's of melanin bands, were characteristically different in melanoma, breast carcinoma, and certain other diseases.

Effect of ACTH and corticosterone on melanogenesis and cyclic nucleotide levels in the B-16 melanoma.

The acute in vitro action of ACTH and corticosterone individually and in combination were determined in the B-16 melanoma grown in vivo. ACTH elevated levels 10-fold while tyrosinase activity generally was depressed. Corticosterone depressed cAMP levels and tyrosinase activity.