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.

In vitro effects of theophylline and aminogluthetimide upon basal and ACTH induced cAMP levels and steroid output by the normal human adrenal gland.

The in vitro effects of theophylline and aminogluthetimide upon basal and ACTH stimulated cAMP, cortisol and aldosterone responses of normal human adrenocortical tissue were evaluated. Theophylline increased basal cAMP levels and cortisol output, however, basal aldosterone output was depressed. Theophylline in concert with ACTH depressed cortisol and aldosterone output.

Interaction of ACTH, corticosterone and cyclic nucleotides in Harding-Passey melanoma melanogenesis.

The acute in vitro action of adrenocorticotropin (ACTH) and corticosterone alone and in combination were determined in the Harding-Passey (HP) melanoma grown in vivo. Hormone treated melanoma dice (5--240 min) were analyzed for tyrosinase activity, cyclic AMP (cAMP) and cyclic GMP (cGMP). ACTH elevated cAMP and cGMP levels 20- and 13-fold, respectively, in the HP melanoma.

In vitro effects of melanocytolytic agents and other compounds upon dominant human melanoma tyrosinase activity.

The activity of dominant human melanoma tyrosinase isozyme was greatly decreased by certain reducing agents. The number and geometry of phenolic groups as well as free--SH group appear important for enzymic inhibition.

Serum thyrosinase in human lung carcinoma.

Compared to normal humans, lung carcinoma patients show increased tyrosinase activity. 7 serum enzymic fractions or carriers were present in the diseased state. Further, serum tyrosinase inhibitory factors generally were decreased in lung carcinoma patients compared to normal individuals.

Glucocorticoid modulation of adrenocorticotropin-induced melanogenesis in the Cloudman S-91 melanoma in vitro.

The acute in vitro action of adrenocorticotropin (ACTH) and corticosterone alone and in combination were determined in the Cloudman S-91 melanoma grown in vivo. Hormone-treated melanoma dice (5-240 min) were analyzed for tyrosinase activity (EC 1.14.

In vitro responses of focal hyperplastic tissue of the human adrenal zona fasciculata to ACTH.

The temporal cAMP, cortisol and aldosterone responses to ACTH of focal hyperplasia of the zona fasciculata and of normal human adrenocortical tissue were investigated. ACTH significantly increased cAMP levels (1 min) and cortisol output (2 min) in normal adrenal tissue but not in hyperplastic tissue. However, following ACTH treatment cortisol and aldosterone production were depressed in the abnormal adrenal tissue below the untreated or the ACTH stimulated normal adrenal tissue.

Trysinase positive oculocutaneous albinism in the goldfish, Carassius auratus l., and ultrastructural and biochemical study of the eye.

Ultrastructural studies, and cytochemical and biochemical determinations of tyrosinase activity were conducted on the pigment epithelium of albino and xanthic goldfish eyes. In eyes of xanthic goldfish, two types of melanosomes are present, spherical and elongated. Melanized melanosomes are absent in the eyes of the albino goldfish, but elongated lamellar premelanosomes are observed.

In vitro temporal cAMP and cortisol responses to ACTH by the normal human adrenal gland.

The in vitro temporal cAMP and cortisol responses of normal human adrenocortical tissue to ACTH were evaluated. ACTH stimulated rapid increased in cAMP levels and cortisol output, however, significantly increased cAMP levels preceded output only at the higher ACTH doses studied. Cortisol output plateaued with ACTH (10--100 MIU/ml) while cAMP levels continued to increase.

Mitochondrial redox components of human adrenocortical steroid hydroxylases under physiological conditions and in focal hyperplasia of the zone fasciculata.

Cytochrome P450, aa3 and adrenodoxin were characterized in human adrenocortical mitochondria. Human adrenodoxin demonstrated a distinctive electron paramagnetic spectrum exhibiting anisotropic g values indicative of axial symmetry. The observed g values were (formula: see text).