Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:4.6.1.1 (adenylate cyclase)
 19,190 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The human promyelocytic cell line HL-60, differentiates in response to a variety of agents including dibutyryl cAMP and agents which increase intracellular cAMP concentrations (phosphodiesterase inhibitors, PGE2, and cholera toxin). HL-60 is also known to be rich in H2 -histamine sensitive adenylate cyclase activity. The present study was therefore designed to test the effects of H2-stimulation on growth and differentiation of HL-60 using the potent H2 agonist dimaprit. Dimaprit markedly increased cAMP production in a dose-dependent manner reaching maximal levels after 30-60 minutes. Intracellular cAMP levels decreased thereafter and by 24 hours were approximately 2-3 fold increased above control. Intracellular cAMP levels were not altered by dimaprit (10(-7)M to 10(-4)M) at 4 days in culture compared to either untreated HL-60 cells or dimethylsulfoxide (DMSO) (1.3%) treated cells. While exponential growth was unaltered by dimaprit (10(-7)M to 10(-4)M) as compared to control, dimaprit induced i) morphologic maturation to the myelocyte and metamyelocyte form with no differentiation seen beyond the metamyelocyte even after 6 days in culture, ii) increased NBT reductase activity and iii) dose-dependent increase in lysozyme activity which could be completely blocked by cimetidine, a specific H2 antagonist. Dimaprit-induced differentiation of HL-60 cells was associated with an initial but transient increase in intracellular cAMP production. Maturation beyond the metamyelocyte stage was not observed. Acquisition of NBT reductase and lysozyme activity correlated with morphologic maturation.
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PMID:Effects of dimaprit on growth and differentiation of human promyelocytic cell line, HL-60. 298 4

To examine the possibility of luteolin as a whitening agent, we measured antioxidant activity using DPPH assay, NBT/XO assay and intracellular ROS scavengning assay and depigmenting activity using tyrosinase assay, alpha-MSH-induced melanin production in B-16 cells. Luteolin showed dose-dependent anti-oxidant activity in DPPH, NBT/XO and intracellular ROS assay. Also, luteolin directly inhibited xanthine oxidase activity in a dose-dependent manner. Although luteolin did not directly inhibit tyrosinase activity, it dose-dependently inhibited both tyrosinase activity and melanin production in B16 melanoma cells stimulated by 1 microM alpha-MSH. Luteolin dose-dependently inhibited cAMP levels in B16 melanoma cells stimulated by 1 microM alpha-MSH and 1 microM forskolin, which suggest that luteolin directly inhibits adenyl cyclase in B16 melanoma cells. Therefore, these results suggest that whitening activity of luteolin may be due to the inhibition of adenyl cyclase involved in the signal pathway of alpha-MSH in B16 melanoma cells.
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PMID:Whitening activity of luteolin related to the inhibition of cAMP pathway in alpha-MSH-stimulated B16 melanoma cells. 1880 60