title: Diurnal changes in cyclic nucleotide response to pineal indoles in murine mammary glands.
abstract: The aim of this study was to determine whether pineal indoles affect cyclic nucleotide levels in mammary gland slices of BALB/c adult mice. Melatonin at 0.1 nM-10 microM concentrations decreased cAMP and augmented cGMP concentration in murine mammary gland slices in the presence of a phosphodiesterase inhibitor (1 mM theophylline), an index of cyclic nucleotide synthesis. Melatonin-induced changes in cyclic nucleotide levels were significantly larger at the end of the light period (2000) than in the morning (at 1000). Indole-induced inhibition of cyclic AMP levels by mammary slices exhibited the following order of potency: 5-methoxytryptamine > melatonin > or = 6-hydroxymelatonin > serotonin, N-acetylserotonin > 5-hydroxytryptophol. The order of potency for indole-induced augmentation of cyclic GMP levels was: 5-methoxytryptamine > melatonin > 6-hydroxymelatonin > serotonin, N-acetylserotonin, 5-hydroxytryptophol. When melatonin or 5-methoxytryptamine (10 nM) were examined for their effects on cAMP and cGMP levels in mammary glands of mice killed at six different time intervals during the 24-hr cycle, the activity was maximal during night. The data demonstrate that 5-methoxytryptamine and melatonin decreased cAMP and increased cGMP levels in mammary gland slices. Methoxyindole-induced changes in cyclic nucleotide synthesis in murine mammary glands exhibit the time-dependency known to occur in several other melatonin-influenced responses.
authors.affiliation: Departamento de Fisiología, Facultad de Mediciña, Universidad de Buenos Aires, Argentina.
authors.forename: D P
authors.initials: DP
authors.lastname: Cardinali
authors.forename: R A
authors.initials: RA
authors.lastname: Bonanni Rey
authors.forename: M D
authors.initials: MD
authors.lastname: Mediavilla
authors.forename: E
authors.initials: E
authors.lastname: Sánchez-Barceló
mesh_terms: D000818:Animals; D002940:Circadian Rhythm / Q000187:drug effects*; D000242:Cyclic AMP / Q000378:metabolism*; D006152:Cyclic GMP / Q000378:metabolism*; D005260:Female; D007211:Indoles / Q000494:pharmacology*; D008321:Mammary Glands, Animal / Q000187:drug effects* / Q000378:metabolism*; D051379:Mice; D008807:Mice, Inbred BALB C; D010870:Pineal Gland / Q000737:chemistry; D011863:Radioimmunoassay
chemical_list: D007211:Indoles; D000242:Cyclic AMP; D006152:Cyclic GMP