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Your search keyword '"Gonzalez-Brito A"' showing total 5 results
Start Over Author "Gonzalez-Brito A" Journal biochemical and biophysical research communications
5 results on '"Gonzalez-Brito A"'

1. N-acetyltransferase activity, hydroxyindole-O-methyltransferase activity, and melatonin levels in the Harderian glands of the female Syrian hamster: changes during the light:dark cycle and the effect of 6-parachlorophenylalanine administration

Author

Aldo Gonzalez-Brito, Russel J. Reiter, Kimberly A. Howes, and Armando Menendez-Pelaez

Subjects
Acetylserotonin O-Methyltransferase, endocrine system, medicine.medical_specialty, Light, Arylamine N-Acetyltransferase, Biophysics, Hamster, Biology, NAT activity, Biochemistry, N-acetyltransferase activity, Melatonin, Acetyltransferases, Internal medicine, Cricetinae, medicine, Animals, Molecular Biology, Syrian hamsters, Mesocricetus, Harderian Gland, Dark cycle, Fenclonine, Lacrimal Apparatus, Hydroxyindole O-methyltransferase activity, Cell Biology, Methyltransferases, Darkness, Circadian Rhythm, Endocrinology, Female, hormones, hormone substitutes, and hormone antagonists, medicine.drug
Abstract

The activities of NAT and HIOMT and the melatonin content of the Harderian glands of female Syrian hamsters were studied. When hamsters were kept under a light:dark cycle of 14:10 (lights on at 06.00 h), NAT activity exhibited a sharp, short term rise at one hour after lights on. Simultaneously, the activity of HIOMT, which forms melatonin, exhibited a rapid decline. Melatonin levels, like HIOMT activity, also showed a precipitous drop at one hour after light onset. After the respective changes, both NAT and HIOMT activity reverted back to night time levels. Melatonin levels remained depressed for several hours but by 1400 h (8 hours after lights on), nighttime melatonin values were re-established. Treatment of female hamsters with PCPA, a trytophan hydroxylase inhibitor, led to depressed levels of Harderian melatonin without affecting the activities of either NAT or HIOMT.

Published
1987

2. Forskolin, an activator of adenylate cyclase activity, promotes large increases in N-acetyl transferase activity and melatonin production in the Syrian hamster pineal gland only during the late dark period

Author

Aldo Gonzalez-Brito, C. Santana, Armando Menendez-Pelaez, Juan M. Guerrero, and Russel J. Reiter

Subjects
Male, endocrine system, medicine.medical_specialty, Arylamine N-Acetyltransferase, Biophysics, Hamster, Stimulation, Biology, Biochemistry, Pineal Gland, Melatonin, Pineal gland, chemistry.chemical_compound, Acetyltransferases, Internal medicine, Cricetinae, medicine, Animals, Molecular Biology, Forskolin, Mesocricetus, Activator (genetics), Colforsin, Cell Biology, Darkness, Circadian Rhythm, Enzyme Activation, medicine.anatomical_structure, Endocrinology, chemistry, Enzyme Induction, Serotonin, Cyclase activity, hormones, hormone substitutes, and hormone antagonists, medicine.drug, Adenylyl Cyclases
Abstract

Summary The exposure of organ cultured pineal glands of Syrian hamsters to forskolin, an adenylate cyclase activator, caused marked increases in serotonin N-acetyltransferase activity and melatonin content in a dose-related manner (1–100 μM) when glands were collected in the second half of the dark period. However, addition of forskolin to glands collected anytime during the light period or at the beginning of the dark period failed or only modestly stimulated either pineal N-acetyltransferase activity or melatonin levels. Similar results were obtained with isoproterenol. The results suggest that intrapinealocyte regulatory mechanisms may determine the nocturnal rise in the Syrian hamster pineal gland.

Published
1988

5. N-acetyltransferase activity, hydroxyindole-O-methyltransferase activity, and melatonin levels in the Harderian glands of the female Syrian hamster: changes during the light:dark cycle and the effect of 6-parachlorophenylalanine administration.

Author

Menendez-Pelaez A, Howes KA, Gonzalez-Brito A, and Reiter RJ

Subjects
Animals, Cricetinae, Darkness, Female, Harderian Gland drug effects, Harderian Gland radiation effects, Light, Mesocricetus, Acetylserotonin O-Methyltransferase metabolism, Acetyltransferases metabolism, Arylamine N-Acetyltransferase metabolism, Circadian Rhythm drug effects, Fenclonine pharmacology, Harderian Gland metabolism, Lacrimal Apparatus metabolism, Melatonin metabolism, Methyltransferases metabolism
Abstract

The activities of NAT and HIOMT and the melatonin content of the Harderian glands of female Syrian hamsters were studied. When hamsters were kept under a light:dark cycle of 14:10 (lights on at 06.00 h), NAT activity exhibited a sharp, short term rise at one hour after lights on. Simultaneously, the activity of HIOMT, which forms melatonin, exhibited a rapid decline. Melatonin levels, like HIOMT activity, also showed a precipitous drop at one hour after light onset. After the respective changes, both NAT and HIOMT activity reverted back to night time levels. Melatonin levels remained depressed for several hours but by 1400 h (8 hours after lights on), nighttime melatonin values were re-established. Treatment of female hamsters with PCPA, a trytophan hydroxylase inhibitor, led to depressed levels of Harderian melatonin without affecting the activities of either NAT or HIOMT.

Published
1987
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