In vivo activation of pineal N-acetyltransferase but not type II thyroxine 5'-deiodinase by phenylephrine in young rats.
The regulation by alpha- and beta-adrenergic agonists of pineal N-acetyltransferase (NAT) and type II thyroxine 5'-deiodinase (5'-D) in rats at either 2 or 6 weeks of age was studied. The pattern of stimulation was different because NAT activity could be clearly activated by an alpha-adrenergic agonist, phenylephrine, only in 2-week-old rats. However, isoproterenol, a beta-adrenergic agonist, was able to stimulate NAT activity in rats at both 2 and 6 weeks of life. On the other hand, phenylephrine was always ineffective in stimulating 5'-D activity, while isoproterenol clearly activated it at both ages. These results strongly suggest a role for alpha-adrenergic receptors, in addition to beta-adrenergic receptors, in regulating rat pineal NAT activity during development.
University of Seville School of Medicine, Department of Medical Biochemistry and Molecular Biology, Spain.
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A
Rubio
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C
Osuna
J
J
Jiménez
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Molinero
J M
JM
Guerrero
D000316:Adrenergic alpha-Agonists / Q000494:pharmacology; D000318:Adrenergic beta-Agonists / Q000494:pharmacology; D000818:Animals; D001191:Arylamine N-Acetyltransferase / Q000378:metabolism*; D005260:Female; D007453:Iodide Peroxidase / Q000378:metabolism*; D007545:Isoproterenol / Q000494:pharmacology; D008297:Male; D010656:Phenylephrine / Q000494:pharmacology*; D010870:Pineal Gland / Q000201:enzymology*; D051381:Rats; D011919:Rats, Inbred Strains
D000316:Adrenergic alpha-Agonists; D000318:Adrenergic beta-Agonists; D010656:Phenylephrine; D007453:Iodide Peroxidase; D001191:Arylamine N-Acetyltransferase; D007545:Isoproterenol