Nyctohemeral rhythmicity of type II thyroxine 5'-deiodinase activity in the pineal gland but not in the Harderian gland of the Swiss mouse.
Type II thyroxine 5'-deiodinase (5'-D) activity in both pineal and Harderian glands of the Swiss mouse was studied. Pineal 5'-D activity exhibited a nyctohemeral profile with a maximal peak value at 05.00 h, which coincides with that for pineal melatonin production. However, no rhythm of 5'-D activity in the Harderian gland could be found. In pineal gland, light at night inhibited the nocturnal increase in 5'-D activity, while isoproterenol, a beta-adrenergic agonist, could not stimulate the enzyme. In the Harderian gland, neither darkness, nor light or night, or isoproterenol were capable of modifying basal values of 5'-D activity.
Rubio
A
A
University of Seville School of Medicine, Department of Medical Biochemistry and Molecular Biology, Spain.
Osuna
C
C
Lopez-Gonzalez
M A
MA
Reiter
R J
RJ
Guerrero
J M
JM
D000818:Animals; D002940:Circadian Rhythm; D003624:Darkness; D006243:Harderian Gland / Q000201:enzymology* / Q000378:metabolism; D007453:Iodide Peroxidase / Q000378:metabolism*; D007545:Isoproterenol / Q000494:pharmacology; D008027:Light; D008297:Male; D008550:Melatonin / Q000378:metabolism; D051379:Mice; D010870:Pineal Gland / Q000201:enzymology* / Q000378:metabolism
D007453:Iodide Peroxidase; D008550:Melatonin; D007545:Isoproterenol