Vasoactive intestinal peptide stimulates type II thyroxine 5'-deiodinase and N-acetyltransferase activities in dispersed pineal cells of euthyroid and hypothyroid rats.
The effect of vasoactive intestinal peptide (VIP) on thyroxine type II 5'-deiodinase (5'-D) and N-acetyltransferase (NAT) activities were studied using pineal cells of euthyroid and hypothyroid rats. VIP activated 5'-D activity in a dose-dependent manner in both euthyroid and hypothyroid animals. However, basal and VIP stimulated activity was higher in pinealocytes from hypothyroid than in cells from euthyroid rats. VIP was also able to stimulate NAT activity but hypothyroidism did not induce modifications in its activity. Both 5'-D and NAT activities were stimulated not only by VIP, but also by isoproterenol, a beta-adrenergic receptor agonist, and forskolin, a potent activator of adenylate cyclase activity. The results suggest that VIP may be involved in the physiological regulation of pineal 5'-D activity.
Department of Medical Biochemistry and Molecular Biology, University of Seville School of Medicine, Spain.
P
P
Molinero
J M
JM
Guerrero
D000818:Animals; D001191:Arylamine N-Acetyltransferase / Q000378:metabolism*; D005576:Colforsin / Q000494:pharmacology; D007037:Hypothyroidism / Q000201:enzymology*; D066298:In Vitro Techniques; D007453:Iodide Peroxidase / Q000378:metabolism*; D007457:Iodine Radioisotopes; D007545:Isoproterenol / Q000494:pharmacology; D010870:Pineal Gland / Q000187:drug effects / Q000201:enzymology*; D011433:Propranolol / Q000494:pharmacology; D051381:Rats; D014660:Vasoactive Intestinal Peptide / Q000494:pharmacology*
D007457:Iodine Radioisotopes; D005576:Colforsin; D014660:Vasoactive Intestinal Peptide; D011433:Propranolol; D007453:Iodide Peroxidase; D001191:Arylamine N-Acetyltransferase; D007545:Isoproterenol