Thyroid hormone and adrenergic signaling interact to control pineal expression of the dopamine receptor D4 gene (Drd4).
Dopamine plays diverse and important roles in vertebrate biology, impacting behavior and physiology through actions mediated by specific G-protein-coupled receptors, one of which is the dopamine receptor D4 (Drd4). Here we present studies on the >100-fold daily rhythm in rat pineal Drd4 expression. Our studies indicate that Drd4 is the dominant dopamine receptor gene expressed in the pineal gland. The gene is expressed in pinealocytes at levels which are approximately 100-fold greater than in other tissues, except the retina, in which transcript levels are similar. Pineal Drd4 expression is circadian in nature and under photoneural control. Whereas most rhythmically expressed genes in the pineal are controlled by adrenergic/cAMP signaling, Drd4 expression also requires thyroid hormone. This advance raises the questions of whether Drd4 expression is regulated by this mechanism in other systems and whether thyroid hormone controls expression of other genes in the pineal gland.
Kim
Jong-So
JS
Section on Neuroendocrinology, Program on Developmental Endocrinology and Genetics, National Institutes of Health, Bethesda, MD 20892, USA.
Bailey
Michael J
MJ
Weller
Joan L
JL
Sugden
David
D
Rath
Martin F
MF
Møller
Morten
M
Klein
David C
DC
D000318:Adrenergic beta-Agonists / Q000494:pharmacology; D000818:Animals; D002940:Circadian Rhythm / Q000502:physiology; D000242:Cyclic AMP / Q000378:metabolism; D004298:Dopamine / Q000378:metabolism; D007545:Isoproterenol / Q000494:pharmacology; D008297:Male; D009638:Norepinephrine / Q000378:metabolism*; D017440:Photoperiod; D010870:Pineal Gland / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D050638:Receptors, Dopamine D4 / Q000235:genetics / Q000378:metabolism; D012160:Retina / Q000166:cytology / Q000378:metabolism; D015398:Signal Transduction / Q000502:physiology*; D013963:Thyroid Hormones / Q000378:metabolism*; D014018:Tissue Distribution
D000318:Adrenergic beta-Agonists; C493601:Drd4 protein, rat; D013963:Thyroid Hormones; D050638:Receptors, Dopamine D4; D000242:Cyclic AMP; D007545:Isoproterenol; D004298:Dopamine; D009638:Norepinephrine