title: Circadian variation of cyclic AMP in the rat pineal gland.
abstract: This study was carried out to investigate circadian variation of cyclic AMP contents in the rat pineal glands, using the high-energy microwave radiation technique. The pattern of cyclic AMP concentration in the pineal gland showed a distinct circadian variation, with the maximum level at 0200 and the lowest at 1400. The administration of propranolol completely blocked the dark-induced increase in the pineal cyclic AMP level at 0200, and the administration of isoproterenol induced a threefold, rapid increase in the cyclic AMP level at 1400, although it did not change the level at 0200.
mesh_terms: D000818:Animals; D002940:Circadian Rhythm / Q000187:drug effects; D000242:Cyclic AMP / Q000378:metabolism*; D007545:Isoproterenol / Q000494:pharmacology; D008297:Male; D010870:Pineal Gland / Q000187:drug effects / Q000378:metabolism*; D011433:Propranolol / Q000494:pharmacology; D051381:Rats
chemical_list: D011433:Propranolol; D000242:Cyclic AMP; D007545:Isoproterenol