Circadian cycles in VIP content and VIP stimulation of cyclic AMP accumulation in the rat pineal gland.
VIP content in the rat pineal gland and cyclic AMP accumulation in response to VIP in the daily light and dark cycle were examined. VIP content in the pineal varied significantly during the day and night; the content decreased during exposure to light and was lowest at the onset of darkness, 6 p.m. (mean +/- SE, 23 +/- 5 pg/pineal), and increased during the night and was highest at the onset of light, 6 a.m. (72 +/- 12 pg/pineal). Response of cyclic AMP accumulation to VIP varied with a periodicity inversely related to the daily light and dark cycle of VIP content; cyclic AMP accumulation in response to 10(-7) M VIP increased in proportion to periods of exposure to light and peaked at 6 p.m., and decreased with the onset of darkness.
D000818:Animals; D002940:Circadian Rhythm; D000242:Cyclic AMP / Q000378:metabolism*; D003624:Darkness; D008027:Light; D008297:Male; D010870:Pineal Gland / Q000187:drug effects / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains; D014660:Vasoactive Intestinal Peptide / Q000378:metabolism* / Q000494:pharmacology
D014660:Vasoactive Intestinal Peptide; D000242:Cyclic AMP