title: Twenty-four hour variation of alpha 1-adrenergic receptors in the pineal gland of the male Syrian hamster.
abstract: Specific binding of [125I]iodo-[beta-(4-hydroxyphenyl)-ethylaminomethyl]tetralone ([ 125I]HEAT) was used to assess alpha 1-adrenergic receptors on pineal gland membranes of male Syrian hamsters (Mesocricetus auratus) housed under a 14:10 h light-dark cycle (lights on at 06.00 h). Saturation experiments with pooled pineal membrane preparations showed the presence of alpha 1-adrenergic receptor sites (dissociation constant Kd approx. 0.1 nM). Analysis of 4 time points indicated no significant change in Kd, but significant (P less than 0.01) changes of receptor density (Bmax) with a minimum recorded at night. Binding of a constant amount of [125I]HEAT (200 pM) to pineal membranes at 8 time points exhibited a circadian variation (P less than 0.001) of receptor density with lowest values around midnight and highest levels during daytime.
authors.affiliation: Department of Cellular and Structural Biology, University of Texas Health Science Center, San Antonio 78284.
authors.forename: A
authors.initials: A
authors.lastname: Pangerl
authors.forename: B
authors.initials: B
authors.lastname: Pangerl
authors.forename: R J
authors.initials: RJ
authors.lastname: Reiter
authors.forename: G M
authors.initials: GM
authors.lastname: Vaughan
authors.forename: D J
authors.initials: DJ
authors.lastname: Jones
mesh_terms: D000317:Adrenergic alpha-Antagonists / Q000378:metabolism; D000818:Animals; D002940:Circadian Rhythm; D006224:Cricetinae / Q000378:metabolism*; D008297:Male; D008647:Mesocricetus / Q000378:metabolism* / Q000502:physiology; D010627:Phenethylamines / Q000378:metabolism; D010870:Pineal Gland / Q000378:metabolism* / Q000502:physiology; D011942:Receptors, Adrenergic, alpha / Q000378:metabolism / Q000502:physiology*; D044024:Tetralones
chemical_list: D000317:Adrenergic alpha-Antagonists; D010627:Phenethylamines; D011942:Receptors, Adrenergic, alpha; D044024:Tetralones; C010652:BE 2254