title: Hypothalamic growth hormone-releasing hormone mRNA varies across the day in rats.
abstract: Experiments were performed to determine whether growth hormone-releasing hormone (GHRH) mRNA displays diurnal variations in the hypothalamus and cortex of the rat. Levels of GHRH and beta-actin mRNA were measured from hypothalamic and cortical extracts using the reverse transcriptase polymerase chain reaction method in rats sacrificed at 4 h intervals across a 12:12 h light:dark cycle. Hypothalamic GHRH mRNA peaked around the light onset, declined during the light period, and stayed low in the dark. Variations in hypothalamic beta-actin and cortical GHRH mRNA levels were not observed. beta-Actin mRNA expression in the cortex was higher in the dark than in the light period. The results demonstrate that hypothalamic GHRH mRNA displays diurnal variations.
authors.affiliation: Department of Physiology and Biophysics, University of Tennessee, Memphis 38163, USA.
authors.forename: S
authors.initials: S
authors.lastname: Bredow
authors.forename: P
authors.initials: P
authors.lastname: Taishi
authors.forename: F
authors.initials: F
authors.lastname: Obél
authors.forename: N
authors.initials: N
authors.lastname: Guha-Thakurta
authors.forename: J M
authors.initials: JM
authors.lastname: Krueger
mesh_terms: D000818:Animals; D002540:Cerebral Cortex / Q000378:metabolism*; D002940:Circadian Rhythm / Q000502:physiology*; D013007:Growth Hormone-Releasing Hormone / Q000378:metabolism*; D007031:Hypothalamus / Q000378:metabolism*; D008297:Male; D016133:Polymerase Chain Reaction; D051381:Rats; D017207:Rats, Sprague-Dawley
chemical_list: D013007:Growth Hormone-Releasing Hormone