Diurnal variation in hepatic expression of the rat S14 gene is synchronized by the photoperiod

Journal Article · Wed Apr 01 04:00:00 EST 1987 · Endocrinology; (United States)

DOI:https://doi.org/10.1210/endo-120-4-1563· OSTI ID:6523756

Kinlaw, W B; Fish, L H; Schwartz, H L; Oppenheimer, J H

We have analyzed the factors responsible for the circadian variation in rat hepatic mRNA-S14. Regulation of this sequence, which is found in lipogenic tissues and encodes a protein (S14) believed to be associated with fatty acid synthesis, is an excellent model of the interaction of thyroid hormone and dietary factors at the hepatocellular level. The mRNA exhibits a 3-fold diurnal variation (peak, approximately 2000 h; nadir, 0800 h) in ad libitum feeding rats on a 12-h light, 12-h dark photoschedule. We studied the effects of the photoschedule, periodic food intake, hypophysectomy, and induction by thyroid hormone (T3) on the mRNA-S14 rhythm. Adaptation to feeding restricted to either light or dark periods for 15 days did not greatly affect the diurnal rhythm. Photoreversal resulted in a 180 degrees phase shift, whereas the rhythm persisted in the presence of constant light. Oscillation continued around a higher baseline after a receptor-saturating dose of T3 in both normal and hypophysectomized rats. Our results indicate primary entrainment of the mRNA-S14 diurnal rhythm to the photoperiod, rather than to periodic food intake. Moreover, the circadian regulatory signal, which probably originates in the central nervous system, appears capable of antagonizing a maximal T3-inductive stimulus and does not originate in the pituitary gland. Persistence of the oscillation in constant light rules out circulating melatonin as the mediator. Synchronization of the rhythm by the photoschedule suggests that neuroendocrine factors are important determinants of rhythmic changes in hepatic gene expression.

• Research Organization: Univ. of Minnesota, Minneapolis
• OSTI ID: 6523756
• Journal Information: Endocrinology; (United States), Journal Name: Endocrinology; (United States) Vol. 4; ISSN ENDOA
• Country of Publication: United States
• Language: English

Related Subjects

550400* -- Genetics
59 BASIC BIOLOGICAL SCIENCES
ANIMALS
BIOLOGICAL EFFECTS
BIOLOGICAL MODELS
BODY
DAILY VARIATIONS
DIET
DIGESTIVE SYSTEM
GENE REGULATION
GLANDS
HORMONES
HYPOPHYSECTOMY
LIVER
MAMMALS
MEDICINE
MESSENGER-RNA
NUCLEIC ACIDS
NUTRITION
ORGANIC COMPOUNDS
ORGANS
PEPTIDE HORMONES
PHOTOPERIOD
PROTEINS
RATS
RNA
RODENTS
SURGERY
THYROID HORMONES
TRIIODOTHYRONINE
VARIATIONS
VERTEBRATES