title: Impairment of heme biosynthesis induces short circadian period in body temperature rhythms in mice.
abstract: It has been demonstrated that the function of mammalian clock gene transcripts is controlled by the binding of heme in vitro. To examine the effects of heme on biological rhythms in vivo, we measured locomotor activity (LA) and core body temperature (T(b)) in a mouse model of porphyria with impaired heme biosynthesis by feeding mice a griseofulvin (GF)-containing diet. Mice fed with a 2.0% GF-containing diet (GF2.0) transiently exhibited phase advance or phase advance-like phenomenon by 1-3 h in terms of the biological rhythms of T(b) or LA, respectively (both, P < 0.05) while mice were kept under conditions of a light/dark cycle (12 h:12 h). We also observed a transient, ~0.3 h shortening of the period of circadian T(b) rhythms in mice kept under conditions of constant darkness (P < 0.01). Interestingly, the observed duration of abnormal circadian rhythms in GF2.0 mice lasted between 1 and 3 wk after the onset of GF ingestion; this finding correlated well with the extent of impairment of heme biosynthesis. When we examined the effects of therapeutic agents for acute porphyria, heme, and hypertonic glucose on the pathological status of GF2.0 mice, it was found that the intraperitoneal administration of heme (10 mg·kg(-1)·day(-1)) or glucose (9 g·kg(-1)·day(-1)) for 7 days partially reversed (50%) increases in urinary δ-aminolevulinic acids levels associated with acute porphyria. Treatment with heme, but not with glucose, suppressed the phase advance (-like phenomenon) in the diurnal rhythms (P < 0.05) and restored the decrease of heme (P < 0.01) in GF2.0 mice. These results suggest that impairments of heme biosynthesis, in particular a decrease in heme, may affect phase and period of circadian rhythms in animals.
authors.affiliation: Department of Pharmaceutical Sciences, Faculty of Pharmacy, Keio University, Tokyo, Japan.
authors.forename: Reiko
authors.initials: R
authors.lastname: Iwadate
authors.forename: Yoko
authors.initials: Y
authors.lastname: Satoh
authors.forename: Yukino
authors.initials: Y
authors.lastname: Watanabe
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Kawai
authors.forename: Naomi
authors.initials: N
authors.lastname: Kudo
authors.forename: Yoichi
authors.initials: Y
authors.lastname: Kawashima
authors.forename: Tadahiko
authors.initials: T
authors.lastname: Mashino
authors.forename: Atsushi
authors.initials: A
authors.lastname: Mitsumoto
mesh_terms: D000818:Animals; D001831:Body Temperature / Q000187:drug effects / Q000502:physiology*; D002940:Circadian Rhythm / Q000187:drug effects / Q000502:physiology*; D004195:Disease Models, Animal; D005947:Glucose / Q000494:pharmacology; D006118:Griseofulvin / Q000009:adverse effects / Q000494:pharmacology; D006418:Heme / Q000378:metabolism* / Q000494:pharmacology; D008124:Locomotion / Q000187:drug effects / Q000502:physiology; D008297:Male; D051379:Mice; D008813:Mice, Inbred ICR; D011164:Porphyrias / Q000139:chemically induced / Q000378:metabolism* / Q000503:physiopathology
chemical_list: D006118:Griseofulvin; D006418:Heme; D005947:Glucose