Cold-induced salt intake in mice and catecholamine, renin and thermogenesis mechanisms.
Cold induces increased intake of salt in mice. To examine involvement of renin and catecholamines, male ICR mice were exposed to cold (7-9 degrees C; 6 h/day; 4 days), and half of them were allowed to choose between water and 0.9% NaCl. Plasma renin activity (PRA) and catecholamine concentrations in plasma, adrenal gland, kidney, brown adipose tissue (BAT) and brain were examined in three phases: for 9 h before exposure to cold, during 6 h of cold exposure and for 9 h after the exposure. The amount of salt intake from NaCl solution and from food, PRA and noradrenaline (NE) concentrations in kidney and medulla oblongata were higher during cold and the 9 h after exposure to cold than during the 9 h before the exposure. These results are consistent with the suggestion that cold induced catecholamine metabolism enhanced activity in the renin-angiotensin system, which played an important role in the arousal of salt appetite. During cold exposure, concentrations of NE and dopamine in BAT were higher in mice with access to NaCl solution than those without NaCl to drink. These results suggest that cold-induced salt intake enhanced non-shivering thermogenesis, and are consistent with our previous report that high salt intake helped to maintain colonic temperature under cold exposure.
Dejima
Y
Y
Department of Human Ecology, Faculty of Health Sciences, Kyorin University, Tokyo, Japan.
Fukuda
S
S
Ichijoh
Y
Y
Takasaka
K
K
Ohtsuka
R
R
D002001:Adipose Tissue, Brown / Q000378:metabolism; D000311:Adrenal Glands / Q000378:metabolism; D000818:Animals; D001833:Body Temperature Regulation / Q000502:physiology*; D002395:Catecholamines / Q000097:blood / Q000378:metabolism*; D003080:Cold Temperature; D004298:Dopamine / Q000097:blood / Q000378:metabolism; D004326:Drinking; D004435:Eating; D004837:Epinephrine / Q000097:blood / Q000378:metabolism; D007031:Hypothalamus / Q000378:metabolism; D007668:Kidney / Q000378:metabolism; D008297:Male; D008526:Medulla Oblongata / Q000378:metabolism; D051379:Mice; D008813:Mice, Inbred ICR; D009638:Norepinephrine / Q000097:blood / Q000378:metabolism; D012083:Renin / Q000097:blood*; D017673:Sodium Chloride, Dietary / Q000008:administration & dosage*; D012982:Sodium, Dietary / Q000008:administration & dosage
D002395:Catecholamines; D017673:Sodium Chloride, Dietary; D012982:Sodium, Dietary; D012083:Renin; D004298:Dopamine; D009638:Norepinephrine; D004837:Epinephrine