Hepatic portal injection of glucose elevates efferent sympathetic discharges of interscapular brown adipose tissue.
Efferent sympathetic discharges of interscapular brown adipose tissue were recorded after three different concentrations of glucose (138, 277, and 416 mM) and 154 mM NaCl were injected into the portal vein or into the right jugular vein. When injected into the portal vein there was a significant increase in the discharge in response to both concentrations of glucose (277 and 416 mM), whereas only 416 mM glucose solution could cause an increase in the discharge when injected into the right jugular vein. There was no appreciable change in the discharge following the NaCl injections into the portal and jugular veins, and the portal glucose responses in the discharge were abolished by transection of the hepatic branch of the vagus nerve. Since stimulated sympathetic activity has been shown to elevate thermogenesis of the adipose tissue, these findings suggest that vagal glucose signals derived from the portal vein may be involved in the regulation of heat production of this tissue.
Department of Physiology, Niigata University School of Medicine, Japan.
T
T
Sakaguchi
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M
Yamazaki
D002001:Adipose Tissue, Brown / Q000502:physiology*; D000818:Animals; D001831:Body Temperature; D005947:Glucose / Q000008:administration & dosage*; D007262:Infusions, Intravenous; D007601:Jugular Veins; D008297:Male; D009476:Neurons, Efferent / Q000502:physiology; D011169:Portal Vein; D051381:Rats; D011919:Rats, Inbred Strains; D012540:Scapula / Q000294:innervation*; D013564:Sympathetic Nervous System / Q000502:physiology*
D005947:Glucose