Thermoregulatory responses to hyperinsulinaemic hypoglycaemia and euglycaemia in IDDM.
In healthy subjects hypoglycaemia causes a fall in body temperature through increased sweating and limb blood flow, and despite increased metabolic heat production. We studied thermoregulatory responses to hyperinsulinaemic (100 mU.m-2.min-1) (a) hypoglycaemia (2.5 mmol/l) and (b) euglycaemia (4.5 mmol/l) in insulin-dependent diabetic men of short (< 5 years) and long (> 15 years) diabetes duration. Plasma noradrenaline (p < 0.0001), metabolic rate (p < 0.005), heart rate (p < 0.0001) and skin blood flow (p < 0.05) increased during hypoglycaemia and euglycaemia with a greater rise in noradrenaline during the former (p < 0.05). Plasma adrenaline (p < 0.005), forearm blood flow (p < 0.05) and systolic blood pressure (p < 0.02) increased and diastolic blood pressure decreased (p < 0.005) during hypoglycaemia, with greater changes in adrenaline (p < 0.05) and diastolic blood pressure in patients of short diabetes duration. Only two patients (diabetes duration < 2 years) sweated appropriately, while body temperature changed minimally in the two groups of patients. In summary, thermoregulatory responses to hypoglycaemia are impaired in IDDM due to attenuated sweating and adrenomedullary responses.
Department of Physiology and Pharmacology, University of Nottingham, UK.
D G
DG
Maggs
I A
IA
Macdonald
R B
RB
Tattersall
D000328:Adult; D001341:Autonomic Nervous System / Q000502:physiology; D001786:Blood Glucose / Q000378:metabolism; D001794:Blood Pressure / Q000502:physiology; D001833:Body Temperature Regulation / Q000502:physiology*; D003922:Diabetes Mellitus, Type 1 / Q000097:blood / Q000503:physiopathology*; D004837:Epinephrine / Q000097:blood; D015309:Glucose Clamp Technique; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D006946:Hyperinsulinism / Q000097:blood / Q000503:physiopathology*; D007003:Hypoglycemia / Q000097:blood / Q000503:physiopathology*; D008297:Male; D009638:Norepinephrine / Q000097:blood
D001786:Blood Glucose; D009638:Norepinephrine; D004837:Epinephrine