Thermoregulatory responses to hyperinsulinemic hypoglycemia and euglycemia in humans.
Hypoglycemia induces physiological changes that influence thermoregulatory mechanisms. We studied such responses in a group of healthy males (mean age 23.5 yr, body mass index 23.7 kg/m2) during hyperinsulinemic euglycemia (E; 4.5 mmol/l) and hypoglycemia (H; 2.5 mmol/l) and under placebo control conditions (P; saline). Plasma epinephrine (P < 0.0001) and norepinephrine (P < 0.01) levels increased during H and were unchanged during P and E. During H, early increases in metabolic rate (P < 0.05), forearm blood flow (P < 0.01), and sweating (P < 0.01) were followed by a fall in skin temperature (from -1.2 to -2.6 degrees C) and blood flow (P < 0.01). Core temperature fell after 40 min of H and continued to fall thereafter (-0.34 +/- 0.08 degrees C). E and P had minimal effect on skin temperature and blood flow. In summary, in healthy human subjects, H causes a fall in core temperature by heat dissipation at the skin surface through evaporative heat loss and conduction of heat to the periphery, despite an increase in metabolic heat production.
Department of Physiology and Pharmacology, University of Nottingham, United Kingdom.
D G
DG
Maggs
A R
AR
Scott
I A
IA
MacDonald
D000328:Adult; D001786:Blood Glucose / Q000378:metabolism*; D001794:Blood Pressure; D001831:Body Temperature; D001833:Body Temperature Regulation; D003971:Diastole; D004837:Epinephrine / Q000097:blood; D005230:Fatty Acids, Nonesterified / Q000097:blood; D015309:Glucose Clamp Technique; D006339:Heart Rate; D006801:Humans; D006946:Hyperinsulinism / Q000503:physiopathology*; D007003:Hypoglycemia / Q000503:physiopathology*; D007328:Insulin / Q000097:blood*; D008297:Male; D009638:Norepinephrine / Q000097:blood; D012881:Skin Temperature; D013542:Sweat / Q000502:physiology; D013599:Systole; D013997:Time Factors
D001786:Blood Glucose; D005230:Fatty Acids, Nonesterified; D007328:Insulin; D009638:Norepinephrine; D004837:Epinephrine