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.
Maggs
D G
DG
Department of Physiology and Pharmacology, University of Nottingham, United Kingdom.
Scott
A R
AR
MacDonald
I A
IA
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