The role of dehydroepiandrosterone levels on physiologic acclimatization to chronic mountaineering activity.
Previous studies have reported that glucose tolerance can be improved by short-term altitude living and activity. However, not all literature agrees that insulin sensitivity is increased at altitude. The present study investigated the effect of a 25-day mountaineering activity on glucose tolerance and its relation to serum levels of dehydroepiandrosterone-sulfate (DHEA-S) and tumor necrosis factor-alpha (TNF-alpha) in 12 male subjects. On day 3 at altitude, we found that serum DHEAS was reduced in the subjects with initially greater DHEA-S value, whereas the subjects with initially lower DHEA-S remained unchanged. To further elucidate the role of DHEA-S in acclimatization to mountaineering activity, all subjects were then divided into lower and upper halves according to their sea-level DHEA-S concentrations: low DHEA-S (n = 6) and high DHEA-S groups (n = 6). Glucose tolerance, insulin level, and the normal physiologic responses to altitude exposure, including hematocrit, hemoglobin, erythropoietin (EPO), and cortisol were measured. We found that glucose and insulin concentrations on an oral glucose tolerance test were significantly lowered by the mountaineering activity only in the high DHEA-S group. Similarly, hematocrit and hemoglobin concentration in altitude were increased only in the high DHEA-S group. In contrast, the low DHEA-S subjects exhibited an EPO value at sea level and altitude greater than the high DHEA-S group, suggesting an EPO resistance. The findings of the study imply that DHEA-S is essential for physiologic acclimatization to mountaineering challenge.
Lee
Wen-Chih
WC
Committee of General Studies, Shih Hsin University, Taipei, Taiwan, ROC.
Chen
Shu-Man
SM
Wu
Min-Chieh
MC
Hou
Chien-Wen
CW
Lai
Yu-Chiang
YC
Laio
Yi-Hung
YH
Lin
Chin-Hung
CH
Kuo
Chia-Hua
CH
D000064:Acclimatization / Q000502:physiology*; D000328:Adult; D003687:Dehydroepiandrosterone / Q000097:blood*; D004921:Erythropoietin / Q000097:blood; D005951:Glucose Tolerance Test; D006403:Hematologic Tests; D006801:Humans; D006854:Hydrocortisone / Q000097:blood; D007328:Insulin / Q000097:blood; D007333:Insulin Resistance / Q000502:physiology; D008297:Male; D009051:Mountaineering / Q000502:physiology*; D010101:Oxygen Consumption; D014409:Tumor Necrosis Factor-alpha / Q000097:blood
D007328:Insulin; D014409:Tumor Necrosis Factor-alpha; D004921:Erythropoietin; D003687:Dehydroepiandrosterone; D006854:Hydrocortisone