Sherpa brain glucose metabolism and defense adaptations against
chronic hypoxia.
Hochachka, P. W., C. M. Clark, C. Monge, C. Stanley, W. D. Brown, C.
K. Stone, R. J. Nickles, and J. E. Holden.
Dept. of Zoology and Sports Medicine Division, University of
British Columbia, Vancouver, B.C. V6T 1Z4; Dept. of Psychiatry,
University of British Columbia, Vancouver, B.C.; Dept. of Physiology,
Cayetano Heredia University, Lima, Peru; Dept. of Medical Physics,
Radiology, and Medicine, Univ. of Wisconsin, Madison, WI 53706
APStracts 3:0203A, 1996.
The brain of hypoxia tolerant vertebrates is known to survive extreme
oxygen limitation at least in part because of very low rates of ATP
utilization and of ATP production. To assess if similar adaptations
are involved in healthy humans during hypoxia adaptations over
generational time, we initially used positron emission tomography
(PET) measurements of glucose metabolic rates in the brain of
Quechuas, whose ancestors have been indigenous to the Andes between
about 3300 and 4500 m for several hundred years. Workers in this
field generally believe that the lineage of Sherpas has been
indigenous to the Himalayas for even longer and that Sherpas and
other peoples indigenous to the Tibetan plateau are perhaps most
exquisitely hypoxia adapted of all humans. For this reason, in this
study we extended our data base to include Sherpas. Using the same
protocols as before, two metabolic states were analyzed: (a) the
presumed normal (hypoxia adapted) state monitored as soon as possible
after leaving the Himalayas, and (b) the deacclimated state monitored
after 3 weeks at low altitudes. PET measurements of[18F]-2-deoxy-2
-fluro-D-glucose (FDG) metabolic rates, quantified in 26 regions of
the brain, indicated that the Sherpa brain metabolism differed
significantly from that of Quechuas but was essentially identical to
that of lowlanders. Region-by-region patterns were similar in all
three groups indicating that the regional organization of glucose
metabolism in the brain is a conservative, relatively constant
characteristic.
Received 30 November 1995; accepted in final form 8 April 1996.
APS Manuscript Number A1237-5.
Article publication pending Journal of Applied Physiology.
ISSN 1080-4757 Copyright 1996 The American Physiological Society.
Published in APStracts on 23 April 96