AJP - Regulatory, Integrative and Comparative Physiology, Vol 253, Issue 4 580-R586, Copyright © 1987 by American Physiological Society
Protection against fat cell hyperplasia in a hibernator, Glis glis
N. Mrosovsky, P. Nash and I. M. Faust
Department of Zoology, University of Toronto, Ontario, Canada.
Dormice, Glis glis, were fed a high-fat diet for 11 mo in one experiment:
in another experiment they were fed a high-fat diet for 5 mo, either at
room temperature (21.5 degrees C) or in a warm room (27 degrees C). Only in
the latter group did adipocyte hyperplasia occur; this was significant in
all the fat depots studied (inguinal, retroperitoneal, and gonadal). In the
other groups there was no evidence of fat cell hyperplasia, despite weight
gains from approximately 160 g (peaks on chow diet) to approximately 250 g
(maximums on high-fat diet). Instead, fat cell size, assessed from biopsies
of the inguinal area, became considerably enlarged. Taken together with
earlier data from other species, the results suggest that hibernators are
protected against fat cell hyperplasia. In dormice this protection appears
to be present at all phases of their seasonal weight cycles. For species
that experience several cycles of weight gain and loss in their lives, it
may be adaptive to avoid increases in adipocyte number.
