Journal of Lipid Research, Vol 23, 887-892, Copyright © 1982 by Lipid Research, Inc.
Adipose tissue cellularity in woodchucks: effects of season and captivity at an early age
RA Young, LB Salans and EA Sims
The objectives of this study were to determine the roles of adipocyte
hypertrophy and hyperplasia in the prehibernatory weight gain of adult
woodchucks and in the increased body weight of woodchucks born in
captivity. The seasonal increase in weight in wild adult woodchucks was
associated with an increase approaching tenfold in both body fat and in
subcutaneous and retroperitoneal adipocyte size. There was no increase in
total adipocyte number. Four groups of woodchucks were used in the study of
the effect of captivity: I) animals born to females bred in the laboratory;
II) those born to females captured just before parturition; III) those
captured at weaning; and IV) animals captured at 12 months of age. At 14
months non-fat body weight and subcutaneous adipocyte size were equal in
the four groups. The males but not the females in Groups I, II, and III had
both an increased body fat content and a significantly increased total
adipocyte number in comparison to the males in Group IV and the adults in
the seasonal study. This study demonstrates that captivity at an early age,
unlike prehibernatory weight gain, is associated with an increased
adipocyte number in male woodchucks, and this increase can occur after
weaning.