Consequences of weight cycling in obese spontaneously hypertensive
rats.
Ernsberger, Paul, Richard J. Koletsky, Jon S. Baskin, Laura A.
Collins.
Department of Medicine, Case Western Reserve School of Medicine,
St. Luke's Medical Center, 10900 Euclid Ave., Cleveland, OH 44106
-4982
APStracts 2:0302R, 1995.
We mimicked human weight cycling in the obese spontaneously
hypertensive rat (SHROB) model of genetic obesity. A 12d very low
calorie diet (VLCD; 16.7% of baseline calories) was alternated with
4-6 weeks of ad lib chow refeeding for 3 cycles. Control SHROB ate
chow ad lib. VLCD induced rapid weight loss, but during refeeding all
the lost weight was regained. Final body weight was higher in cycled
rats than in ad lib controls (149+/-5% vs. 117+/-7% of initial
baseline). Less weight was lost as a percent of starting body weight
during each successive VLCD, which could not be explained by aging.
At sacrifice, retroperitoneal fat pads were heavier in cycled SHROB
than in ad lib controls (62+/-3g vs. 44+/-4g). During the first 2d
after each VLCD, cycled rats overate significantly relative to ad lib
controls (88+/-2 vs. 78+/-3 kcal/d), but cumulative food intake
throughout the duration of the experiment did not differ (11.4+/-0.6
vs. 11.7+/-0.1 Mcal). Compared to ad lib fed rats, food efficiency (g
body weight gain/kcal) was increased during each refeeding period.
Weight cycling elevated blood pressure above the initial baseline
throughout refeeding. Refeeding hypertension was abolished by
ganglionic blockade with chlorisondamine. Thus, weight cycling in
SHROB exacerbates obesity, metabolic efficiency, abdominal fat
accumulation, sympathetic activity and hypertension.
Received 7 September 1994; accepted in final form 30 October
1995.
APS Manuscript Number R503-4.
Article publication pending Am. J. Physiol. (Regulatory Integrative
Comp. Physiology).
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on 30 November 95