AJP - Regulatory, Integrative and Comparative Physiology, Vol 247, Issue 2 308-R317, Copyright © 1984 by American Physiological Society
Regeneration may mediate the sparing of VMH obesity observed with prior vagotomy
E. A. Fox and T. L. Powley
The extent to which the vagus nerve is involved in mediating the
development of obesity in animals with lesions of the ventromedial
hypothalamus (VMH) was determined. Female rats were given either VMH
lesions or sham lesions 100 days after they had received vagotomy with
pyloroplasty, sham vagotomy with pyloroplasty, or sham vagotomy with sham
pyloroplasty. For the first 7 postlesion wk, the animals were fed a wet
mash diet, then they were maintained on a high-fat diet for 10 wk, and
finally they were fed a highly palatable supermarket diet for 4 wk.
VMH-lesioned animals with prior vagotomy and pyloroplasty displayed 65% of
the obesity observed in lesioned animals with prior sham vagotomy. This
expression was increased to 72% of the full VMH obesity during the
supermarket diet phase. Assessment of vagotomy suggested that vagal
regeneration and, in some cases, recovery of vagally stimulated insulin
secretion had occurred. This reorganization may have contributed to the
residual obesity expressed in VMH-lesioned animals with prior vagotomy.
