AJP - Regulatory, Integrative and Comparative Physiology, Vol 270, Issue 6 1208-R1214, Copyright © 1996 by American Physiological Society
Effects of gold thioglucose on neuropeptide Y messenger RNA levels in the mouse hypothalamus
J. L. Marks, K. Waite, D. Cameron-Smith, S. C. Blair and G. J. Cooney
Department of Clinical Endocrinology, Westmead Hospital, New South Wales, Australia.
Elevated hypothalamic neuropeptide Y (NPY) expression is found in several
rodent genetic models of obesity, but any association in nongenetic models
of obesity is unclear. Consequently, we have measured NPY mRNA levels in
the ventromedial hypothalamus of a well-characterized model of obesity, the
gold thioglucose (GTG)-injected mouse. Fourteen days after injection (early
stage), animals were hyperphagic but not obese, hyperglycemic, or overtly
hyperinsulinemic. Ten weeks after treatment (late stage), animals were
obese, markedly hyperinsulinemic, and hyperglycemic. In both the early and
late stages, NPY mRNA levels were reduced in the arcuate nucleus of
GTG-injected animals. Although overnight fasting doubled NPY mRNA levels in
control animals, there was no change at either stage in GTG-injected
animals. NPY mRNA levels in the deep layers of the cerebral cortex and in
the dentate gyrus were not affected by GTG treatment or overnight fasting.
We conclude that GTG treatment reduces the expression of NPY mRNA in the
arcuate nucleus and that, therefore, increased hypothalamic NPY expression
is unlikely to be an important factor causing the obesity and other
metabolic changes found in this model.
