Elevated neuropeptide Y (NPY) mRNA is not essential for obesity in brown Norway-Zucker (BNZ) fa/fa pups

B. L. Busch, P. R. Johnson, J. S. Stern, Barbara A Horwitz

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In adult obese (fa/fa) rats, hypothalamic NPY mRNA is higher than in lean rats, consistent with their hyperphagia and decreased sympathetic activity. We tested the hypothesis that elevated NPY mRNA contributed to the early development of obesity by assaying hypothalamic NPY mRNA levels in BNZ N2 pups. F1 female offspring from obese (fa/fa) male Zuckers and lean (+/+) female Brown Norway rats were back-crossed to their sires, resulting in 28 N2 litters, standardized to 7-10 pups/litter. Pups were decapitated at 2, 4, 7 & 12 days; spleen DNA was used to distinguish fa/fa from lean (+/fa) pups. Serum was assayed for glucose and insulin, hypothalami for NPY by RNAse protection assay, and eviscerated carcasses for body fat. Glucose, insulin, and % carcass fat were analyzed by 3-way ANOVAs followed, when the model was significant, by a 1-way ANOVA and 2-tailed post hoc test. NPY mRNA was analyzed by a 1-way ANOVA with a 1-tail posthoc test. There were no genotype differences in % fat except at day 12, when both % fat and insulin were significantly higher in fa/fa vs. +/fa pups. No genotype differences in glucose occurred at any of the tested ages. Nor were there significant genotype differences in hypothalamic NPY mRNA levels, although there was a trend toward higher levels in fa/fa male BNZs at day 12 (P=0.066). These data are consistent with the lack of hyperphagia in similarly aged Zucker fa/fa rats and show that elevated hypothalamic NPY mRNA is not necessary for enhanced adiposity in fa/fa pups.

Original languageEnglish (US)
JournalFASEB Journal
Issue number3
StatePublished - 1997

ASJC Scopus subject areas

  • Agricultural and Biological Sciences (miscellaneous)
  • Biochemistry, Genetics and Molecular Biology(all)
  • Biochemistry
  • Cell Biology


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