Diet-induced obesity and prenatal undernutrition lead to differential neuroendocrine gene expression in the hypothalamic arcuate nuclei.

Previously we reported that prenatal undernutrition (UN) leads to a dysregulation of appetite suppression through alterations in hypothalamic neuropeptide gene expression. In the current study, we expand our observations and investigate neuroendocrine transcriptional responses and central leptin sensitivity within the arcuate nucleus of rats exposed to prenatal UN or a postnatal high-fat diet (HF). Pregnant Wistar rats were fed a standard chow diet either ad libitum (AD) or at 30 % of AD intake throughout gestation (UN) resulting in either control or intrauterine growth-restricted female offspring. At weaning, AD offspring were fed either a chow (C) or a HF (30 % fat wt/wt) diet ad libitum for the remainder of the study, whereas UN offspring were fed a chow diet only. At ~142 days, AD and UN offspring received either recombinant rat leptin (L) or saline (S) subcutaneously for 14 days. Prenatal UN had a significant effect on hypothalamic NPY (P < 0.0001), AgRP (P < 0.01) and ObRb (P < 0.02) mRNA expression compared to AD chow-fed offspring. A postnatal HF diet had a significant effect on AgRP mRNA expression (P < 0.001), compared to AD chow-fed offspring, but no effect on NPY and ObRb expression. Leptin treatment, in both UN and HF offspring, was ineffective in reducing NPY and AgRP mRNA expression, and had no effect on ObRb expression. These findings suggest that prenatal UN and a postnatal HF diet lead to differential neuroendocrine gene expression in the hypothalamic arcuate nuclei and reduced sensitivity to leptin's anorexigenic effects.