Prenatal metabolic adversity reprograms insulin-responsive transcription in the developing nucleus accumbens.

Prenatal metabolic adversity, including fetal growth restriction (FR), programs long-term alterations in systemic and neural insulin sensitivity, yet its impact on insulin signaling within reward-circuit plasticity across development remains poorly understood. Using a rodent model of gestational FR, we examined how early metabolic stress alters insulin regulation of mesolimbic reward circuits using in vivo chronoamperometry to measure nucleus accumbens (NAc) dopamine (DA) release during palatable food exposure, with and without peripheral insulin. We assessed longitudinal consumption behavior and conducted transcriptomic profiling (RNA-Seq) at birth (P0), weaning (P21), and adulthood (P90) following saline or insulin administration. FR blunted immediate NAc DA release in response to palatable food, a deficit specifically reversed by peripheral insulin, indicating altered insulin sensitivity of mesolimbic reward circuits. FR animals also display accelerated initial palatable food consumption. Transcriptomic analysis revealed that FR reprograms the NAc's molecular response to insulin. Across development and sex, only 2-9% of insulin-responsive genes overlap between FR and controls. FR generated condition-specific and frequently inverted transcriptional signatures, affecting genes linked to synaptic plasticity (Cplx3, Rab3b) and neurodevelopment (Ccn3). These findings demonstrate that prenatal adversity reconfigures the NAc by altering its molecular and neurochemical responsiveness to insulin. This developmental reprogramming reveals how early metabolic stress reshapes insulin sensitivity within reward circuitry, a mechanism that may contribute to both metabolic and psychiatric disease vulnerability.