Abstract
<title>Abstract</title> <p>Maternal exposure to benzophenone-3 (BP3; oxybenzone) during successive pregnancies produces litter-dependent alterations in ovarian function. We previously found that adult female offspring from the second pregnancy exhibited impaired ovulatory responsiveness to gonadotropin stimulation, whereas first-litter offspring retained a normal response. Whether intrinsic differences in the ovarian molecular landscape are already established before gonadotropin stimulation and contribute to this divergent phenotype remains unknown. We therefore investigated the basal ovarian proteome of prepubertal female offspring born from the first and second pregnancies of dams topically exposed to BP3 (50 mg/kg/day) or vehicle during gestational days 0–9. Ovaries were collected on postnatal day 21 and analyzed by label-free liquid chromatography–tandem mass spectrometry, followed by functional enrichment and pathway mapping. BP3 exposure produced distinct, litter-dependent proteomic responses. First-litter offspring showed 25 differentially abundant proteins, mainly involving cytoskeletal organization, desmosomal components, and signaling pathways potentially related to tissue remodeling and functional compensation. In contrast, second-litter offspring displayed 48 differentially abundant proteins, with a predominance of decreased abundance. These changes were enriched in fatty acid β-oxidation, oxidative phosphorylation, mitochondrial function, proteasome regulation, and chromatin remodeling. Key reductions included proteins involved in mitochondrial energy production and lipid catabolism. These findings indicate that ovarian molecular differences are already present before gonadotropin stimulation. The second-litter ovary exhibited a metabolically vulnerable proteomic profile that may contribute to the impaired gonadotropin responsiveness previously observed in adulthood.</p>