Akademik Veri Yönetim Sistemi
Theriogenology, cilt.259, 2026 (SCI-Expanded, Scopus)
The dog ovary undergoes dynamic and metabolic remodeling during prepubertal development and throughout the estrous cycle. Peroxisome proliferator-activated receptors (PPARs) are ligand-activated nuclear transcription factors that regulate lipid metabolism and cellular differentiation; however, their stage-specific spatial regulation in the dog ovary remains poorly defined. This study characterized the compartment-specific localization and semi-quantitative abundance patterns of PPARα, PPARδ, and PPARγ in prepubertal and cyclic sexually mature dogs. Ovarian tissues were obtained from 10 prepubertal bitches and 40 adult bitches representing proestrus, estrus, diestrus, and anestrus. Immunofluorescence staining was performed, and expression in granulosa and luteal cells was evaluated using a semi-quantitative scoring approach. All three PPARs were present based on cell-type and stage-dependent nuclear immunoreactivity within granulosa and luteal tissues. Granulosa PPARγ exhibited greater abundance in estrus (p ≤ 0.05) and diestrus (p ≤ 0.001) than in anestrus, and luteal PPARγ nuclear immunoreactivity was increased in diestrus (p ≤ 0.01). Granulosa PPARα levels were lower in prepubertal ovaries than in estrus and diestrus (p ≤ 0.05), whereas luteal PPARα levels were higher during diestrus compared with anestrus (p ≤ 0.001). Granulosa cell PPARδ reached its highest levels during estrus relative to prepubertal and anestrus stages (p ≤ 0.05–0.01), and remained elevated during diestrus compared with anestrus (p ≤ 0.05). Collectively, these findings demonstrate PPAR-specific, stage-dependent, and tissue-specific regulation of PPARs in the canine ovary. The pronounced diestrus-associated nuclear enrichment of PPARγ, the metabolically coherent modulation of PPARα, and the sustained distribution of PPARδ suggest coordinated metabolic adaptation during ovarian follicular maturation and prolonged luteal function in the dog, while the detection of all PPARs in prepubertal ovaries indicates that PPAR-mediated regulatory networks are established prior to endocrine cyclicity during the dog reproductive cycle.