Lack of microglial InsR function leads to impaired microglial morphology and phagocytic capacity in the arcuate nucleus of female mice. (A) Iba1-ir microglia in the arcuate nucleus, Iba1-ir (B) soma number, and (C) primary projections (n = 6–8). There was a borderline significant decrease in microglial soma number in InsR-KO females, compared to InsR-Ctrl mice, when fed an obesogenic diet. InsR-KO mice had lower primary projections compared to InsR-Ctrl mice, irrespective of diet. (D,E) CD68-ir co-localization with Iba1-ir microglia in the ARC (n = 4–5). InsR-KO female mice had higher CD68-ir, compared to InsR-Ctrl mice under physiological conditions. Data presented for female InsR-Ctrl and InsR-KO mice fed a Chow diet (black) or HFD (green) following 12 weeks of diet exposure. Data are presented as mean ± SEM. * p < 0.05. III—3rd ventricle. Scale bar: 100 µm in (A); 10 µm in (D).