CASP1 and obesity due to melanocortin 4 receptor deficiency: Here we find that high fat diet-induced increases in expression of monocyte/macrophage marker F4/80 was not affected by genotype, suggesting that caspase-1 is important for regulating the sensitivity of Kupffer cells to activation during high fat diet-induced obesity, rather than recruitment and/or proliferation of Kupffer cells in the liver.