We induced high fat diet (HFD) obesity in low-density lipoprotein receptor knock-out Leiden (Ldlr−/−.Leiden) mice, and studied the morphological structure of the testes and histologically examined the proportion of Sertoli cells, spermatocytes and spermatids in the seminiferous tubules. Here, LDLR is linked to obesity due to melanocortin 4 receptor deficiency.