Decreased fertility and birth rates are afflictions arising from metabolic disorders. This study assesses cholesterol metabolism and Cx46, Cx50, Cx43 expression in interstitium- and seminiferous tubule-enriched fractions of leptin-deficient (ob/ob) and leptin receptor-deficient (db/db) mice, two type 2 diabetes and obesity models associated with infertility. Testosterone decreased, glucose, free and esterified cholesterol increased in serum whereas in interstitium, free and esterified cholesterol decreased in ob/ob and db/db. In tubules, a drop in esterified cholesterol caused free-to-esterified cholesterol ratios to augment in db/db. In tubules, only ACAT-1 and ACAT-2 protein levels significantly decreased in ob/ob not in db/db compared to WT and cholesterol transporters NPC1, ABCA1, SRBI and CD36 were imbalanced in both ob/ob and db/db. In tubules, 14kDaCx46 prevailed during development, 48-49 and 68-71kDaCx46 during adulthood; total Cx46 changed little. Compared to WT, 14kDaCx46 augmented whereas 48-49 and 68-71kDaCx46 diminished in tubules whereas the opposite occurred in interstitium in db/db and ob/ob. Total Cx50 and 51kDaCx50 increased in db/db and ob/ob interstitium and tubules. Cx43 levels decreased in ob/ob interstitium and tubules whereas in db/db, Cx43 decreased in interstitium but increased in tubules. Apoptosis levels measured by ELISA and apoptotic cell numbers labelled with Apostain significantly augmented in db/db not in ob/ob tubules. Testicular db/db capillaries were Cx50-positive but weakly Cx43-positive with a thickened lamina suggesting altered permeability. Our findings indicate that the db mutation-induced impairment of meiosis may arise from imbalances in cholesterol metabolism and upregulated Cx43 expression and phosphorylation in tubules.