Fig. 4

a Insulin receptor β-subunit levels in anterior pituitaries of leptin receptor-deficient (db/db) and leptin-deficient (ob/ob) and wt male mice. Thirty microgram of total protein samples were loaded per well. After electrophoretic migration, proteins were electrotransferred onto nitrocellulose membranes and probed with anti-IR-β subunit. Bands were scanned and their intensity quantified. The figure shows a representative western blot. The values are the mean ± SEM of 3 different animals in each experimental group. Total IR-β subunit levels were significantly lowered in (###P < 0.0002) db/db and (bP < 0.00005) ob/ob compared to wt counterparts. The full-length IR-β subunit levels decreased in (**P < 0.005) db/db and (* < P0.05) ob/ob mice compared to wt. The fragmentation increased in db/db and ob/ob mice by comparison to the wt: 50 kDa levels: (***P < 0.0005) db/db (###P < 0.0002) ob/ob; 66 kDa levels: (iP < 0.00003) db/db (†††P < 0.0001) ob/ob; 75 kDa levels: (* < P0.05) db/db. b Insulin receptor α-subunit expression in the leptin receptor-deficient (db/db) and leptin-deficient (ob/ob) and wt mice. Thirty μg of total protein samples were loaded per well. After electrophoretic migration, proteins were electrotransferred onto nitrocellulose membranes and probed with anti-IR-α subunit. Bands were scanned and their intensity quantified. The figure shows a representative western blot. The values are the mean ± SEM of 3 different animals in each experimental group. Total IR-α subunit levels were significantly higher in (* P > 0.05) db/db mice compared to the wt. The values did not significantly differ in ob/ob mice from the wt counterparts. The full-length IR-α subunit (135 kDa) levels were not significantly different in the three experimental groups. Only the (#P > 0.02) 36 kDa and (##P < 0.002) 50 kDa IR-α subunit fragments levels significantly increased in db/db mice compared to wt. c and d Soluble (s)IR-α levels in the serum in db/db, ob/ob and wt mice. Results obtained in c using an anti-IR-α polyclonal antibody for both, immunoprecipitation and western blotting and in d using anti-IR-α polyclonal antibody for immunoprecipitation then, using an anti-IR-α monoclonal antibody for western blotting. c In the serum of db/db mice, the rise in (##P < 0.002) 110-, (@P < 0.000001) 90-, (*P < 0.05) 75-, (***P < 0.0005) 50- and (**P < 0.005) Total sIR-α levels is significant compared to the wt counterparts. As well, the upsurge in 110- (aP < 0.00001) 110-, (eP < 0.000005) 90-, (†††P < 0.0001) 75-, (††P < 0.001) 50- and (cP < 0.000002) Total sIR-α in the ob/ob mice is significant compared to the wt counterparts. The control done on PBS shows an intense band around 50 kDa and a faint one around 21 kDa. d The (cP < 0.000002) 110-, (@P < 0.000001) 90-, (bP < 0.00005) 75-, (‡P < 0.03) 50- and (bP < 0.00005) Total sIR-α increase in the db/db mice compared to the wt counterparts. The (†††P < 0.0001) 110-, (aP < 0.00001) 90-, (†††P < 0.0001) 75-, (‡‡‡P < 0.003) 50- and (†††P < 0.0001) Total sIR-α levels increase in the ob/ob mice compared to the wt counterparts