Overexpression of PRLR by Ad-PRLR improves insulin sensitivity under insulin-resistant conditions. A and B: HepG2 cells were exposed to Ad-PRLR (+ Ad-PRLR) or GFP (− Ad-PRLR) for 48 h prior to being incubated with (+ GlcN) or without
(− GlcN) 18 mmol/L glucosamine for 18 h in the presence of Ad, followed by stimulation with 100 nmol/L insulin for 20 min.
C: PRLR protein was analyzed by Western blot in the livers of wild-type (wt) and db/db (db) mice. D–F: Male C57BL/6J db/db mice were infected with Ad-PRLR (+ Ad-PRLR) or GFP (− Ad-PRLR) via tail-vein injection, followed by measurement of blood
glucose and serum insulin levels at days 11 and 7 in D and E, and performance of GTTs and ITTs at days 7 and 9 in F, respectively. The mean ± SEM values shown are representative of at least three independent in vitro experiments or at least
two independent in vivo experiments, with the number of mice included in each group in each experiment indicated (n = 5–7). Statistical significance was calculated using the two-tailed Student t test or one-way ANOVA followed by the SNK test for the effects of insulin-resistant vs. control group (*P < 0.05) in A--C, Ad-PRLR vs. the control group under insulin resistance (#P < 0.05) in B and D–F. A and B: PRLR, p-IR (tyr1150/1151), and p-Akt (ser473) protein (left, Western blot; right, quantitative measurements of PRLR, p-IR, and p-Akt protein relative to actin or their total protein). C: PRLR protein (top, Western blot; bottom, quantitative measurements of PRLR protein relative to actin). D: Blood glucose levels. E: Serum insulin levels. F: GTT and ITT. t, total.