Fig. 4: Loss of OMP expression increases basal PRL levels and leads to TRH desensitization in vivo.

a Basal circulating PRL levels in OMP-WT (+/+), OMP-heterozygote (+/−), and OMP-KO (−/−) mice, as determined by ELISA. Values represent the mean ± SE (OMP+/+, n = 6; OMP+/−, n = 6; OMP−/− n = 6). *P < 0.05 vs. +/+ group. b ERK1/2 phosphorylation in OMP+/+ or OMP−/− anterior pituitary tissue treated with saline or TRH (1 μM), as determined by western blotting. β-Actin served as a loading control. c PRL levels in the culture supernatant of OMP+/+ and OMP−/− anterior pituitary tissue treated with saline or TRH (1 μM), as determined by ELISA. Results represent the mean of at least three independent experiments. ns, not significant; *P < 0.05 vs. (−) control