Sex differences in proteins involved in CRFr internalization processes. (A) Blots represent the phosphothreonine band (red), CRFr band (green) and the merged image (yellow) indicating that both label the same protein (i.e., phosphorylated CRFr , MW=52 kDa). Protein for this blot was collected 24 h after stressor exposure. (B1-3) Bar graphs show the mean ratio of phosphothreonine:CRFr for each condition from tissue collected immediately [F(,)=0.39, p>0.05], 1 h [F(,)=0.58, p>0.05]or 24 h [F(,)=0.66, p>0.05] post-stress (n=4-6 determinations, pooled 3 rats per determination). (C) The Western blot shows the β-arrestin2 band (MW = 54 kDa) and the CRFr band 24 h after stressor exposure or handling. (D1-3) Graphs illustrate the ratio of β–arrestin2:CRFr for rats sacrificed immediately [F(,)=0.52, p>0.05], 1 h [F(,)=4.74, p<0.05] or 24 h post-stress [F(,)=5.77, p<0.05] (n=4-6 determinations, pooled 3 rats per determination). At both 1 and 24 h after stress, β–arrestin2 association with the CRFr was significantly increased in males (p<0.05) but not in females (p>0.05). Cycling females were included for an additional comparison at the 24 h timepoint, and there was no statistically significant difference in CRFr-β-arrestin2 association between ovariectomized and cycling females in either the unstressed or stressed condition (p>0.05). Data are represented as the mean (±SEM). Asterisks indicate a significant effect of stress compared to unstressed same sex control (p<0.05).