2.3. Corticosterone radioimmunoassay (RIA)

Plasma samples were diluted 1 in 50 with citrate buffer (pH 3.0). Total plasma corticosterone levels were measured from blood samples with an in-house RIA as previously described (Atkinson et al., 2006, Spiga et al., 2007, Waite et al., 2012) using a specific rabbit anti-rat corticosterone primary antibody (kindly supplied by G. Makara, Institute of Experimental Medicine, Budapest, Hungary). The intra- and inter-assay coefficients of variation of the corticosterone assay have previously been established as 16.7% and 13.3%, respectively (Spiga et al., 2011).