2.3. Statistical Analysis

We conducted a quadratic analysis of life course changes in all endocrine variables. PND 21 values were excluded from analysis in all data sets due to proximity to weaning with its attendant marked influence on the offspring of lactation and approach of puberty, which is accompanied by many rapid changes occurring over just a few days. Corticosterone values at PND 110 and 220 were similar and also similar at PND 650 and 850. With this in mind, we simplified the construction of the life course corticosterone trajectory by restricting the corticosterone data analysis to PND 220, 450, and 650. From these trajectories, we calculated the timing of the peak corticosterone concentration and its value. PND 21 DHEA was excluded for similar reasons to corticosterone values. PND 850 DHEA values were included in the quadratic analysis since there was a continued DHEA fall in RR in both sexes and RC in males.

We analyzed the two sexes separately. CC female corticosterone was higher than male at PND 220 and 450 (p < 0.01 by non-paired t-test), CC female DHEA was higher than male at all ages except PND 220 (p < 0.05), and DHEA: CORT ratio lower at PND 220 and 450 (p < 0.01). Therefore, the sexes were analyzed separately throughout.