Salivary diurnal glucocorticoid profiles in monozygotic twins with intra-twin birthweight-differences.

In monozygotic twins with intra-twin bw-differences, intra-twin catch-up growth showed a moderate influence on intra-twin differences in morning cortisol concentrations. We observed no differences regarding diurnal patterns. In contrast, in all groups, we found significant intra-twin correlations for cortisol and cortisone over the day and a pronounced graphic alignment of cortisol diurnal patterns. We therefore suggest a predominant significance of the genetic background compared with bw-differences on cortisol metabolism.