Associations between early life stress and anterior pituitary gland volume development - A novel index of long-term hypothalamic-pituitary-adrenal axis functioning.

Previous research has established associations between early life stress (ELS) and altered pituitary gland volume (PGV) growth during adolescence. The pituitary gland, however, is composed of an anterior and a posterior lobe with distinct histological and neuroendocrinological properties. While the anterior (but not posterior) pituitary gland is directly involved in the hypothalamic-pituitary-adrenal axis (HPAA) stress response, no studies have examined the effects of ELS on anterior PGV (aPGV). The present study investigated whether previously reported associations between ELS and PGV development during adolescence were driven by aPGV versus posterior PGV (pPGV). Ninety-one adolescents (49 males) were included from a longitudinal, community-based adolescent development study investigating risk for psychopathology. ELS (maternal affective behavior, childhood maltreatment, stressful life events) was assessed during early adolescence. Participants underwent two waves of structural magnetic resonance imaging during mid- and late-adolescence, and aPGV and pPGV were manually traced. Regression analyses showed that childhood maltreatment predicted greater aPGV growth in females. This finding was stronger than that previously reported for PGV. No associations were found between ELS and pPGV development. Neither aPGV nor pPGV changes mediated associations between ELS and psychopathology. Results suggest that ELS may accelerate aPGV (but not pPGV) growth throughout adolescence. Investigating the development of aPGV, rather than PGV, represents a novel approach to studying the effects of stress on HPAA functioning.

Associations between early life stress and anterior pituitary gland volume development during late childhood.

Early Life Stress (ELS) is thought to influence Hypothalamic-Pituitary-Adrenal-Axis (HPAA) functioning, contributing to an increased risk for psychopathology through dysregulation of biological stress responses. Research exploring relationships between ELS and HPAA functioning has largely focused on its key hormonal output, cortisol. However, findings have been inconsistent, potentially due to cortisol's distinctive diurnal patterns and dynamic nature complicating its accurate measurement. Thus, this study explored the link between ELS and a more stable, structural component of the HPAA, specifically, anterior pituitary gland volume (PGV) in a community sample of children (N = 129, 68 female). PGV was traced from Magnetic Resonance Imaging brain scans across two time-points at ages 8 (baseline) and 10 years (follow-up). ELS exposure was assessed at baseline through parent-report questionnaires and maternal affective behavior observed in mother-child interaction tasks. ELS variables were reduced to a 5-factor structure using exploratory factor analysis - Uninvolved Parenting, Negative Affective Parenting, Neglect, Trauma, and Dysfunctional Discipline. Direct and sex-moderated associations between ELS and PGV were explored using regression and linear mixed models analyses. PGV-mediated associations between ELS and internalizing symptoms were also investigated. Childhood Neglect was significantly associated with greater baseline anterior PGV, that was stable over the follow-up period. This effect was found in the whole sample, and in males, specifically. No mediation effects were found. Results suggest that neglect may play a unique role in HPAA neurodevelopment; however, it is important that future research extends into adolescence to more clearly characterize these neurodevelopmental associations and any subsequent psychopathological outcomes.