Gonadal steroid hormones and the hypothalamo-pituitary-adrenal axis.
The hypothalamo-pituitary-adrenal (HPA) axis represents a complex neuroendocrine feedback loop controlling the secretion of adrenal glucocorticoid hormones. Central to its function is the paraventricular nucleus of the hypothalamus (PVN) where neurons expressing corticotropin releasing factor reside. These HPA motor neurons are a primary site of integration leading to graded endocrine responses to physical and psychological stressors. An important regulatory factor that must be considered, prior to generating an appropriate response is the animal's reproductive status. Thus, PVN neurons express androgen and estrogen receptors and receive input from sites that also express these receptors. Consequently, changes in reproduction and gonadal steroid levels modulate the stress response and this underlies sex differences in HPA axis function. This review examines the make up of the HPA axis and hypothalamo-pituitary-gonadal (HPG) axis and the interactions between the two that should be considered when exploring normal and pathological responses to environmental stressors.
Department of Basic Medical Science, The University of Arizona College of Medicine, Phoenix, AZ 85004, United States. Electronic address: rhanda@arizona.edu.
Robert J
RJ
Handa
DSM Nutritional Products Ltd., R&D Human Nutrition and Health, Boulder, CO 80301, United States.
Michael J
MJ
Weiser
D000818:Animals; D003346:Corticotropin-Releasing Hormone / Q000502:physiology*; D012739:Gonadal Steroid Hormones / Q000502:physiology*; D006801:Humans; D007030:Hypothalamo-Hypophyseal System / Q000502:physiology*; D010913:Pituitary-Adrenal System / Q000502:physiology*; D011960:Receptors, Estrogen / Q000502:physiology; D013312:Stress, Physiological / Q000502:physiology*
D012739:Gonadal Steroid Hormones; D011960:Receptors, Estrogen; D003346:Corticotropin-Releasing Hormone
Androgen receptor; CRF; Dihydrotestosterone; Estradiol; Estrogen receptor; Glucocorticoid; HPA; HPG; Sex difference; Testosterone