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- ACTH Adrenocorticotropic hormone
- ADH Antidiuretic hormone (vasopressin)
- APS Autoimmune polyglandular syndrome
- AVP Arginine vasopressin
- CBG Corticosteroid-binding globulin
- CRH Corticotropin-releasing hormone
- DAX1 Dosage-sensitive sex reversal-adrenal hypoplasia gene product
- DHEA Dehydroepiandrosterone
- DOC Deoxycorticosterone
- GH Growth hormone
- GIP Glucose-dependent insulinotropic peptide/Gastrointestinal inhibitory polypeptide
- GnRH Gonadotropin-releasing hormone
- HLA Human leukocyte antigen
- HPA Hypothalamic-pituitary-adrenal
- HPLC High-performance liquid chromatography
- IL Interleukin
- IPSS Inferior petrosal sinus sampling
- IRMA Immunoradiometric assay
- LH Luteinizing hormone
- LPH Lipotropin
- PMN Polymorphonuclear neutrophi
- PRA Plasma renin activity
- PRL Prolactin
- PTH Parathyroid hormone
- SF-1 Steroidogenic factor-1a
- SHBG Sex hormone–binding globulin
- StAR Steroidogenic acute regulatory protein
- TRH Thyrotropin-releasing hormone
- TSH Thyroid-stimulating hormone (thyrotropin)
- VLCFA Very long chain fatty acid
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The adrenal cortex produces many steroid hormones of which the most important are cortisol, aldosterone, and the adrenal androgens. Disorders of the adrenal glands lead to classic endocrinopathies such as Cushing syndrome, Addison disease, hyperaldosteronism, and the syndromes of congenital adrenal hyperplasia. This chapter describes the physiology and disorders of the glucocorticoids and the adrenal androgens. Disorders of aldosterone secretion are discussed in Chapter 10 and congenital defects in adrenal hormone biosynthesis in Chapters 10 and 14. Hirsutism and virilization (which reflect excess androgen action) are discussed in Chapter 13.
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Advances in diagnostic procedures have simplified the evaluation of adrenocortical disorders; in particular, the assay of plasma glucocorticoids, androgens, and adrenocorticotropin (ACTH) has allowed more rapid and precise diagnosis. In addition, advances in surgical and medical treatment have improved the outlook for patients with these disorders.
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The adrenal cortex is of mesodermal origin and derives from a single cell lineage characterized by expression of certain transcription factors such as steroidogenic factor-1 (SF-1). At 2 months' gestation, the cortex, already identifiable as a separate organ, is composed of a fetal zone and a definitive zone similar to the adult adrenal cortex. The adrenal cortex then increases rapidly in size; at mid gestation, it is considerably larger than the kidney and much larger than the adult gland in relation to total body mass. The fetal zone makes up the bulk of the weight of the adrenal cortex at this time. Several genes encoding transcription factors are important in adrenal development and differentiation. These include SF-1 and the product of the dosage-sensitive sex reversal–adrenal hypoplasia gene (DAX1), among others; mutations of the DAX1 gene are associated with congenital adrenal hypoplasia.
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The fetal adrenal is under the control of ACTH by mid pregnancy, but the fetal zone is deficient in the activity of 3β-hydroxysteroid dehydrogenase (see section on biosynthesis of cortisol and adrenal androgens, later) and thus produces mainly dehydroepiandrosterone (DHEA) and DHEA sulfate, which serve as precursors of maternal-placental estrogen production after conversion in the liver to 16α-hydroxylated derivatives. The definitive zone synthesizes a number of steroids and is the major site of fetal cortisol synthesis. Mutations of the ACTH- or melanocortin-2 receptor gene are associated with familial glucocorticoid deficiency.