Lecture 18 - Histology Of The Adrenal Bland & Hormones Of The Adrenal Cortex

LECTURE 18: 10/29 Cortex Adrenal Gland B. Histology Cortex Zona glomerulosa outermost Cortex 2. Zona fasciculata middle Cortex 3. Zona reticularis innermost (cartes) Medulla inner most in totality Zona glomerulosa outermost region smallest pertion of cortex Secretes aldosterone MC sait balance not contrallied by ACTH Renin- Angiotensin System RAS zone does not secret. GGs. yomeruleus Zona fasciculata largest region middle layer secretes cortisol (F) and/or corticosterone (B)-GC controlled by ACTH (removal of pituitary) —> Atrophy of Z.F. ACTH —> hypertrophy of Z.F. (entage) Zona reticularis innermost region Sex honnones Secretes weak androgent DHEA DHEA AS controlled by ACTH, LH Secretion peaks at puberty Adrenarche pook Gaetrar & Hatt. 2001 Summary! only ZF. is part of the HPA axial Z.R. & G are not steroids GC (HPAT blagenic amines Fig 8-2 Other Zones. a. fetal zone The fetal zone * important for steroid (androgen) Synthesis during pregnancy largest zone at birth in human Shrinks rapidly after birth semen need Elevels to maintain placenta does not mate C. Hormones of the adrenal cortex P450 progesterone P950 Cortisol (GC) Corticosterone (oc) Aldosterone glucocorticoid secretion A. controlled by ACTH-zona fasiculata b. Circadian rhythms-24 hour my thims Human -ACTH peaks: 6-9 AM Cortisol peaks 7-9AM Rat -nocturnal ACTH peaks 6-9 PM Cortisol peaks: 7-9 PM inverse pattern 2. Androgen Secretion-Zona reticularis accelerates at puberty 15 yrs adrenarche remains high until middle age declines begin between 40-50 years Adrenopouse, etcuts siaund menopause difficult for mamen no daily pattern, lifetime pattern instead fetal sane pradicks andragens until lyr old Glucocorticoid Function a. Types of action metabolism (include permissive). immune reproduction development brain function permissive b. Receptor Types mineralcorticoid (MR) GR-1 glucocorticoid (GR) GR-2 C. effects on metabolism-ensures you have enough energy 1. inhibits glucose uptake by "peripheral" tissues everything except CNSbecause we want the givtose is be used BY the CNS to maintain vilal functiant especially inhibits muscle uplake glucose, steletal muscit may induce temporary hyperglycemia, lols will be in the blood (gleente) 2. Stimulate gluconeogenesis formation of glucose from amino acids ar fatty acids formation of gucose through non-carbohydrate sources a activales enzymes how it happenu PEPCK in liver-rate limiting trayme in gluconeogenesis liver kidneys only occurs here 3 Alters amino acid metabolism-only Ge can do this! Crowning pant causes protein catabolism in muacte (breakdown to A.A.) increase plasma amino acids levels. Stimulates amino acids uptaxe by liver 4 Enhances lipolysis coused by other hormones-permasive effect. GC do not directly cause lipetysis permits armers increases NEFA glycerel in plasma more gluconeogenic substrate glucose blood D. effects on immune system GC can supress inflammation-cortisone on bug bites-to supress immune response, used for no iransplant rejections (pharmaziagical) GCs can enhance t-lymphocytes E. influence on repraduction development fetal development pregnancy effect on laber (sheep) induce inbor effect on respiratory system stimulate cells to make surfactant inhibition of GTH secretion (genadetrapina) when stressed, reproduction is harder