1. MLAB 2401: Clinical Chemistry Keri Brophy-Martinez
Adrenal Gland: Overview

2. Introduction Adrenal Gland: An Overview
Produces steroid hormones & neuropeptides essential for life
Conditions affect blood pressure & electrolyte balance.
Hypofunction is treated with exogenous hormone replacement, hyperfunction with pharmacologic suppression or surgery.

3. Adrenals Composed of outer adrenal cortex & inner adrenal medulla
Pyramid-shaped, located just above & medial to kidneys
Glands are about the size of a grape
Arterial supply is symmetric; axons reach medulla through cortex.

4. Anatomy Zona Glomerulosa Zona Fasciculata Zona Reticularis
G-Zone Cells
outer 10%
Synthesize mineralocorticoids
Zona Fasciculata
F-Zone Cells
middle 75%
Synthesize glucocorticoids
Zona Reticularis
R-Zone Cells
inner 10%
Secrete sex steroids (androgens)

5. Classes of Adrenal Cortex hormones
Mineralocorticoids
Regulate electrolytes
Critical for sodium retention, potassium, & acid–base homeostasis
Aldosterone
Controlled by the renin-angiotension system
Promotes potassium secretion
Increases plasma sodium

6. Classes of Adrenal Cortex Hormones
Glucocorticoids
Involved with metabolism of protein, carbohydrate and mineral metabolism
Critical to blood glucose homeostasis & blood pressure
Plays a role in suppression of inflammatory and allergic reactions

7. Glucocorticoids Cortisol- principle member Functions
Acts be penetrating cell nucleus, binding DNA, and altering the transcription of RNA
Insulin antagonist
95% circulates bound to protein
Breaks down muscle proteins with enzymes
Mobilizes fat for energy purposes
Lessens immune response by inhibiting antibody formation

8. Cortisol Regulation
Hypothalamus secretes CRH (Corticotropin releasing hormone)
CRH activates adrenocorticotropic hormone (ACTH)in the anterior pituitary
ACTH controls cortisol production
Low levels of cortisol, promote ACTH release
Elevated levels of cortisol, inhibit ACTH release

9. Cortisol/Cortisone
Conjugated and excreted in the urine as 17- hydroxycorticosteroids (17-OHCS)

10. Classes of Adrenal Cortex Hormones
Sex steroids
Androgens
Testosterone is the principal androgen
Very little testosterone is secreted by the adrenal cortex

11. Adrenal Medulla Hormones
Characteristics
Produced in small amounts and extremely potent, rapidly inactivated
Amine-type of hormone
Produced from tyrosine, activate c-AMP
Mobilize energy stores and prepares body for muscular activity
Increased amounts secreted during stress

12. Catecholamine Members
Norepinephrine/ Noradrenaline
Epinephrine/Adrenaline
Increases blood glucose via breakdown of glycogen
Increases heart rate and blood pressure
Causes sweating and dilation of the eyes

13. Excretion of Catecholamines
Metabolism of catecholamines occurs by various pathways to form
Vanillylmandelic acid (VMA)
Metanephrine
Normetanephrine
Homovanillic acid