Endocrine intro Flashcards
Hormones are transported by
- blood in the circulatory system
- lymph fluids in the lymphatic circulation
- matrix of the interstitial spaces
- plasma within the cells
Hormones are chemical messengers that affect the function of:
Organs
Tissues
Cells
Intracellular organelles
other “players”
Endocrine system utilizes the nervous system, growth factors and cytokines in addition to hormones to coordinate functions of the body
What does the endocrine system do for me?
- Growth and Development
* Normal maturation - Homeostasis
* Thyroid = 25% of most basal metabolism
* Insulin/Glucagon and blood glucose regulation - Reproduction
* Fetal development through menopause
Five Major Classes of Hormones
- Amino acid derivative: dopamine, catecholamine, thyroid hormone
- Small neuropeptides: gonadotropin-releasing hormone (GnRH), thyrotropin-releasing hormone (TRH), somatostatin and vasopressin (ADH)
- Large proteins: insulin, leutinizing hormone (LH), PTH
- Steroid hormones: cortisol, estrogen – cholesterol based
- Vitamin derivatives: retinoids (Vit A), Vitamin D
Steroid hormones are produced in the?
Adrenal cortex, ovaries, testes and placenta
Cortisol and aldosterone
Estrogens (E1, E2, E3, …)
Androgens (DHEA, androstenedione, testosterone, DHT, …)
Progesterone
Pregnenolone
Vitamin D
Hormones activate targets via their receptors
Two Major Classes?
- Membrane:
Bind peptide hormones
Bind catecholamines (peptide hormones) - Nuclear
Bind steroids
Bind vitamins
Bind molecules that diffuse across membranes
Name 3 benefits of hormone binding:
Name 3 benefits of hormone binding
- The proteins may assist in the movement of substances by facilitated diffusion or active transport.
- Availability (Reservoir)
- Turn over (Prevents degradation) Ex. T4/T3 (Ex.-Binding protein-Sex horm. binding globulin)
Cases:
(Burn patient=Low albumin/Cancer=low Calcium bc more albumin)
Regulation of hormones is multimodal
Increased expression Utilization of precursors Release Available bound stores Degradation and metabolism
feedback and timing
- Feedback often is negative
* Occasionally positive – not well understood - Feedback to self, local area, distant sites (Ex.: thyroid)
- Timing or rhythm regulated by
* Environment
* Food
* Light/Dark cycles
* Menstrual (set)
Hormone classification of action site
1) Exocrine when they are secreted into the gastrointestinal tract
2) paracrine when they act on cells within the vicinity of the secreting cell
3) juxtacrine when they act on neighboring cells
4) autocrine when they act on the cell in which they are produced
Fastest half-life (Breakdown fastest) Hormone?
Neurotransmitters (test metabolites)
The biochemical longevity (T1/2) of hormones (half life)
increased by binding to carrier proteins
increased by stable reservoirs of precursor substances
increased by glycosylation (His Ex: Diabetes-Other hormones sugary (RBC-Frosted donuts=>Hemoglobin A1C
Causes of endocrine disease
Nutritional deficiencies Environmental challenges Nonspecific “stress” Autoimmune processes (Especially-> Hypo-function) Genetic factors Neoplastic disease Multifactorial causes
3 themes describe endocrinology:
Hyper secretion, hypo secretion, no response
When does the endocrine system become pathologic
- Excessive hormone production
Neoplasms
Autoimmune disease
Iatrogenic - Deficiency in hormones
* Autoimmune disease
* Infectious
* Inflammatory
* Infarction
* Neoplasms (Pituitary-Hyperfunction/cells around it hypo function)
* Iatrogenic - Resistance to hormones
Functional down-regulation
Functional desensitization
Genetic defects
Endocrine Laboratory Tests
- End organ hormone tests (e.g. T4, T3, cortisol, estrogens, progesterone, DHEA, DHEA-S, and testosterone.
- Anterior pituitary hormone tests (e.g. TSH, ACTH, FSH, and LH) test HPT-axis, HPA-axis, and HPG-axis.
- Suppression tests (e.g. dexamethasone suppression testing)
- Provocative tests (e.g. arginine administered for GH provocation testing)
- Functional tests (e.g. deep tendon reflex evaluation in suspected hypothyroidism)
EX.-Hyper=Cushings-high cortisol (Morning)=Try to suppress, goes down ( dethomethesone) gland is too much. or gland not responding.
EX.-Hypo-Stem. hormone-nothing happens- organ damage can’t make or no one is listening (diabetes?? which one?) receptor issue..
Intervention - life-style modification to treat underlying causes
Diet, adequate nutrition Physical activity Adequate exposure to light, pure air Adequate sleep, rest, recreation Meaningful activities Avoidance of exposure to detrimental environmental influences
Intervention –Pharmacologic and Non-Pharmacologic Approaches (True gland destruction-stuck w/hormone replacement)
Ex-Type 1 diabetic-Needs insulin
- Hormone replacement
- Pharmaceutical and herbal stimulant or suppressive substances
- Surgical (in malignancy)
- Supportive therapies
Herbal therapies
Specific dietary choices
Supplemental co-factors
Energetic Medicine
How many classes of hormones are described?
5
Name 5 hormones types
Amino acid derivative: dopamine, catecholamine, thyroid hormone
Small neuropeptides: gonadotropin-releasing hormone (GnRH), thyrotropin-releasing hormone (TRH), somatostatin and vasopressin (ADH)
Large proteins: insulin, leutinizing hormone (LH), PTH
Steroid hormones: cortisol, estrogen – cholesterol based
Vitamin derivatives: retinoids (Vit A), Vitamin D
Which class of hormones have the longest half life? The shortest?
Steroids & Neural
Steroid hormones usually bind which type of receptor?
Nuclear
What is the most prevalent endocrine disorder?
false (no-obesity is now)
