Exam 2: Lecture X, Endocrine System Flashcards
Endocrine System Regulates
Homeostasis Long-term Metabolic Processes RBC production Growth and Development Reproduction and differentiation
“Hormone” info
secreted directly into blood stream
Act at long range, and slowly on distant organs and tissues
Anterior Pituitary Gland
- Hypothalamus secretes 7 hypothalamic hormones into portal system (H1)
- APG secretes 7 pituitary hormones (H2)
- Glands of internal secretion release hormones in blood (H3)
Posterior Pituitary Gland
- Hypothalamus secretes 2 hormones through PPG
2. ADH + Oxytocin
Complexity of Endocrine System
- single gland can produce multiple hormones
- single hormone maybe secreted different glands
- single hormone may induce more than 1 type of effect
- rate of hormone may vary considerable
- single target can be effected by more than 1 hormone\
- same messenger maybe hormone or NT
Hormone Secretion can occur in…
Pulses (ie every 15 min)
Constant (steroid secretion)
Rhythms
Hormone Half-life
Seconds, Minutes, Days
Within CNS
Hypothalamus (command center)
Pituitary (Master gland)
Pineal
Endocrine activity regulated by….
Neg/Pos Feedback
Neuroendocrine reflexes
Circadian Rhythms
Endocrine disorders….
Hormone Hypo-/Hyper-secretion
Abnormal Target
Hormone Classes
Peptides
Steroids
Amines (Catecholamines/ Thyroid Hormone)
Peptide Info
Structure: chain of specific amino acids
Solubility: Hydrophilic - water soluble
Transport: Free Hormone
Receptor Site: Surface of target cells
Steroid Info
Structure: Cholesterol Derivative
Solubility: Lipophilic - Lipid soluble
Transport: Mostly bound to plasma protein
Receptor Site: Inside of target cells
From Adrenal Cortex, Gonads, Placenta
Amines (Catecholamines) info
Structure: Tyrosine Derivative
Solubility: Hydrophilic - water soluble
Transport: 50% bound to plasma protein
Receptor Site: surface of target cells
From Adrenal Medulla
Amines (Thyroid Hormone) info
Structure: Iodinated Tyrosine Derivative
Solubility: Lipophilic - Lipid soluble
Transport: Bound to plasma protein
Receptor Site: Inside of target cells
From Thyroid follicular cells
Water Soluble (Peptides/Catecholamines)
dissolved in plasma
cannot pass through lipid membrane
Bind with surface membrane receptors
Lipid Soluble (Steroids/Thyroid hormone)
bound in plasma with plasma proteins
enter cell across the membrane
bind with nuclear receptors -HRE
Growth Hormone (GH, Somatotropin)
stimulates cell growth, body growth
triggers release of somatomedins from liver cells
Thyroid Stimulating Hormone (TSH, thyrotropin)
stimulates growth of thyroid gland
triggers release of thyroid hormone
Adrenocorticotropic Hormone (ADCTH, corticotropin)
stimulates adrenal gland
stimulates glucocorticoids release
Melanocyte-Stimulating Hormone (MSH)
stimulates melanin production
Follicle Stimulating Hormone (FSH, folliculotropin)
stimulates estrogen secretion
stimulates egg development in women
stimulates sperm production in men
Luteinizing Hormone (L.H, Luteotropin)
causes ovulation and progestin production in women
causes testes to secrete test production in men
Prolactin (PRL)
stimulates development mammary glands and milk production
may enhance immune system
Posterior Pituitary Gland
extension of hypothalamus
hormones synthesized in neurons in hypothalamus
Hypothalamus and PPG act as unit
PPG secretes ADH/Vasopressin and Oxytocin
Vasopressin (ADH)(Vasostrict,Pitressin)
synthesized 9 AA peptide
Replaced hormone extracted from animal posterior pituitary
Half life = 15 min
Activates V1/V2 coupled receptors G-protein
Treatment - Diabetes insipidous/esophageal varices bleeding
V1 receptors found….
on vascular smooth muscles (Vasoconstriction)
V2 receptors found….
on renal tubule (antidiuretic effect)
Desmopressin (DDAVP)
LA synthetic analogue of Vasopressin
Minimal pressor, strong Antidiuretic activity
Half life = 1.5-2.5 hrs
Relatively selectively activates V2 coupled receptors of G-protein
V2 coupled receptors increase H20 reabsorption in collecting tubules (Antidiuretic effect)
Extrarenal V2 receptors regulate factor VIII and von Willebrand disease
Desmopressin Treatments
diabetes insipidous pediatric enuresis (bed wetting) Hemophilia A and von Willebrand disease
Oxytocin (Pitocin)
9 AA peptide hormone
circulates in blood in free form
half life = 5min
operates through G-protein coupled
Stimulates release of prostaglandins/leukotrienes
participates in labor/delivery
elicits milk ejection in lactating women
Oxytocin treatments
induction and augmentation of labor
control of uterine hemorrhage after delivery
Oxytocin Clinical Pharmacology
used to induce early vaginal delivery
used in maternal diabetes, preeclampsia, or ruptured membranes
used to augment protracted labor
used to control uterine bleeding in immediate postpartum period
Oxytocin Toxicity
When used judiciously, severe toxicity rare
induced uterine contractions may reduce blood flow to fetus
High conc + vasopressin receptor activation may cause water intoxication
Bolus inj can cause hypotension
Water intoxication
hyponatremia, heart failure, seizures, death
Atociban (Tociban)
Oxytocin Antagonist
Admin IV, blocks Oxytocin receptors, decrease uterine contractions
