Test 1 Flashcards
_______hormones are examples of_________ derivatives that are chemically similar to steroid hormones
Thyroid
tyrosine
__________________ are examples of____________ derivatives that are chemically similar to protein hormones
Epinenephrine & norepinephrine (catecholamines)
tyrosine
Episodic release of hormone of about an hour.
Circhoral
Episodic release of hormones longer than an hour but less than 24 hrs.
Ultradian
Episodic release approximately every 24 hrs
Circadian
Episodic activity that is expressed at defined periods of the day
Diurnal (D for defined)
Episodic release of hormones approximately every month (30 days)
Circatrigintan
This disorder is a form of postpartum pituitary necrosis or infarction.
Sheehan’s syndrome
Hypopituitarism, particularly a form resulting in hypogonadotropic hypogonadism.
Hemochromotosis
The paraventricular nucleus produces…
OXYTOCIN
The supraoptic nucleus produces…
ADH
the most important physiologic stimulus for increasing ADH secretion
increase in osmolarity
The second most potent stimulus for ADH secretion
Hypovolemia, or volume contraction (e.g., due to hemorrhage)
Other Factors inhibiting ADH secretion
Ethanol
a-Adrenergic agonists
Atrial natriuretic peptide
The target tissue of ADH and its effect
Effect: Water resorption of by the kidneys
Targets: Principal cells of the distal convoluted tubule and collecting duct.
Which receptors does ADH bind to?
V2 receptors in the kidneys
V1 Receptors in smooth muscle
What is the secondary action of ADH?
Constriction of arteriolar vascular smooth muscle causing vasoconstriction.
Decreased ADH secretion results in which disease?
Neurogenic (Central) Diabetes Insipidus
ADH is released from
The posterior pituitary
In adults, the major clinical manifestations of diabetes insipidus include abnormal specific gravity of urine. What is normal and what is not?
The urine is dilute with specific gravity below 1.005, and an osmolality less than 200mmol/kg/24hr
A disorder that results compulsive water drinking, not associated with excess ADH secretion.
Primary Polydipsia
Medication taken for ONLY for neurogenic (central) diabetes insipidus
Desmopressin (DDAVP)
Disease suspected in any patient with hyponatremia, plasma hyposmolality, and elevated urinary sodium excretion
Syndrome of Inappropriate ADH (SIADH)
Most common etiology is ectopic production of ADH by small cell (oat cell) carcinoma of the lung
Syndrome of Inappropriate ADH (SIADH)
Causes contraction of the myoepithelial cells of the mammary alveoli & ducts and the ejection of milk.
Oxytocin
Stimulation of the nipple through suckling produces a neurohumoral reflex that causes secretion of.
Oxytocin
Affects the myometrium, as it increases both the frequency and the duration of action potentials during uterine contractions.
Oxytocin
Thyrotropes in the anterior pituitary produce… And its release is stimulated by…
TSH
Released by Thyrotropin-relasing hormone
Corticotropes in the anterior pituitary produce… And its release is stimulated by…
ACTH
Released by Corticotropin- releasing hormone
Somatotropes in the anterior pituitary produce… And its release is stimulated/inhibited by…
GH
Released by Growth hormone releasing hormone
Inhibited by Growth hormone- inhibiting hormone
Lactotropes in the anterior pituitary produce… And its release is stimulated/inhibited by…
Prolactin
Released by Prolactin-releasing factor
Inhibited by Prolactin-inhibiting factor
Gonadotropes in the anterior pituitary produce… And its release is stimulated by…
FSH, LH
Released by Gonadotropin releasing hormone
GHIH is also known as________.
somatostatin
Other actions of growth hormone are mediated indirectly through the production of____________ (or _____________) in the liver.
SOMATOMEDINS
Also called
INSULIN-LIKE GROWTH FACTORS [IGFs]
What are the effects of IGFs?
Stimulates the hypothalamus secretion of Somatostatin/GHIH, also inhibits the anterior pituitary from producing GH.
Growth Hormone Preparations
x-tropin e.g. Genotropin
Humatrope and Saizen
Blocks growth hormone receptors throughout the body and reduces blood levels of IGF-1
Pegvisomant (Somavert)
Name the Inhibitory factors of Prolactin Secretion
Dopamine
Bromocriptine (dopamine agonist)
Somatostatin
Prolactin (negative feedback)
Name the stimulatory factors of Prolactin Secretion
Pregnancy Breast-feeding sleep stress TRH Dopamine antagonist
Drugs for Hyperprolactinemia, maybe because of a prolactinoma
Cabergoline (Cabaser, others), Bromocriptine (Parlodel, others)
stimulates Leydig cells in the testes to synthesize and secrete testosterone
LH
stimulates Sertoli cells in the testes to secrete seminal fluid
FSH
During the first half of the menstrual cycle (follicular phase) and the midpoint, FSH and LH stimulate the ovaries to….
synthesize and secrete estradiol (the major type of estrogen)
During the second half of the menstrual cycle (luteal phase), FSH and LH stimulate the ovaries to
synthesize and secrete progesterone
These cells secrete calcitonin
C cells (parafollicular cells)
Thyroid hormones are derivatives of…
the amino acid tyrosine
Follicular cells synthesize __________
and dump into the colloid
TGB
with its numerous tyrosine
MIT + DIT = ?
T3
DIT + DIT = ?
T4
The Oxidation of I- to I2, the Organification of I2, and Coupling and colloid storage require the enzyme
THYROID PEROXIDASE
catalyzes the Deiodination of residual MIT
& DIT
thyroid deiodinase
TSH Actions
Stimulates TGB synthesis
Stimulates Na+/I- pump activity
Activates thyroid peroxidase
hypertrophy and hyperplasia of thyroid follicular cells
What are the three major thyroid hormone transport proteins?
thyroxine-binding globulin (TBG) [Don’t confuse with TGB]
thyroxine-binding pre-albumin (TBPA)
albumin
Synthetic T4 thyroid hormone preparations include:
Levothyroxine (T4) [Levothroid,
Levoxyl, Synthroid, Unithroid]
Liotrix (A mixture of T4 & T3 4:1)
[Thyrolar]
Synthetic T3 thyroid hormone preparations include:
Liothyronine (T3) [Cytomel]
Liotrix (A mixture of T4 & T3 4:1)
[Thyrolar]
is a term generally used to denote severe hypothyroidism.
Myxedema
anti-thyroid drugs
thioamides
inhibit thyroid peroxidase- catalyzed steps in the synthetic process
Methimazole and propylthiouracil (PTU)
