Endocrine ADH Oxytocin (Welch) Flashcards
How do endocrine glands secrete their products?
Release hormones into circulation to exert effects distant from site of excretion
Hypothalamic hormones target what tissue?
Pituitary
Anterior Pituitary hormones target what tissue?
Thyroid, ovary, testis, adrenal cortex
What are the 2 hormone exceptions to the hormones and targets listed above?
Growth hormones and thyroid hormones affect most tissues
What are 3 physiologic functions of endocrine system?
- Homeostasis
- Growth to adulthood
- Pubertal changes for body development
The endocrine systems has what type of response: slow or quick?
Slow, prolonged
What are some examples of nonhormonal control of some body hormones?
- Blood glucose controls insulin in Beta cells and glucagon in alpha cells of pancreas
- Blood calcium controls parathyroid hormones and calcitonin from thyroid and parathyroid glands
What are 2 posterior Pituitary Hormones?
- ADH
2. Oxytocin
Where are the 2 posterior Pituitary Hormones ADH and Oxytocin synthesized?
Hypothalamus
Do the 2 posterior pituitary hormones ADH and oxytocin exert control on other hormones?
No
Regulatory hormones do what?
Regulate release of other hormones
How and where are the regulatory hormones released?
Hypothalamus activates the regulatory hormones to portal system, carrying the hormones to the anterior pituitary where they stimulate the release of a specific anterior pituitary hormone
What are 2 posterior pituitary hormones ADH and oxytocin are synthesized where and stored where?
Synthesized in neuronal cell bodies (supraoptic nuclei for ADH and paraventricular nuclei for oxytocin) transported down axons to store in Posterior pituitary
What are 2 ways to control hormone release, with respect to anterior pituitary?
- Releasing hormones + Negative feedback
2. Releasing hormones + inhibiting hormone
Are the 2 posterior pituitary hormones ADH and oxytocin under hormonal control or negative feedback control?
No
Are the 2 posterior pituitary hormones ADH and oxytocin under hormonal control or negative feedback control?
No
What controls the release of ADH from its storage in the posterior pituitary?
Water osmolarity
What is the most prominent effect of this hormone type is regulation of synthesis and release of pituitary hormones?
Regulatory hormones
Are regulatory hormones large or small polypeptides?
Small polypeptides
What are 4 general characteristics of regulatory hormones?
- Small polypeptides
- Not active orally
- Short acting when given IV
- Synthetic derivatives prepared relatively easily
What is a short loop versus a long loop negative feedback?
- Short loop occurs when anterior pituitary hormone release inhibits the hypothalamic releasing hormone
- Long loop occurs when hormone released from peripheral gland inhibits the hypothalamic releasing hormone
What are 3 causes of anterior hypopituitarism in adults?
- Sheehan’s syndrome
- Tumor
- Hypohysectomy due to cancer treatment or diabetes mellitus
What will atrophy in hypopituitarism in adults?
Atrophy of glands (decreased FSH)
Will the metabolic rate increase or decrease in adult hyperpituitarism?
Decrease due to decreased TSH
Will adult hypopituitarism cause hyperglycemia or hypoglycemia and why?
Hypoglycemic caused by increased sensitivity to insulin by GH
Will lactation be affected in adult hypopituitarism?
Yes, decreased prolactin
Will a hypotuitary adult have increased or decreased libido?
Decreased due to decreased LH and FSH
Will hypopituitary adult be able to respond well to stress?
No because of decreased ACTH
What will occur if the pituitary does not develop during embryogenesis?
Juvenile hypopituitarism
What is the stature of juvenile hypopituitarism?
Dwarf
Will juvenile hypopituitarism have normal or decreased longevity?
Normal
Will juvenile hypopituitarism have any sexual development?
No
What peripheral glands will be hypoactive in juvenile hypopituitarism?
Thyroid and adrenal glands
What replacement therapy can be done in hypopituitarism?
Give glucocorticoids, thyroid and sex hormones
What hormones can replacement therapy not replace?
- GH
- MSH
- Prolactin
A pituitary tumor will cause what?
Hyperpituitarism
What are 7 consequences of Hyperpituitarism?
- Gigantism
- Acromegaly
- Goiter
- Enlarged adrenal cortex
- Precocious sexual development
- Cushing’s syndrome
- Occasional lactation
What is the treatment for hyperpituitarism?
Surgical removal of tumor
What type of blood osmolarity stimulates release of Vasopressin/Antidiuretic hormone (ADH) from the posterior pituitary?
Hyperosmolarity
What are a neurotransmitter and a drug that can each cause the release of ADH from posterior pituitary?
- ACh
2. Physostigmine
Nicotine increases or decreases ADH?
Increases
Alcohol increases or decreases ADH?
Decreases
What are 3 receptors ADH acts on?
V1a, V2, V1b
What occurs when ADH binds to the renal V2 receptor?
Renal tubular reabsorption of water increases, which decreases the volume of urine output
Is the urine excreted when ADH is bound to the renal V2 receptors hypotonic or hypertonic?
Hypertonic
What occurs when ADH binds to the V1a receptors in smooth muscle?
Causes contraction of all smooth muscle of vasculature, increasing BP and decreasing HR
What is the ADH V2 receptor location?
Kidneys
What is the ADH V1a receptor location?
Vascular smooth muscle
ADH V1a receptor binding causes an increase in which due to vasoconstriction: increased BP or increased HR?
increased BP (it actually causes a DEcreased HR)
With Nephrogenic ADH unresponsiveness, the kidney tubules will not reabsorb water, causing what?
Diabetes insipidus
Nephrogenic Diabetes insipidus is most common in what demographic?
infant males
Treatment for Nephrogenic Diabetes insipidus?
Water replacement to prevent dehydration
Which type of diabetes Insipidus can be caused by head injury, hypothalamic and pituitary tumors, cerebral aneurysms, CNS ischemia, idiopathic or familial where there is a deficiency of ADH?
Neurogenic diabetes insipidus
What are symptoms of both Neurogenic or Nephrogenic Diabetes Insipidus?
- Excessive quantities of very dilute urine
2. Excessive thirst
Which Diabetes insipidus is the only one that can be treated by giving supplemental ADH?
Neurogenic
What are 2 ADH replacement drugs, but are short duration, injected, and antidiurectic and vasopressive?
1 PItuitrin
2. PItressin
What is an analog of ADH that is a better antidiuretic (more V2 action) than pressor activity (less V1 action)?
Desmopressin (DDAVP)
Is Desmopressin (DDAVP) short or long acting?
Long acting
How is Desmopressin (DDAVP) administered?
Intranasally
What does desmopressin do for certain bleeding disorders?
Increase Factor VIII in Von Willebrand’s disease or Hemophilia A
When are Pituitrin and Pitressin usually used?
Emergencies
ADH can be used to diagnose what?
Concentrating potential of kidney
ADH + Neostigmine has been used to treat what?
Intestinal distention
Is ADH to be used as a pressor agent?
No
What are 5 side effects of ADH administration?
- Increased intestinal activity (need to defecate)
- Nausea Belching Cramps
- Problems in angina patient as less blood gets to the heart
What childhood problem can Desmopressin be used for?
Nocturia (bed wetting)
What does ADH cause at the V2 receptor in the kidney?
G-coupled protein receptor triggering protein kinase A which inserts an aquaporin into the membrane
Both ADH and oxytocin are how many amino acids?
9
What are 3 stimuli for Oxytocin release from posterior pituitary?
- Parturation
- Suckling
- Sexual intercourse
What does oxytocin do to the uterus?
Causes rhythmic contractions
What does oxytocin effect on the uterus depend on?
- Uterine sensitivity
2. Oxytocin dose
When is the uterus more sensitive to oxytocin, full term or first trimester?
Full term
What hormone antagonizes oxytocin?
Progesterone
If estrogens are low, is oxytocin more or less effective?
Less effective
Why is progesterone level in first and second term important for pregnancy?
If none or low progesterone, oxytocine will have more effect on the uterus, which could lead to a miscarriage
What is the difference between the contraction induced by Oxytocin versus those done by the Ergot herb?
Oxytocin increases the force and frequency of the uterine contractions while maintaining a basal tone that keeps the baby safe. Ergots increase the force and frequency of the uterine contractions but also increases the resting tone, which will endanger the baby
At what part of delivery would Ergots be indicated?
Can be used to control hemorrhage after birth
What does oxytocin do on the mammary gland?
Contracts smooth m. causing milk ejection
Does oxytocin have an ADH-like effect in the Kidney?
Yes but it is weak. High dose can cause water intoxication.
Does oxytocin have any cardiovascular effect?
Yes, marked transient vasodilation causing a decrease in BP with a compensatory increase in HR
What are 3 reasons oxytocin is good for induction of labor?
- Increased frequency of contraction
- Increase force of contraction
- Little effect on resting tone of uterus
What is the name of the oxytocin used for labor induction?
Pitocin
What is the name of the oxytocin nasal spray used for relief of engorged breasts during nursing (which is seldom successful)?
Syntocin
What are 2 classes of hormones?
- Water soluble
2. Lipid soluble
What are 2 water soluble hormones?
- Catecholamines (Epi, NE)
2. Peptide / protein hormones
What are some examples of lipid soluble hormones?
- Thyroid hormone
- Steroid hormone
- Vitamin D3
Where are lipid soluble hormone receptors located and how do they exert their effects?
Inside the cell and affect DNA and RNA synthesis
Where are water soluble hormone receptors located and how do they exert their effects?
Outside of cell coupled to a second messenger
What is the term for lipid soluble hormones that bind to receptors within the cell (this complex then binds with what part of the DNA sequence and where is the DNA sequence located within the gene)?
Response element located in regulatory region of genes
?What is the character of responses elicited by lipid soluble hormones?
Slow because they require transcription and translation to evoke physiological response