Clinical Chemistries: Endocrine Assays Flashcards
What do the hypothalamus and pituitary regulate?
Growth
Development
Metabolism
Homeostasis
What controls the pituitary gland by releasing and inhibiting hormones?
The Hypothalamus
What does the hypothalamus produce?
ADH and oxytocin
What is considered the Master Gland?
The pituitary gland
The pituitary gland is made of what two lobes?
Anterior Pituitary
Posterior Pituitary
What are the seven hormones released by the Anterior Pituitary Hormones?
- Thyroid Stimulating Hormone (TSH)
- Adrenocorticotropic Hormone (ACTH)
- Growth Hormone
- Follicle Stimulating Hormone
- Luteinizing Hormone
- Prolactin
- Melanocyte-stimulating Hormone
What are the seven hormones stimulated by?
Endocrine signals from hypothalamus
Adrenal Cortex
Glucocorticoids
Mineralocorticoids
Sex Hormones
Adrenal Medulla
Epinephrine and Norepinephrine
What happens when the animal is stressed?
The brain triggers the hypothalamus to secrete a corticotropin-releasing factor (CRF)
What does CRF trigger the secretion of?
Adrenocorticotropic hormone (ACTH)
Cushing disease (hyperadrenocorticism)
Brain or pituitary tumors and overuse of glucocorticoids may cause excessive cortisol release
What are the symptoms of Cushing’s disease?
Pot-belly Symmetrical hair loss PU/PD polyphagia Lethargy Panting Skin disease UTIs
Addison Disease (Hypoadrenocorticism)
Decrease in cortisol
Cortex atrophies
What are the symptoms of Addison’s Disease?
Vomiting and Diarrhea Hypoglycemia Muscle Weakness Dehydration Bradycardia
What is used in animals with suspected hypoadrenocorticism or hyperadrenocorticism?
ACTH Stimulation Test
What does the ACT Stimulation test evaluate?
The degree of adrenal gland response to administration of exogenous ACTH
How accurate are the ACTH stimulation screening tests in dogs and cats?
80% in dogs
50% in cats
Low-dose Dexamethasone Suppression Test
Confirms or replaces ACTH response test for hyperadrenocorticism
High-dose Dexamethasone Suppression Test
Differentiates pituitary from adrenal causes
What test is only suitable for cats?
High-dose dexamethasone suppression test
What test differentiate between pituitary-dependent and primary hyperadrenocorticism?
Corticotropin-Releasing Hormone Stimulation
What should not be elevated after the CRH test?
Plasma cortisol concentrations and ACTH
In what disease will you see an increase in CRH?
Adrenal-dependent Cushing disease
How do you do a corticotropin-releasing hormone stimulation test?
Obtain a baseline sample
Administer 1mg/kg corticotropin-releasing hormone (CRH)
Sample again at 15 and 30 minutes
What does the thyroid gland secrete and then is converted to T3 and T4?
Thyroglobulin
Canine Hypothyroidism
Decreased production of thyroid hormones
What is the primary cause of hypothyroidism?
Autoimmune condition damaged thyroid which leads to decreased thyroxine
What are the symptoms of hypothyroidism?
Lethargy
Obesity
Heat Seeking behavior
Skin disorders
How do you treat hypothyroidism?
Thyroid Supplement
Feline Hyperthyroidism
The most common endocrine disease of older cats
What causes hyperthyroidism?
A benign thyroid tumor that secretes increased T3 and T4
What are the symptoms of hyperthyroidism?
Weight loss Increased appetite Rapid heart rate Poor hair coat Vomiting Diarrhea Muscle weakness
What is the treatment for hyperthyroidism?
Methimazole
Surgery
Radiation therapy
Other miscellaneous Test: Growth hormone
Diagnosis acromegaly or gigantism
Other miscellaneous tests: Malassimilation
Maldigestive (pancreas, digestive enzymes)
Malabsorptive (intestinal)
Other miscellaneous tests: Malassimilation four more tests
Monosaccharide
d-xylose absorption tests
Serum folate
Cobalamin levels
Other miscellaneous Tests: Occult Blood
GI ulcers, neoplasia, parasitism
What can the animals not eat before doing an occult blood test?
Eat meat three days before the test
What tests the quality and concentration of hyaluronic acid in synovial fluid?
Mucin Clot Test
How do you perform a Mucin Clot Test?
Arthrocentesis
What do you mix the synovial fluid with?
Acetic Acid or vinegar
What does the Mucin Clot measure?
The clot quality
How do you perform the Mucin Clot test?
Mix gently and allow to stand for one hour
Grade the clot quality
Good clot
Large, compact, ropy
Fair clot
Soft clot, with slightly turbid solution
Fair to Poor clot
A friable clot in a cloudy solution
Poor clot
No clot but large flecks of turbid solution
