Clinical Chemistry Unit 7

Where are the endocrine hormones secreted?

Bloodstream

 What are the characteristics of peptide hormones?

Unbroken chain of amino acids they are hydrophilic (water soluble), must first bind to membrane bound receptors

What two amino acids are the amine hormones derived from?

Tryptophan or tyrosine

Are steroid hormones, hydrophobic or hydrophilic? What do they require what to travel in the blood?

Hydrophobic, must be bound to carrier proteins. Can cross cellular membrane due to lipid content.

What is the function of a tropic hormone?

Stimulates another cell to release a message

What is the principal estrogen produced by the ovaries?

Estradiol

What hormone stimulates the secretion of TSH?

TRH (thyrotropin releasing hormone)

When there is a decrease in thyroid hormone production, what gland is stimulated to increase TSH production?

pituitary gland

What hormone regulates the serum calcium concentration?

Parathyroid hormone (PTH) 

What does the hormone insulin do?

Allows glucose to enter cells, only hormone that decreases blood glucose levels 

What hormone is secreted by the placenta? Used to detect pregnancy.

HCG

Glucose loading impairs the secretion of what hormone?

Growth hormone

What is a negative feedback loop? give an example.

negative feedback decreases the OG signal until it dissapears. Thyroid

What is a positive feedback loop? give an example.

amplified the signal until an endpoint is reached

Giving birth (oxytocin increasing contractions, making more oxytocin until baby is born)

What is diurnal variation?

Fluctuation in daily blood/urine analyte concentration 

What hormones are affected by diurnal variation?

cortisol and testosterone

What occurs to hormones when the carrier protein volume is decreased?

decreases protein bound hormone concentration

Which endocrine gland stimulates the secretion of pituitary hormones?

Hypothalamus

ACE inhibitors Falsely elevate what? It also interferes with what measurement? 

Elevates plasma renin activity, interferes with plasma aldosterone 

What is the most biologically active thyroid hormone?

T3

What is the synthesis of the thyroid hormone?

Iodine is the trace element thyroid hormone is made from.  

What two things does thyroid peroxidase catalyze a reaction of?

DIT and MIT

What are the TSH levels in primary hypothyroidism? What are the T4 levels?

Increased, decreased

What are the TSH levels in secondary hypothyroidism? What are the T4 levels?

decreased, decreased

What are the three types of hypothyroidism?

Primary (thyroid gland) secondary (pituitary) or tertiary (hypothalamic)

What are the expected lab results for hashimotos?

(primary hypothyroidism) low FT4, normal to high TSH

What are the expected lab results for graves disease?

(primary hyperthyroidism) low tsh, anti-TSHR, high FT4

What hormone is created by the hypothalamus and is stored in the posterior pituitary gland?

arginine vasopressin

What hormones are secreted from the posterior pituitary?

Oxytocin and arginine vasopressin

What are the tropic hormones of the pituitary?

TSH, LH, FSH, and ACTH 

What are the direct effectors of the pituitary gland?

Growth hormone (GH) and prolactin 

Which hormones are associated with acromegaly?

the cosecretion of prolactin

A growth hormone secreting-tumor in an adult may result in what condition?

Acromegaly

Diabetes insipidus can be caused by a deficiency of what?

Vasopressin

What is the common substrate for adrenal steroids?

Cholesterol

Major warning signs of adrenal disease include what?

abnormal blood pressure, abnormal electrolytes

Know the corresponding lab result for Addison’s disease?

cortisol:

sodium:

potassium:

Low cortisol, low sodium and high potassium

What test has the best diagnostic sensitivity for adrenal cortical hyperfunction?

Urine free cortisol collected over 24 hrs 

What can we measure in a 24-hr urine collection?

creatinine clearance, norepinephine, dopamine, cortisol

What is a normal dexamethasone suppression test result?

<1.8

How is the dexamethasone suppression test preformed?

Administering 1mg of dex between 11pm and midnight followed by 8am serum cortisol.  

potassium, acid–base status, urine dilution, and unexplained weight change are all warnings of what disease?

Adrenal disease

What hormones are secreted by the adrenal medulla? 

(catecholamines) Epinephrine and norepinephrine 

Phenylalanine is the amino acid needed for the biosynthesis of what hormones?

Norepinephrine and epinephrine

What screening lab test do we use to diagnose pheochromocytoma?

Plasma fractionated metanephrines

What hormone stimulates the testes to secrete androgens?

Luteinizing hormone (LH)

Which hormone directly stimulates testosterone secretion (Leydig cells)?

LH

What does progesterone do to the body at the time of ovulation?

Increases body temperature

Which hormone is deficient in a woman who has a luteal phase defect?

Progesterone

What hormones are elevated in menopause?

FSH and LH

What hormones are decreased in menopause?

estrogen

Which hormones serum level increases following ovulation and then abruptly falls to low concentrations prior to onset of menstruation?

Progesterone

What analytes are regulated by the PTH?

Calcium and phosphorous

What is the name of the active form of Vitamin D?

1,25(OH)2D

What are the organs involved in the maintenance of calcium?

bone kidneys and GI tract

In secondary hyperparathyroidism, what is the PTH and the Calcium levels?

Elevated PTH with normal-low calcium

Which type of hyperparathyroidism is associated with renal failure?

Secondary

PTH-related protein increase is associated with what condition?

Hypercalcemia of malignancy (Cancer)

a patient has an increased serum calcium level and a decreased serum phosphorus level. the PTH level is also increased these results correlate with which disorder?

Primary hyperparathyroidism

Adenoma in one of the parathyroid glands is the most common cause of what condition?

Primary hyperparathyroidism

Procalcitonin test is used for what in the hospital?

sepsis bundle as quality indicator

What tests would a dr order to diagnose medullary thyroid carcinoma?

calcitonin

What is the location of the steroid hormone recpetors?

the nucleus

what endocrine glands do the primary secondary and tertiary disorders correspond to?

target gland, pituitary, hypothalamus

what are the corresponding lab results for addisons disease?

low sodium high potassium increased calcium low PTH

when should diurnal hormone specimens be drawn?

8am and 8pm

what is the typical suspect when a patient has hypertension that is due to the endocrine system? what is the patients hormonal concentration typically?

Adrenal gland, hormone overproduction

what is the overall effect of PTH release?

Increase bone resorption of calcium

what are the results of primary hyperparathyroidism NEW

Increased serum calcium, decreased serum phosphorous, increased PTH

in secondary hyperparathyroidism what are the PTH and the calcium levels? NEW

Increased PTH and decreased calcium