Tietze Chapter 5 (Endocrine)

Adrenal Medulla

The 24-hour urinary excretion of epinephrine, norepinephrine, and vanillylmandelic acid (VMA) is used to assess the function of the —

Triiodothyronine uptake T3U test

-is an in vitro test that indirectly estimates the amount of thyroid-binding globulin in the serum.

Catecholamines

The adrenal medulla secretes —

• 0-20 mcg/24 hr

• Urine

Adrenal Medulla and Catechol Secretions

• Epinephrine RR

• 15-80 mcg/24hr

• Urine

Adrenal Medulla and Catechol Secretions

• Norepinephrine RR

• 0.15-1.2 mg/24hr

• Urine

Adrenal Medulla and Catechol Secretions

• Vanillylmandeic Acid (VMA)

Adrenal cortex

The — secretes mineralocorticoids, glucocorticoids, and androgens.

• 2-9 ng/dL

• Serum, Plasma

Adrenal Cortex

• Aldosterone RR

• 0-10 mcg/dL

• Plasma

Adrenal Cortex

• Cortisol RR

• 0.5-1.6 ng/ml/hr

• Plasma

Adrenal Cortex

• Renin RR

• Aldosterone

• Renin

What adrenal cortex tests should have recumbent and normal salt diet

• 8 am fasting

At what time does fasting start for cortisol test

6 hours

How long should renin levels be monitored

Dexamethasone

— suppresses ACTH secretion.

• 8 AM

• 11 PM

• 8 AM

A baseline — plasma cortisol level is obtained and then 1 mg of dexamethasone is administered orally at — Normally, cortisol production is suppressed, and the — plasma cortisol level obtained the next day is low

Insulin tolerance Test

In thIS test, insulin (0.05 to 0.1 units/kg) is administered intravenously. Serial blood samples are obtained for 90 minutes. ACTH is released when the blood glucose level falls to less than 40 mg/dL.

Metyrapone

It inhibits the final step in cortisol synthesis.

• Plasm Cortisone

• Plasma and Urine 11-deoxycortisol (Compound S)

For the metyrapone test, 500 to 750 mg of metyrapone is administered orally every 4 hours for 24 hours, and plasma samples are collected.

• A normal response is a decrease in — and an elevation in —

Amylase

Although not specific for pancreatitis, serum — is easier to measure than is lipase and is used as a common screening and monitoring parameter for acute pancreatitis.

Chronic Pancreatitis

In —, however, the pancreas may be burned out and unable to secrete amylase.

C-peptide

It is an inactive peptide chain released from beta cells in equimolar amounts with insulin and is found in the serum in about a 5:1 to 15:1 ratio with insulin.

— level is sometimes used to assess pancreatic function.

Glucose

Serum — concentrations are used to assess pancreatic function and the response to insulin replacement therapy.

10-14 Hours

For the fasting serum glucose test the serum sample is obtained after — of fasting. The fasting serum glucose level is usually obtained before breakfast after an overnight fast.

Glucose tolerance test

this is used to diagnose diabetes mellitus and gestational diabetes.

• Patients fast for 10 to 16 hours before the test and are then given approximately 75 g of glucose

• <200 mg/dL

• <140 mg/dL

For Glucose Tolerance Test

• Glucose level at 30,60,90 minutes:

• At 2 hours:

Glycosylated Hemoglobin

It is formed when hemoglobin is irreversibly glycosylated after exposure to high glucose levels. It's levels assess

• long-term control of hyperglycemia with insulin therapy

• differentiate factitious hyperglycemia from diabetes.

Lipase

It is a specific marker for acute pancreatic disease. Increases in this parallel increases in serum amylase.

• 60-180 units/L

• Serum

Pancreas

• Amylase RR

• 75-115 mg/dL

• Plasma

Pancreas

• Glucose (fasting) RR

• 2-20 microunits/mL

• Plasma, serum

Pancreas

• Insulin (fasting) RR

• 0-160 units/dL

• Serum

Pancreas

• Lipase RR

Calcium

High serum — levels suppress PTH secretion

• PTH

• Calcium

• Phosphorus

Parathyroid gland function is tested by measuring the serum concentrations of —

Parathyroid Hormone (PTH)

The serum concentration of — is useful in differentiating between hypercalcemia resulting from hyperparathyroidism and hypercalcemia resulting from other causes.

• 9.0-10.5 mg/dL

• Serum

Parathyroid

• Calcium RR

• 10-60 pg/mL

• Plasma, serum

Parathyroid

• PTH RR

• 3.0-4.5 mg/dL

• Serum

Parathyroid

• Phosphorus RR

Adrenal cortisol production

ACTH stimulates —n. A baseline plasma cortisol level is obtained and then 250 mcg of cosyntropin is injected intravenously. Normally, plasma cortisol levels peak in 30 to 60 minutes.

• 6-76 pg/mL

• Plasma

Pituitary

• ACTH RR

• 0.5-17 ng/mL

• Serum

Pituitary

• Growth hormone (fasting) RR

• 0-20 ng/mL

• Serum

Pituitary

• Prolactin Female RR

• 0-15 ng/dL

• Serum

Pituitary

• Prolactin Male RR

Free thyroxine index (FT4I)

It is the product of the measured T4 level and the triiodothyronine uptake (T3U).

• Hypothyroidism

• Hyperthyroidism

FT4I is decreased in — and increased in —.

Thyroid-stimulating hormone (thyrotropin).

It used to differentiate between thyroid-related hypothyroidism and pituitaryrelated hypothyroidism. Levels is elevated in thyroidal hypothyroidism and markedly decreased in pituitary hypothyroidism.

Thyroid uptake of radioiodine

Radioactive iodine (iodine I 123 or iodine I 131) is administered orally, and the radioactivity over the thyroid gland is measured at various intervals. What is this called

10% to 35%.

The normal radioactive iodine uptake (RAIU) is about

Thyrotropin-releasing hormone (TRH)

It stimulates the pituitary to release TSH. Injection of synthetic It normally causes an increase in TSH in about 30 minutes.

• 4.6-11.2

• Serum

Thyroid

• FT4I RR

• 0.5-4.7 microunits/mL

• Serum

Thyroid

• TSH RR

• 60-181 ng/dL

• Serum

Thyroid

• T3 RR

• 4.5-10.9 mcg/dL

• Serum

Thyroid

• T4 RR

• <20-443 pg/mL

• Serum, Plasma

Gonad - Estradiol

• Premenopausal female RR

• <59 pg/mL

• Serum, Plasma

Gonad - Estradiol

• Postmenopausal female RR

• <20 pg/mL

• Serum, plasma

Gonad - Estradiol

• Male RR

• 6-86 ng/dL

• Serum

Gonad - Testosterone

• Female RR

• 270-1070 ng/dL

• Serum

Gonad - Testosterone

• Male RR