Pituitary and Gonads Flashcards
Major inhibitor of prolactin?
Causes of prolactin level increases?
Dopamine
Most common pituitary adenoma (70-80%); Pituitary stalk compression (blocks dompamine from reaching it)
Drugs; Macroprolactin high MW forms w/ symptoms
What is macroprolactin?
What is the prolactin level in patient with tumors?
High molecular weight form; 10% of elevated prolacting, needs chromatography or precipitation
Different reactions have different abilities to pick it up
Often high prolacting and symptoms
Tumorrs >200 ng/mL almost all, 100-200 consider tumors, <100 check for something else
Growth hormone overproduction leads to?
Under production?
How to measure GH excess?
What does insulin do?
Sigle best test?
Gigantism and acromegaly (adults)
Underproduction (pituitary dwarfism), few symptoms in adults
Basal levels not useful
Glucose inhibits GH; test hr after GGT load; FAILURE TO SUPPRESS IN TUMORS
IGF-1 best single test for dx and follow up
GH deficiency classically defined as?
What can be used to tx in kids?
GH not responding to 2 stimuli
IGF-1 (>5 yrs; <5 cannot detect low GH as it is baseline level); IGFBP-3
Hypopituitarism might affect what hormones?
GnRH is stead or pulsitile?
Some or all hormones: Prolactin maybe high, GH, Gonadotrophins lost early, TSH later, ACTH last; not specific order
GnRH: Pulsitile needed to release FSH (gammetes–make inhibin that negatively feeds back) and LH (sex steroids)
When does GnRH become pulsitile?
What happens if GnRH is continuous?
Puberty
Inhibits FSH and LH
In females what drops to cause LH surge?
What is prominent prior to ovulation?
After ovulation?
If no fetilizaiton what drops to cause menstration?
Test for adequate estrogen by?
Estrogen; LH surge then an FSH
Estrogen
Progesterone with small estrogen rise as well
Progesterone
Giving progesterone and then withdrawing to see if patient has bleeding
Techal cells under control of what hormone, make?
What does this product get converted into and where?
Theca cells; LH affected which makes Androstenedione which is converted in Granulosa cells (under FSH) to estradiol and in fat to estrone and testosterone
Adrenal makes what major androgen?
T/F testosterone is protein bound?
What time of the day is testoterone highest?
What is the LH level if testosterone is low?
What happens to SHBG as T falls?
DHEA-S
T; 5% free (66% bone to SHBG and 30% on albumin; can be active)
Morning; slowly declines during day and with aging or obesity
Tends to be in reference range
SHBG rises if T drops; free T not reliable (unless eq. dialysis)
What do you test to measure corpus luteum function?
In ovulating women what is most common estrogen, and in post menopausal women?
Most dominant in pregnancy?
Progesterone; must base on day of cycle
Ovulating: Estradiol from granulosa cells
Post menopausal: Estrone
Pregnancy: Estriol: placents
What is anti-Mullerian hormone?
What causes it to drop, marker for?
What disease is it high in?
Made in granulosa cells, inhibits excess response to FSH (granulosa cells); During development prevents mullerian ducts to develop so Wolfien ducts get made
Drops as follicles are lost; ovarian reserve
High in PCOS
In HCG testing serum assays detect, Urine Ab detects?
How often is doubling duirng 1st 12 weeks?
What is worry in ectopic pregnancy production?
Serum: Ab to beta subunit Urine: B-Core
Every 2 days
Abnormal forms might not be recognized by some assays
How to screen for ED?
After LH and FSH good?
Only 15-20% hormonal; screen free or total testosterone
If T abnormal then test prolactin
No stay normal in most cases
In women during menopause what happens to FSH and LH levels?
Which is the more reliable test?
First test for amenorrhea?
Does hirsuitism require low levels of androgens?
Then tned to gradulally rise before menopause;
FSH more reliable, AMH goes down
R/O pregnancy: then check prolactin, consider high androgens
NO; needs high levels and indicates androgen excess
Causes of Hirsutism?
Major androgen?
Major adenral androgen?
Ovarian androgen?
Virilization then think?
Abnormal androgen effect
Family hx: Often causes by 5-a-reductase causes high high levels of dihydrotestosterone at hair follicles
Adrenal: DHEA-S
Testosterone from peripheral conversion; or Leidig cell tumor
Virilization think TUMOR!
PCOS, can it cause hirsutism, LH:FSH ratio?
What is congential adrnal hyperplasia?
What backs up in 21-hydroxylase deficiencey?
11-hydroxylase deficency?
YES, >3:1
CAH: High steroid precursors:
17-OH progesterone with 21-hydroylase deficency (most common)
11-deoxycortisol with 11-hydroxylase deficency
In extra cellular fluid how does calcium exist, active form?
What makes calcitonin, what is procalcitonin measured for?
45-50% as ionized form (Ca2+): 50% bound to proteins mostly albumin
5-10% complexed with Phosphate and Bicard
Parafolicular C cells in thyroid: procalcitonin measured in spesis
What two hormones really regulate free calcium?
PTH responds to?
PTH (short term); Calcitriol (long term)
PTH: Responds to low free calcium and leaches 1% of free calcium from bone and causes kidney to excrete phosphate and bicarbonate (to free calcium); eventually causes bone reabsorption
PTH activates kidney Calcitriol (1,25 vit D) causes causes absorption of Ca and phosphate
What does FGF-23 respond to?
High in what disease?
High levels of phosphate: blocks phosphate reabsorption in kidney and Calcitriol production
Kidney disease; can cause cardiac dysfunction as it is a fibroblast producer
What are the two forms of Vit D?
Where are they made?
Vit D activation steps?
If you want to measure Vit D deficiency, measure?
Vit D2 (ergocalciferol) plants; D3 (cholecalciferol) skin from UV light
Both become 25-OH in liver; refects diet and production
Final form 1-alpha-OHase in kidney from PTH or low phosphate; low level=dietary deficiency or decreased sunlight
Vit D deficency: 25-OH-D
What Ch is PTH-RP on?
What is it required for?
Also made in what?
Why do we care?
Chr 12 vs PTH on 11
Fetal bone development; made in fetuses to get Ca2+ across placenta (PTH doesn’t)
Breast cells and in breast milk
Tumors make it!
What are some byproducts of osteoblasts activity?
Osteoclasts when breaking down bones make?
Alk phos, Osteoclalcin, Collagen propeptide
Acid phosphatse, H+, Hydroxyproline, Pyridium Crosslink, Telopeptides (collagen break down markers mostly)
Pitfall of total calcium measurement in hospitalized patients?
Things that inhibit?
Best practices to measure free calcium?
Changes in protein and complexes happen but test is insenstive to free calcium in hospitalized patients
Colorimetric assays inhibitied by chelators (EDTA), gadolinium (MRI agent) can affect dye binding but not to electrochemical methods
Free Ca: Handle like blood gas, pH changes rapidly, most appropriate in acute ill patients, can estimate in outpatients using albumin
1-25-OH D has how many -OH groups?
3 Common causes of Hypercalcemia?
Cholesterol nucleus with middle ring broken up; 25-OHD has 2 -OH groups, if 3 it is 1,25-OH D
Hemoconcentration, Primary hyperparathyroidism, Malignancy
What is primary hyperparathyroidism?
Is it stable?
Phosphate levels?
PTH levels?
Tx?
Common in outpatient; <12 mg/dL mild increase
Levels tend to be stable
Low to normal with high CL Cl/PO4 ratio >33
Increased or high normal
Adenomectomy and levels drop
What type of hypercalcemia is seen in malignancy, mild or severe?
Due to production of?
What lab may be low?
What autoimmune disease can cause high calcium?
What is FHH?
Severe >13 mg/dL
PTHrP (squamous, breast, renal); also bone mets (causes Ca2+ to increase)
PTH levels maybe undetectable!! ; PTHrP assays are available
Sarcoid!
Famialial high calcium and low in urine; asymptomatic
Causes of hypocalcemia?
Most common?
What other thing can be missing that causes hypocalcemia?
Renal failure and low albumin (both are 90%)
Hypomagnesemia
Malabsorption of vit D
Hypoparathyrodism or PTH resistance in sepsis, shock, and pancreatitis
What is secondary hyperparathyrodism?
Labs?
Bone Findings?
Chronic hypocalcemia
PTH much higher than primary; high phosphate when due to renal failure; may cause metastatic calcs in vessels
Severe bone disease
