Hormones: HGC, LH, FSH, Prolactin Flashcards
Intact Human Chorionic Gonadotropin (hCG)
(production, function, structure)
Production:
- syncytiotrophoblast cells in pregnancy
- hydatidiform moles
Function:
- Advance uterine angiogensis
- Promote progesterone production in corpus leuteal cells
Structure: ~36 ku unit c subunits
- Alpha subunits are similar to other structures
- hCG-H
- Pituitary hCG
- LH
- FSH
- TSH
- Beta subunits are more specific
- similar to LH
- different from other molecules
- *Significance - there is specificity variation and some false positives *
Hyperglycosylated hCG (hCG-H)
(structure, production, function, clinical use)
Production: Cytotrophoblast cells of placenta. No hCG involvement in production
Stucture: hCG varient - autocrine or cytokine but not a hormone
Function: promotes growth, invasion, and malignancy
Clinical use:
- Accurate marker of invasive mole and invasive choriocarinoma
- Dx/managment of gestational trophoblastic disease
Note: it may cause false results in other hCG tests, including beta hCG
Free Beta Subunit of hCG
(origin, structure, production, function)
Origin: beta subunit of hCG c triantennary N-linked and O-linked hexosamines
Structure:
- Autocrine or cytokine
- Simply the beta subunit of hCG, independently cleaved
Production: most GYN malignancies, moles, non-trophoblastic malignancies
- 68% ovarian malignancies
- 51% endometiral malignancies
- 46% cervical malignancies
Function: Decrease prognosis in GYn cancers
- Block cancer cell apoptosis
- Promotes malignancy growth
Pituitary hCG
(structure, function)
Structure: Same aa structure as regular hCG but is a sulfated varient of hCG (instead of sialylated oligosaccharide)
Function: Functionally similar to LH when secreted in low levels during menstual cycle
Clinical Uses, hCG Tests
Only FDA approved pregnancy dx assay
- Workup c transvaginal US:
- Suspected ectopic pregnancy
- Serial hCG testing
- Tumor marker
- Maternal serum screening for fetal aneuploides (trisomy 21) in the quad test:
- Tests
- Alpha fetoprotein
- Estriol
- Inhibin A
- hCG
- Tests
Diseases detected c hCG assay
(3 categories, 1 c 2 specifics)
- Gestational trophoblastic disease
- Hydatidiform moles
- Trophoblastic malignancy
- placental site trophoblastic tumors (cytotrophoblast cells arising from placental implantation site)
- Choriocarcinoma (both cytotrophoblastic and syncytiotrophoblastic elements)
- Non-gestational malignancy
- Testicular cancer
Total Beta-hCG Assays
(2 assays, clinical use)
Assay Parameters:
- Intact hCG
- Free beta hCG subunits
Clinical Use: Tumor marker
Total beta-hCG assay may be ideal becasue cancer pts produce significant amts of free beta sub unit
Interpretation, Beta-hCG
- Consider gestational week
- Different assays have different sensitivities. Listed below from least → most sensitive
- Urine home pregnancy test kit
- Urine qualitative hCG test in lab
- Serum quantitative hCG test in lab
- Serum quantitative beta-hCG test in lab
High Dose Hook Effect
hCG assay limitation - the hCG concentration is so high that it exceeds the optimum performance of the assay and usually yields a falsely low result
Variet Hook Effect
hCG assay limitation - Apart from cancer, concentrations for in-tact hCG will exceed measurable amounts at 5 weeks gestation
*Check with textbook on this *
hCG assays may detect
(6 compounds)
- hCG
- hCG-beta
- Nicked hCG
- Hyperglycosylated hCG (hCG-H)
- Hyperglycosylated hCG-beta
- hCG and hCG-beta missing the C-terminal peptide
Normal Physiology, LH (Lutropin) and FSH
- Hypthalamus secretes gonadotropin-releasing hormone (GnRH)
- GnRH stimulates anterior pituitary secretion of LH and FSH
- LH binds to Leydig cell receptors to enhance cholesterol → testosterone conversion
- FSH activates semineferous tubules fro sperm production
FSH/LH structures
Each consist of two subunits. They share the alpha subunit and differe c teh beta subunit. This **confers their functional specificity **
LH Functions
Male - induce testosterone prdcn in Leydig cells
Female - regulate menstrual cycle
Reproductive Hormone Changes in Disease
(2 standpoints)
- Amount - deficiency vs excess
- Origin - primary (gonadal) or secondary (pituitary)
- Primary - gonadal steroids and pituitary gonadotropins are inversely related
- Secondary - gonadal steroids and pituitary gonadotropins are directly related
LH/FSH Differentials
(11, 5/4/2 specifics)
Increased
- Gonadal failure (Turnur Syndrome)
- Klinefelter syndrome
- Polycystic ovaries
- Preconscious puberty
- Pituitary edema
Decreased
- Pituiatry failure
- Hypthalamic failure
- Anorexia nervosa
- Stress
Other
- Evaluate infertility
- Dx menopause - initiate hormone replacement thearpy
False elevations, LH/FSH Assays
(3)
- hCG and TSH similar alpha/beta subunits
- Patients c hCG-producing tumors and hypothyroidism
- Several drugs
Prolactin
(structure, production, function)
Structure: polypeptide, main circulating form is nonglycosylated monomer
Function: initiate/maintain milk prdctn
Origin: pituitary lactotroph production
First Response Female Fertility Test
Home urinalysis that detects **FSH ** in order to evaluate ovarian reseve (egg quantity and quality) - indicating ability to get pregnant
Prolactin Secretion
Quality - pulsitile c short 1/2 life (draw multiple samples @ 30 min intervals when assessing for hyperprolactinemia)
Elevations - sleep and early morning hours
Differential, Hyperprolactinemia
(4)
- **Pituitary dysfunction **or pregnancy/lactation
- Most common pituitary hormone hyper-secretion syndrome in both males and females
- Pituitary apoplexy (Sheehan syndrome) - females who severely hemorrhage post obstetric delivery and experience circulatory collapse, bleeding into pituitary gland (apolexy) and infarct it
- Sex specific
- Female - asst c amenorrhea and/or galactorrhea
- Medication side effects
- Phenothiazine
- OCP
- Opiates
- Estrogens
- Stress
False Results, Prolactin
(2)
- Low - assay artifacts (hook effect) requiring sample dilution
- High - aggrevated forms of circulating PRL, which are biologically inactive (ex - macroprolactinemia)
First Response, Ovulation Test
Detects your LH surge
