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Published byJasmine Ariel Sharp Modified over 9 years ago
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PREGNANCY PROTEINS Early pregnancy factor (EPF) Placental proteins: –pituitary-like hormones: hCG, hPL, ACTH, hCT –hypothalamic-like hormones: GnRH, CRH, TRH, SRIF –growth factors: inhibin, activin, IGFs, EGF –other peptides: SP-1, PAPP-A, PP-5 Decidual proteins: PRL, relaxin, IGFBP, PP-14 Fetal proteins: AFP
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HUMAN PLACENTA
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Early pregnancy factor (EPF) immunosupressive protein produced by maternal ovaries stimulated by PAF earliest known indicator of fertilization (48hr) maximum production 0- 4 weeks then function: –prevents rejection of an embryo (binds to lymphocytes) –growth factor (?) clinical applications : to be evaluated
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HUMAN CHORIONIC GONADOTROPIN (hCG) glycoprotein hormone, two chains –alpha-subunit (chromosome 6) : identical –beta-subunit (chromosome 19) : unique activity and specificity trophoblastic tissue (syncytiotrophoblast) –normal placenta (also multiple placenta) –gestational trophoblastic disease (hydatiform mole and choriocarcinoma; x 3-100) –ectopic pregnancy
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hCG levels during pregnancy
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HUMAN CHORIONIC GONADOTROPIN (hCG) control of secretion: placental GnRH secreted by cytotrophoblast ( activin, inhibin) normal pattern of secretion : – 8 days post conception, dbl time 2-3 days –peak value 8-10 wk. of gestation ( 120,000 IU/L) – and reach plateau 20,000 IU/L at 18-20 wk. of gestation – in multiple pregnancy –at 1,000-1,500 IU/L intrauterine gestation visible with TVG ultrasound
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HUMAN CHORIONIC GONADOTROPIN (hCG) determination: –biologic assays –immunologic: radioimmunoassay (RIA, sensitivity 5mIU/ml) immunoradiometric assay (IRMA, sensitivity 150mIU/ml) ELISA (sensitivity 25-150mIU/ml) fluoroimmunoassay (sensitivity 1mIU/ml) latex agglutination inhibition tests (urine) radioreceptor assay high sensitivity pregnancy tests (<1mIU/ml) - sometimes false positive because of endogenous pituitary hCG
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maintains corpus luteum stimulates: –progesterone production by the corpus luteum –Leydig cells of male fetus to produce testosterone (?) –fetal adrenal steroidogenesis immunosupressive (lymphocyte modulator) thyrotropic activity induction of ovulation FUNCTION OF hCG
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HUMAN PLACENTAL LACTOGEN (hPL) HUMAN SOMMATOMAMMOTROPHIN (hCS) single chain polypeptide produced 3 wk. post conception; detected in serum 5-6 wk. post conception highest levels III trimester, disappears after delivery production proportional to placental mass determination: RIA
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Role of hPL during pregnancy
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HUMAN PLACENTAL LACTOGEN (hPL) HUMAN SOMMATOMAMMOTROPHIN (hCS) Growth hormone (GH and PRL-like effects) : –induces lypolysis, plasma FFA –inhibits glucose uptake and gluconeogenesis, glucose intolerance –insulinogenic effect ( insulin) –hyperinsulinemia – plasma IGF-I
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ADRENOCORTICOTROPIN (ACTH) structurally similar to pituitary ACTH circulating maternal levels hypercortisolism CORTICOTROPIN RELEASING HORMONE (CRH) produced in cytotrophoblast (max. at term) stimulates placental ACTH release circulating maternal levels
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DECIDUAL PROLACTIN (PRL) similar to pituitary prolactin regulates fluid and electrolyte flux through fetal membranes secreted independently of fetal/maternal dopaminergic control ALSO maternal and fetal pituitary PRL maternal serum PRL (100-200ng/ml) AF PRL until 20wk. (1000ng/ml) then
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PLACENTAL PROTEIN 14 (PP14) immunosupresive peptide secreted in decidualized endometrium circulating marker of decidual growth ALPHA-FETALPROTEIN (AFP) synthesized in YS, GI and fetal liver osmoregulator of fetal intravascular volume AFAFP and MSAFP in neural tube defects MSAFP in pregnancies with Down syndrome
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Estrogens: –estradiol –estriol –estrone Progestogens: –progesterone –17alpha-OHprogesterone Adrenocorticoids: –cortisol PREGNANCY STEROIDS
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ESTRIOL 1000 x more than in non pregnant state 90% of all estrogens in pregnancy exclusively produced by placenta (conversion of 16alpha-DHEA-S) - only living fetus detectable at 9 th wk. (0,05ng/ml) ; at term (30ng/ml) ESTRADIOL / ESTRONE produced by maternal sources (estradiol-ovaries: 5-6 wk.; estrone-ovaries, adrenal: 4-6wk.), gradually placenta, after I trimester major source (conversion of circulating DHEA-S) after conception range 5-30ng/ml
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MATERNAL PLASMA UNCONJUGATED ESTROGENS Estradiol Estriol Estrone
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extremly low levels or no estriol: –fetal demise, anencephaly –CAH –placental sulfatase deficiency –hydatidiform moles decline in estriol production or failure to rise: –maternal renal disease, PIH, preeclampsia or eclampsia –IUGR large quantities: –multiple pregnancy –Rh isoimmunisationESTRIOL
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ESTROGENS - HORMONAL FUNCTION augment uterine blood flow placental steroidogenesis: regulation of progesterone synthesis parturition: –ripen the cervix –initiate uterine activity –augment established labor – sensitivity of myometrium to oxytocin
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PROGESTERONE production during pregnancy: –corpus luteum (only source till 6 th wk.) –placenta (6 th wk. -> 12 th wk. -> parturition ) luteoplacental shift: 7-8 th wk of pregnancy production independent of fetus conception cycle: sustained slow rise early pregnancy: 10-35ng/ml, 100mg/day at term: max. 100-300ng/ml, 250mg/day
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MATERNAL PLASMA PROGESTERONE
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modulates tubal motility (preimplantation conceptus) inhibits maternal-fetal tissue rejection antagonizes estrogen-augmented uterine blood flow induces uterine relaxation (stabilization of lysosomal membranes and inhibition of PG production) PROGESTERONE - HORMONAL FUNCTION
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Steroidogenesis in fetus & placenta
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OVARIAN STEROIDOGENESIS
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