overview of the placental hormones

3. At 6-8 weeks there is
transfer of functions of corpus
luteum to the placenta-which
acts temporarily as a new
endocrine organ or powerhouse
of hormone production.

4. Protein hormones
Steroid hormones

5. HYPOTHALAMIC- CYTOCHEMICAL
LIKE(RELEASING) ORIGINE
HORMONES
Corticotrophin releasing Cytotrophoblast
(CRH) +
Gonadotrophin releasing
+
(GnRH)
Thyrotrophin releasing(TRH) +
Growth hormone
releasing(GHRH)

6. PITUITAEY LIKE CYTOCHEMICAL
HORMONES ORIGIN
•Adenocorticotrophic Syncytiotrophoblast
hormone(ACTH)
•Human chorionic +
gonadotrophin (hCG)
•Human chorionic +
thyrotrophin (hCT)
•Human placental +
lactogen (hPL)

7. Protein hormones are similar
but not necessarily identical with
those produced by the pituitary. For
example placental lactogen is
chemicaly similar to both pituitary
growth hormone and prolactin, but
biological activity of placental
lactogen is much inferior than
prolactin or growth hormone
produced by pituitary.

8. Human chorionic gonadotrophin
Human placental lactogen
Pregnancy specific β-1
glycoprotein (PSβ-1G)

9.  hCG is a glycoprotein
 Molecular weight is 36000-40000 daltons
 It consists of a hormone non-specific α(92
amino acids) and a hormone specific β(145
amino acids) subunit
 The α subunit is biochemically similar to LH,
FSH and TSH
 Β subunit is relatively unique to hCG

10.  It act as a stimulus for the secretion
of progesteron by the corpus luteum
of pregnancy
 The rescue and maintenance of
corpus luteum till 6 weeks of
pregnancy
 It stimulate Leyding cells of the
male fetus to produce testosterone
 It has got immuno-suppressive
activity

11. It inhibit the maternal process
of immunorejection of the fetus
as a homograft
Stimulates both adrenal and
placental steroidogenesis
Stimulates maternal thyroid
because of its thyrotrophic
activity

12.  The half life of hCG is about 24 hours
 By radioimmunoassay it can be detected in the
maternal serum or urine as early as 8-9 days
following ovulation
 The doubling time of hCG concentration in plasma is
1.4-2 days
 It reach maximum levels ranging 100IU and 200IU/ml
between 60-70 days of pregnancy
 The concentration falls slowly reaching a low level of
10-20IU/ml between 100-130 days
 There after it remains constant throughout pregnancy
 Slight secondary peak occur at 32 weeks
 Hormone disappears from the circulation within
2weeks following delivery

13. Multiple pregnancy
Hydatidiform mole or
choriocarcinoma
Pregnancy with a21
trisomy fetus

14.  Itis synthesised by the syncytiotrophoblat of
the placenta.
 Chemically and immunologically similar to
pituitary growth hormone and prolactin.
 HPL in maternal serum is first detected
during the 5th week.
 The level rises progressively from 5micro
gms/ml to 25micro gms/ml until about 36
weeks.
 The plasma concentration of HPL is
proportional to placental mass.

15. Antagonizes insulin action
High level of maternal insulin
helps protein synthesis
HPL causes lipolysis and
proteolysis
Promotes transfer of glucose
and amino acids to the fetus.

16.  Produced by the trophoblast cells
 It can be detected in the maternal serum
18—20 days ovulation.
 PS β– 1 G is a potent immunosupressor of
lymphocyte proliferation
 It prevents the rejection of the conceptus

17.  Early pregnancy factor (EPF)is a protein
,produced by the activated platelets and
other maternal tissues.
 It is detected in the circulation 6 to 24 hours
after conception.
 It is an immunosupressant and prevents
rejection of the conceptus.

18.  Inhibin
, activin, insulin like growth factor,
transmitting growth factor β and epidermal
growth factors are produced by the
syncytiotrophoblast cells.
Functios include,
 Immunosupressive
 Paracrine
 Steroidogenic.

19. A (PAPP-A) is secreted by the
syncytiotrophoblast
It act as an immunosupressant in
pregnancy

20. OESTROGEN: The site of
production is in the
syncytiotrophoblast
Chemical nature: Estrogens are
phenolic steroids with 18 carbon
atoms, charecterized by an
atomic ring.
Estriol is produced in large
amounts during pregnancy.

21.  Maternal cholesterol is converted in by
placenta to pregnenolone and later to
progesterone. Placental pregnenolone
toghether with fetal adrenal pregnenolone is
partly converted to pregnenolone sulphate .
pregnenolone sulphate is then coverted by fetal
adrenals to dehydroepiandrosterone sulphate or
DHEA SO4 ,the most important percurser of
placental oestrogens. This biochemical changes
is produced by hydrolysis of the sulphate to
dehydroepiandrosterone and conversion to
androsterone, followed by aromatization of
oestrogen.

22.  DHEA SO4 of fetal adrenal origin is converted
in the fetal liver to 16- alpha hydroxy DHEA
SO4 which is then converted by placenta to
oestriol in two steps.
 Step 1: Sulphatase removes the so4 radical.
 Step 2: Aromatase converts the A ring to the
phenolic stucture characteristics of
oestrogens.
 Thus the production of oestriol involves the
integration of maternal , fetal and placental
pathways.

23. Oestriol is first detectable at
9weeks (0.05ng/ml) and
increases gradually to about
30ng/ml at term.

24.  Normal oestriol value values signify fetal well-
being.
 Oestriol levels reflects placental functioning
ability.
 Low oestriol level indicates , fetal death, fetal
anomalies (adrenal atrophy, anencephaly, down
syndrome), hydatidiform moles, placental
sulphatase or aromatase deficiency.
 High levels are often associated with multiple
pregnancy and Rh-isoimmunization.
 Declining oestriol levels or their failure to rise on
serial examinations are indicative of placental
insuffiency causing IUGR, PIH, maternal renal
disease.

25. Before 6weeks of pregnancy the
corpus luteum secretes 17-hydroxy
progesterone. Following the development of
trophoblast it is synthesised and secreted
form placenta. The placenta can utilise
cholesterole as a precuser derived from the
mother for the production of pregnenolone
and ultimatly progesterone.

26.  The average levels of progesterone at
12week ,28week, and term approximate
25ng/ml, 80ng/ml, 300ng/ml respectively.
 Low progesterone levels are observed in
ectopic pregnancy and abortion.
 High values are observed in , hydatidiform
mole, Rh-isoimmunization.
 After delivery plasma progesterone level
decreases rapidly and is not detectable after
24 hours.

27.  Oestrogen causes hypertrophy and
hyperplasia of the uterine myometrium.
 Progesterone in conjunction with oestrogen
stimulates growth of the uterus
 It causes decidual changes in the
endometrium and inhibits myometrial
contraction.
 Hypertrophy and proliferation of breat ducts
are due to oestrogen
 Both steroids are required for the adaptation
of the maternal organs to the constantly
increasing demands of the growing fetus.

28.  Oestrogen sensitises the myometrium to
oxytocin and prostaglandins. Oestrogen ripen
the cervix.
 Progesterone along with hCG and decidual
cortisol inhibits T-lymphocyte mediated
tissue rejection and protects the conceptus.
 Together they cause inhibition of cyclic
fluctuating activity of gonandotropin-gonadal
axis ther by preserving gonannnnndal
function

29.  Diagnosisof pregnancy
 Follow up cases who had trophoblastic
tumours
 Detection of functions of feto-placental unit

30.  Main source of production is the corpus
luteum of overy,but part of it may be
produced by the placenta and decidua.
 Relaxin relaxes the symphysis and sacroiliac
joints during pregnancy and also helps in
cervical ripening by its biochemical effect.