Reproductive Physiology Flashcards
MIH ( AMH)
Mullerian-inhibniting hormone (MIH)
also called
anti-Mullerian hormone (AMH)
X → DHT
a rxn catalyzed by 5a-reductase
X is T (testosterone)
DHEA
(de. hydro.epi.andro.sterone)
de. hydro.epi.andro.sterone
- Formed as a product of the 2nd rxn of sex steroid synthesis.
Note: It functions as a metabolic intermediate in the biosynthesis of the androgen and estrogen sex steroids both in the gonads and in various other tissues.
SRY
Sex-determining Region of Y chromosome
List male androgens:
Testosterone (T)
- androstenedione (precursor of extraglandular estrogen in men)
- DHEA
- DHT
genital swelling (- )DHT/f
labia majora
which one of the following can not be detected during 6-7 wks gestation period:
A- germ cells
B- seminiferous tubules
C- leydig cells
D- sertoli cells
C- leydig cells appear later- 8-9 weeks
Choice A might have been difficult to eliminate. Indirectly, it’s been given that during 6-7 weeks sertoli cells enclose germ cells.
Normal levels of testosterone (T), Estrogen (E) and estradiol 17B depends on:
age
gender
health status
time of the day
women: phase of menstrual cycle
Other hormones in the same family as LH/FSH
TSH and hCG
•FSH, LH, TSH, hCG are all are glycoproteins with à and ß subunits
- à chains of TSH, hCG. LH and FSH are the same
- ß chain confers specificity
external genitalia-f
clitoris
labia mjora
labia minora
lower vagina
Morris Syndrome
Androgen insensitivity syndrome
Female differentiation at 9 weeks:
Enumerate the events
- Activation: XX activation (both)
- Mitosis: Germ cells → oogonia
- Meiosis: oogonia
- Support: cells surrounded by granulosa cells and stroma
- Theca cell development from stroma
- Meiosis arrest in late prophase
Androgen insensitivity syndrome
Mode of inheretance
Genotype and phenotype
X-Linked recessive due to the absence of androgen receptors on target tissue.male genotype but appears as female phenotype
Genotype: XY
What happens to Wolffian ducts in the absence of Testosterone?
- Wolffian duct regression
- Mullerian duct development ( into fallopian tubes, uterus cervix and upper 1/3 of vagina).
92AA long GnRH
preprohormone
preprohormone → prohormone → decapeptide-GnRH + GAP
precursors of theca and leydig cells
mesenchymal stromal cells
One of 2 cell types that is indifferent in both m and f; and is present in the 1st 5 week in-utero gonals.
Identify compounds A and B (sex steroid synthesis)
A → 17à-hydroxypregnenolone → B
A- pregnenolone
B- DHEA
♦ 2nd and 3rd reactions of the synthesis of sex steroids, which takes place in SER. They are also common for both m and f.
testes develop from —— via action of SRY region of Y chromosome.
primitive gonads
time period at which the external genitalia of both genders begin to differentiate
~9-10 wks
sex steroid metabolism is similar to ……….
similar to corticosteroids and mineral corticoids metabolism
- metabolized mainly in liver
- excreted in urine
- with halg life of ~30-60 min
Sex Steroid circulation (sex steroids and progestrone)
Sex steroids are bound to SSBG or albumin.
Sex steroids: testostrone and estrogen
Progestrone circulate bound to corticosteroid binding globulin (CBG).
MIH (AMH) is produced by
sertoli cells
genital tubercle (-) DHT/f
clitoris
the common tissue of labia majora and scrotum
genital swelling
Total # of Cs for male sex steroids:
19
Specific events of male gonadal differentiation:
- 6-7 weeks
- 8-9 weeks
In males at 6-7 wks
- Semineferous tubules form
- sertoli cells enclose germ cells
8-9 wks
- Leydig cells appear
The time periods at which testes are distinguishable and functional
- Distinguishable in 7 weeks
- Fully functional in 14-15 wks( additional 7-9 weeks).
Testosterone paracrine action on Wolffian ducts
Development of:epididymis, vas deferens, seminal vesicles and ejaculatory ducts.
During female gonadal differentiation (~9wks) some of these cells undergo meiosis:
oogonia
The source function of testostrone during development of male internal genitalia
Testosterone (produced by leydig cells) act in paracrine manner to stimulate development of wolffian ducts into epididymis, vas deferens, seminal vesicles and ejaculatory duct.
The common tissue of clitoris and glans penis:
genital tubercle
Regardless of the genetic make up, prior to 6 weeks gestation, the fetus has indifferent gonads that have formed from —–
the genital ridges
Note: at 6 wks gestation, migratory germ cells invade the genital ridges.
From —- cell, theca cells develop.
Hint- 9wks, female gonadal differentiation
stroma
GnRH binds the plasma membrane of ——- in pituitary and stimulates the release of both FSH and LH.
gonadotroph
5-alpha-reductase converts testosterone to this compound
DHT
The common target tissues of DHT in both m/f:
Genital tubercle
Genital swelling
Urethral fold
Urogenital sinus
Precursor of extraglandular estrogens in men
Andro.sten.edione (made from DHEA)
Note 1 : both ovaries and testies produce estrogen and androgen. Androgens produced from adrenal cortex in both sexes gets convrted to estrogen in adipose and other extragonadal external adrenal tissues.
Note 2: Androstenediol, or 5-androstenediol (abbreviated as A5 or Δ5-diol), also known as androst-5-ene-3β,17β-diol
The time frame whithin which the androgenic hormones take effect in women
After menopause androgenic hormones are produced by adrenals
The period by which the leydig cells appear during m. gonadal differentiation
By 8-9 week
A period of gonadal differentiation, in which (both m/f) in-utero gonals are indifferentiated
1st 5 week- indifferent gonals
genital tubercle (+) DHT (m)
glans penis
T is produced by
leydig cells of testes
precursor of sertoli cells (cell type found in the first 5 week)
coelomic epithelial