Download Disorders of sex hormones (Carolina Gomes)

DISORDERS OF SEX
HORMONES IN ONTOGENESIS
Carolina Gomes, group 1
Sex determination- ontogenesis
• Depends on the SRY- determines if gonads develop into ovaries or
testis
• Sertoli cells produce anti-Mullerian hormone so the development of
Mullerian duct into female genitalia is supressed. Development of
Wolffian duct into male genitalia
• In ovaries, no Mullerian hormone and no testosterone  female
genital tract
Genetic X phenotype
Failed gonadal development
• Gonadal dysgenesis:
• Congenital development disorder
• Loss of germ cells on developing gonads of an embryo
• No influence of hormones
• Female genitalia
• Agonadia:
• 46 XY individuals
• gonads can’t be detected, abnormal external genitalia and rudimentary
Mullerian or Wolffian derivatives
• Fetal testes functioned sufficiently long to inhibit Mullerian development
• Anorchia:
• XY disorder, testes absent in birth
• Few weeks of fertilization  embryo develops rudimentary testes
• If testes fail to develop within 8w  baby develop female genitalia
• Low testosterone, high FSH and LH, low anti-Mullerian hormone
Chromossomal abnormalities
• Turner syndrome: 45X
• CT strands are formed in
place of normal ovaries
and external features are
more likely to be female.
• Klinefelter’s syndrome:47XXY
• Testes are formed in a way
that spermatogenesis is
possible but androgen is
impaired. Androgen deficiency
leads to an inadequately male
appearance.
• Trisomy X 45XXX
• Woman
• Mild effects, microcephaly,
tall stature, epicanthal folds,
normal fertility
• Hermaphroditism
• both testes and ovaries
are simultaneously formed
• Translocation of some parts
of Y chromosome, including,
SRY gene, onto a X can
lead to formation of bisexual
gonads and intersexual
characteristics
• Male pseudohermaphroditism
• Intersexual or female sexual
characteristics are present
• Causes:
• A) gonadotropin deficiency,
when gonadotropin release is
suppressed due to an increase
formation of female sexual
hormones by a tumor
• B) defects in gonadotropin
receptors
• C) enzyme defects of testosterone
synthesis
• Female pseudohermaphroditism
• Causes:
• A) iatrogenic administration
• B) increased formation of androgens,
in an androgen producing tumor
• C) enzymatic defect in adrenocortical
hormone synthesis
Control of GnRH, FSH and LH in males
Control of FSH and LH in female during
menstrual cycle
Hormonal dysfunction
• GnRH in childhood, adolescence and adults
• Pulsatile secretion of GnRH
• At pituitary, GnRH stimulates the synthesis and secretion of gonadotropins, FSH
and LH
• These processes are controlled by GnRH pulses and by feedback from androgens
and estrogens
• Decrease GnRH pulses  FSH
• Increase GnRH pulses  LH
• Males GnRH is secreted in pulses at a constant frequency
• In Females, the frequency of pulses varies during menstrual cycle and there is an
increase in GnRH just before ovulation
Androgen
Male
Precociuous
puberty
• By tumor or
injury of
brain that
makes sex
hormones
to occur
early
Female
Precocious
pseudopuberty
• Induced by sex
steroids from
adrenal
insufficiency
Congenital adrenal
Hyperplasia
• due to poor cortisol
 ACTH 
hyperplasia of cells
• Deficiency in one
hormone leads to
increase in another
Androgen
Male
Hypogonadotropic hypogonadism
Primary: problem at gonads but not in
hypothalamus and pituitary
Secondary: acquired, due to head
trauma, drugs
Estrogen and progesterone
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References
• SILBERNAGL, Stephan, LANG, Florian, Color Atlas of
Pathophysiology, Thieme, 2nd eddition, New York
• Arthur C. Guyton & John E. Hall (2011). Mississippi: Textbook of
Medical Physiology, (12th Ed.)
• DAMJANOV, Ivan, Pathophysiology, Saunders, 2009, Philadelphia