* Urinary Metabolites of testosterone and adrenal androgens: 17 ketosteroids (androsterone and étiocholanone)

* Leydig cells differentiate from the 7th week and testosterone secretion appears to 9th SA; peaks between 14 and 18 SA (adult rate)

* At birth, the plasma level of testosterone is low but increases in the neonatal period, reaching a peak around the second month of life; it fell from the 6th month he drops and stays low until puberty

* Androgens promotes the storage of muscle glycogen, sodium retention and maintenance of calcium in the skeleton; it stimulates erythropoiesis.

* Immature Sertoli cells of the fetal testis produce from the 7th SA Anti-Mullerian hormone that is responsible for the regression of Müller channel (which gives the female genitals)

* Anti-Mullerian hormone deficiency is responsible for co-existence in a subject whose genitals are masculine, male and female internal organs (but not the ovaries).

* The androgen binding protein (ABP): very close to the TeBG; largely secreted into the lumen of the seminiferous tubules. She maintains a concentration of Andrena 10 x higher than that of plasma.

* The Sertoli cell secretes estradiol by testicular flavoring

* Prolactin tends to depress the secretion of GnRH. .beta.-Endorphin has the same action

* Ketoconazole can inhibit high doses and prolonged synthesis of testosterone

* The dystrophy -> late hypogonadism (normal pubertal development, secondary infertility).

* Eunuchoidism: + impuberism excessive size due to the lengthening of the lower limbs (macroskelia); increase in scope; increasing the diameter bitrochantérien compared to bi-aromial diameter; insufficiency of thoracic perimeter.

* Infantilism: combines hypogonadism and GH deficiency; infantile aspect, harmonious

Klinefelter Syndrome
Klinefelter Syndrome

Klinefelter syndrome:

* Defined by a chromosomal abnormality characterized by the presence of at least two X chromosome in a subject of male phenotype, whose gonads are testes which explains the presence of a Y chromosome or chromosome fragment.

The typical clinical form corresponds to the karyotype 47, XXY (80 to 90% of cases)

* After puberty, the clinical picture is evocative and associates:

* The small size of the testicles is constant

* The external genitalia and prostate are generally well developed

Gynecomastia * (40%)

* Aspect eunuchoid with macroskelia (lower limbs increased)

* Muscles undeveloped + gynoid fat distribution

* The pubic hair is normal in 3 quarts of cases; moderate facial and body hair; 40% are beardless

* The intellectual level is generally poor; mental retardation with IQ <80 and behavioral disorders

* Frequent associated events: malformations (especially skeletal); neurological disorders (seizure disorders);thrombophlebitis; cancers (seminoma and Leydigome) and blood diseases; autoimmune diseases (lupus);osteoporosis; diabetes; … thyroid dysfunction.

* FSH is increased (hypogonadism of testicular origin); the LH aumentation is lower and variable.

* The testosterone is in the low values ​​of normal. It rises in ß-hCG but not enough.

* Report DHT / testosterone always decreased;

* Plasma estradiol is normal or high

* The mosaics (46 XX / 47XXY) give more attenuated tables

* The presence of Barr more than 5% of cells signs the existence of two X chromosomes


* Competitive inhibitors of the active transport of iodine in the thyroid: bromine; lithium; … thiocyanate.

* In case of iodine deficiency is the privileged way of orientation to the T3

* Thyroid hormones have a very long half life: 7 days for T4 and T3 for 36 h.