This androgen, which circulates in the blood in free form – not protein-bound – is two-thirds of ovarian origin, and one third of adrenal origin. This is the “ovarian androgen.”
• Diagnosis of ambiguous genitalia at birth.
• Differential diagnosis of hirsutism.
Sample:
Take preferably in the laboratory and freeze immediately, or centrifuge the plasma and transported to the laboratory in ice.
Typical values:
(This).
In women <3 mg / L (10 nmol / L)
• Part 1 of the cycle:
1.2 to 2.2 mg / L
• 2nd part of the cycle:
1.2 to 4.3 mg / L
• after menopause:
<1 mg / L (3 nmol / L)
Conversion Factors
ug × 5 = 95 nmol
nmol × 0.286 = micrograms
Interpretation:
Coupled to that of testosterone, androstenedione dosage contributes to diagnosis of hirsutism.
Polycystic Ovary Syndrome:
The polycystic ovary syndrome is marked by a spaniomenorrhea or secondary amenorrhea, a tendency to obesity and hirsutism.
The hyperandrogenism results in a rise in the plasma concentration of Δ4-androstenedione> 3 mg / L (3 ng / ml), testosterone is between 0.8 and 1.2 ng / mL.
The plasma concentration of LH, permanently high, increases explosively after injection of GnRH (LH> 60 IU / L), while FSH remains normal or low.
On ultrasound vaginal, both ovaries are large devices with multiple cysts. (See Testosterone and FSH, LH)
Other hirsutism:
• If hirsutism by 21-hydroxylase deficiency or 11-hydroxylase, and later revealed incomplete, increasing androstenedione is associated with increased 17 hydroxyprogesterone
> 5 ng / mL, especially after injection synacthen (See 17 hydroxy progesterone).
• A hirsutism with significant virilization signs recently appeared and rapidly developing evokes a virilizing tumor of the ovary or adrenal. The Δ4-androstenedione and testosterone are very high.
• The Δ4-androstenedione is normal in idiopathic hirsutism.
Adrenal insufficiencies:
The Δ4-androstenedione is greatly diminished in primary adrenal insufficiencies (Addison’s disease).