Androstenedione

What is androstenedione?

Androstenedione is a steroid hormone and belongs to the group of androgens (male sex hormones) but is present and has important functions in both women and men. The hormone is produced mainly in the adrenal glands (adrenal cortex) and in the gonads, the ovaries in women and the testicles in men. Androstenedione functions mainly as a precursor to other sex hormones, especially testosterone and estrogens (estradiol). It can therefore be seen as a central building block in the body's hormonal balance between androgens and estrogens.

How is androstenedione controlled?

The production of androstenedione is regulated via several hormonal axes:

• ACTH (adrenocorticotropic hormone) from the pituitary gland, which stimulates the adrenal glands
• Luteinizing hormone which affects the ovaries and testicles
• Age, gender and hormonal life stage (puberty, childbearing age, menopause)

Since both the adrenal glands and the gonads contribute to production, changes in several different systems can affect androstenedione levels.

What does androstenedione do in the body?

Androstenedione itself has a relatively weak androgenic effect, but its main importance lies in the fact that it:

• is converted to testosterone via the enzyme 17β-HSD
• is converted to estrogens (mainly estrone and estradiol) via aromatase
• indirectly contributes to the development and maintenance of secondary sex characteristics

In women, androstenedione is an important source of both androgens and estrogens, especially after menopause when ovarian estrogen production decreases. In men, the contribution is smaller in relation to testicular testosterone production, but may still be clinically relevant.

Why measure S-Androstenedione?

S-Androstenedione is primarily analyzed when hormonal imbalance is suspected, especially when assessing androgen production and its origin. The test is often used as a complement to testosterone , DHEA-S and SHBG.

The analysis is particularly relevant in the following cases:

• Suspected hyperandrogenism in women
• Investigation of PCOS (polycystic ovary syndrome)
• Unclear menstrual disorders or infertility
• Suspected adrenal gland involvement or hormone-producing tumor

Common indications for androstenedione testing

• Increased hair growth (hirsutism), acne or androgenic alopecia in women
• Irregular or absent menstruation
• Infertility or absence of ovulation
• Suspected PCOS or other androgen disorder
• Investigation of early puberty or virilization

What can an elevated androstenedione cause?

Elevated levels of androstenedione usually indicate increased androgen production from the adrenal glands and/or ovaries.

Common causes include:

• PCOS – one of the most common causes in women
• Adrenal hyperplasia (incl. mild forms, e.g. non-classical CAH)
• Hormonal-producing tumors in the adrenal gland or ovary (uncommon but important to rule out)
• Stress-related ACTH increase (may contribute in some cases)

Symptoms that can be seen with high androstenedione

• Acne and oily skin
• Increased hair growth on the face or body
• Male pattern hair loss
• Irregular or absent menstruation
• Impaired fertility

In men, isolated high androstenedione rarely causes clear symptoms, but can occur with adrenal gland involvement.

What can low androstenedione mean?

Low levels of androstenedione are less often seen as a primary problem, but can occur with reduced hormone production. Below are some possible causes:

• Adrenal insufficiency (primary or secondary)
• Pituitary insufficiency (low ACTH/LH)
• Old age or postmenopausal phase
• Some drugs that inhibit steroid production

Symptoms of low androstenedione

• Low energy and decreased vitality.
• Decreased libido.
• Signs of generally low sex hormone levels.

Low androstenedione is often interpreted in relation to other hormones rather than as an isolated finding.

Sample collection and important preparations

• Samples are usually taken in the morning
• In menstruating women, the day of the cycle is important (often days 2–5)
• Hormonal contraceptives can affect the result
• Androstenedione is always interpreted together with other hormones

Medications and other sources of error

Several factors can affect androstenedione levels and interpretation:

• Hormonal contraceptives
• Glucocorticoids
• Anabolic steroids or androgen therapy
• Stress and acute illness

It is therefore important to always interpret the value in relation to clinical picture, other hormone analyses and the conditions of sampling.

Reference range for androstenedione

Reference range for S-Androstenedione is given in the unit nmol/L and differs depending on gender and age. When interpreting, it is important to always base the results on the reference range used by the analyzing laboratory.

For adults, the following reference ranges are used:

• Women 18–49 years: 1.0–7.2 nmol/L
• Women ≥ 50 years: 0.5–3.0 nmol/L
• Men ≥ 18 years: 1.2–5.0 nmol/L

In women of childbearing age, androstenedione levels can also vary with the menstrual cycle, which means that the time of sampling can be important for interpretation. The result should therefore always be assessed together with the clinical picture and other hormone tests, such as testosterone, DHEA-S, SHBG, LH and FSH.