Testosterone is the main androgen in men and is synthesized primarily in the Leydig cells of the testes under stimulation from LH. Androgens bind to nuclear receptors in target cells and promote male secondary sex characteristics, reproductive organ maturation, protein synthesis, and muscle growth. Testosterone levels in males are typically 300-1000 ng/dL while in females they are 15-75 ng/dL.

2. Androgen actually means male sex hormones.
Testosterone is the main androgen in men. It is
mainly synthesized from Leydig cells or
interstitial cells of the testes under the
influence of ICSH (Interstitial Cell Stimulating
Hormone) of anterior pituitary.

3. • Large Amount:
 Leydig cells (Testes)
• Small Amount:
 Thecal cells (Ovaries)
 Adrenal glands

4. Androgens bind to specific nuclear receptor in a target cell.
Androgen Cytoplasmic androgen receptor (AR)
Testosterone receptor complex + DNA
Androgen response element of target gene
DNA transcription
Protein synthesis

5. • Development of male secondary sexual characteristics
• Maturation of reproductive organs
• Promotes protein synthesis
• Increase muscle mass

6. 
1. Acne
2.Hirsutism
3.Menstrual irregularities

1. Impotence
2. Decreased spermatogenesis

1. Abnormal sexual maturation
2. Growth disturbance

7. Testosterone
5α- Dihydrotestosterone (DHT)
Androstenedione
Dehydroepiandrosterone

8. Methyltestosterone
Fluoxymesterone
Nandrolone decanoate (i.m.)
Oxandrolone (p.o.)
Stanozolol (p.o.)
Ethylestrenol (p.o.)

9. Oestrogen
Ketoconazole
Spironolactone

10. Flutamide
Bicalutamide
Cyproterone
Spironolactone
Finasteride
Dutasteride

11. 1. Oestrogens decrease androgen levels by inhibiting
gonadotropin secretion.
2. Ketoconazole (antifungal) inhibits adrenal and gonadal steroid
synthesis.
3. Spironolactone, an aldosterone antagonist, inhibits testosterone
synthesis, also competitively blocks androgen receptors.
4. Androgen receptor antagonists block action of androgens on
the target cell.
5. Finasteride and Dutasteride block the enzyme 5α- reductase
needed to convert to dihydrotestosterone (DHT) from
testosterone.

12.  Testosterone Levels:
 Male: 300- 1000 ng/dL
 Female: 15- 75 ng/dL
 Dihydrotestosterone:
In most target cells, 4-5 double bond is reduced, converts
testosterone [ abundant in muscle and liver] to dihydrotestosterone
(DHT) [e.g. prostrate, seminal vesicles, skin etc].