Source & Biosynthesis
- Mainly by Leydig cells of testis (95% by leydig cells, 5% by adrenals)
- In females, both ovaries and adrenals convert estradiol.
- Same biosynthesis pathway as estrogen.
- Testosterone cypionate
- Testosterone enanthate
- Nandrolone decanoate
Mechanism of action
Steroidal receptors, androgenic receptors intracellularly present, binding leads to changes in pattern of synthesis of estrogen.
Routes of administration –oral, sublingual, transderma, topical
Protein binding – bind sex hormone binding globulin SHBG
5α-reductase – converts testosterone into dihydrotestosterone
Conjugation occurs and excreted in form of urates
Physiological & Pharmacological Effects
Development of primary sex characteristics
Development in utero and whole life.
Development of secondary sex characteristics
Like changes in growth of hair patterns, change in skin thickness, which becomes oilier, deepness of voice due to growth of larynx and vocal cords, muscular, skeletal growth.
Effect on growth & Ca+2 metabolism
Increased deposition, thickness of bones is increased
Epiphyseal closure is accelerated
Increase in muscular mass esp. shoulder girdle.
Androgens increase synthesis of hepatic proteins, clotting factors, triglyceride lipase, alpha 1 antitrypsin and other proteins.
Effect on water & electrolytes
Increased resorption of sodium from distal convulated tubules leading to edema in susceptible patients.
Effect on blood
Increased secretion of erythrocytes, increased RBCs
Increased activity, increased protein anabolism decreased catabolism
Increased Na, K, Ca, N
Increased tolerance in athletes.
- Replacement therapy in male
- Primary hypogonadism
- Gynaecological disorders in female
- Male contraception
- Catabolic & wasting states –anabolic effects
- Anemia –refractory cases, now replaced by recombinant erythropoietin
- Growth stimulators
In those young boys having delayed puberty and growth but used with caution. Also cause closure of epiphysis and can retard growth.
Used to slow down aging process.
- Anabolic steroids in sports
Not therapeutic use but misuse, to increase performance because of anabolic effects.
- Affects CNS
- Sexual functions
a. Increased bilirubin
d. Increased incidence of adenoma and carcinoma of liver
e. Some reports of hepatic failure with use
- Prostate hyperplasia –benign prostatic hyperplasia, urinary retention especially in older patients
- Also increase incidence of prostatic cancer
- Suppress sperm production -azospermia
- Psychotic behavior
- Psychological dependence
- Na retention
Contraindications & Cautions
- Pregnant females causing masculinization of female fetus or under masculinization of male fetus.
- Hepatic / CVS / Renal / Cancer patients (prostatic, breast)
- Anti androgens are the inhibitors of testosterone secretion
- They are released in non pulsatile nature,
- GnRH analogs – Goserelin / Nafarelin are used in Prostate Cancer
- Steroid synthesis inhibitors – Ketoconazole antifungal, inhibits many enzymes of steroid synthesis
- 5α-reductase inhibitors – Finasteride inhibits conversion of testosterone into dihydrotestosterone.
Uses BPH / Male pattern baldness / Hirsutism
Androgen receptor inhibitors
- Flutamide / Bicalutamide
- Spironolactone –inhibition of androgen and aldosterone receptor
Uses Hirsutism / androgenic activity / Prostate Ca
- Drug having Progestational / Androgenic / Glucocorticoid activity
- Weak glucocorticoid activity, Suppression of ovarian functions
- Major active metabolite Ethisterone
- Fibrocystic disease of breast
- Hematological & allergic disorders
- Idiopathic thrombocytopenia purpura
- Angioneurotic edema
- Weight gain
- hot flushes
- breast size
- voice deepening