Synthesis of androgens

Synthesis of androgen, biochemical and physiological pathways

1. Nature and synthesis of androgen Prepared by: Anish Dhakal (Aryan) MBBS Student Patan Academy of Health Sciences

2. Androgen is a steroid hormone. Types : 1. Testosterone 2. Dihydrotestosterone 3. Androstenedione 5-12 mg of testosterone produced daily by testes converted to more active form dihydrotestosterone in extra glandular tissues. 19 carbon compounds

3. Testosterone A prohormone ! Dihydrotestosterone ( DHT ) more potent than testosterone.

4. ANDROGENS Sites of synthesis in males -- primarily testes- leydig cells; also in adrenals (zona reticularis and fasciculata ) Androgens in Females   Sites of synthesis-ovaries; tiny amount by theca cells of ovarian follicles , adrenals , placenta   Physiological significance Apparently not necessary for normal menstrual cycling, but may be involved in pubertal growth spurt, libido . Precursor of hormone is cholesterol.

5. Testosterone: Leydig cells Cholesterol can either be synthesized de novo in the Leydig cell can also be LDL derived Migrate to inner mitochondria by stAR ( steroidogenic Acute Regulatory) protein first converted to Pregnenolone by Cyt P450 side chain cleavage enzyme ( P450SCC ) which then forms androstenedione by two pathways: Through progesterone (Progesterone ( or ∆4 ) pathway) Through 17- hydroxypregnenolone . ( Dehydroepiandrosterone or ∆5 pathway)

6. Testesterone Transport largely bound to albumin and to a specific transport protein, Testosterone estrogen binding protein ( TEBG ) or sex hormone-binding globulin ( SHBG ) Currently, protein bound testosterone is also regarded as biologically active Liver mainly metabolizes androgens to 17- ketosteroids,which are excreted in urine