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# Function of Testicular Hormones * Spermatogenesis * Secondary sexual characters * Male sexual characters which requires DHT as enlargement of prostate and external genitalia * Male sexual behavior * Anabolic effect * AMH is important in sex differentiation # Transport of Testosterone Testostero...

# Function of Testicular Hormones * Spermatogenesis * Secondary sexual characters * Male sexual characters which requires DHT as enlargement of prostate and external genitalia * Male sexual behavior * Anabolic effect * AMH is important in sex differentiation # Transport of Testosterone Testosterone in male synthesized in the testes and secreted immediately into blood circulation (no storage) while in female it produced by the ovary in little amount. In the blood circulation testosterone present as follow: * **Unbound (free) testosterone** represents the biologically active fraction constitutes about 2% of the total plasma testosterone in male and 1% in female. * **Bound testosterone** represents the biologically inactive and reservoir fraction; the proteins that bind to testosterone are of two forms which are: * Albumin...40% of the total plasma testosterone is bound to albumin in male and 20% in female. * Sex hormone-binding globulin (SHBG) or called testosterone-estrogen binding globulin (TEBG)... 58% of the total plasma testosterone is bound to SHBG in male and 79% in female # Metabolism of Testosterone Two pathways that are metabolize testosterone: * In liver, testosterone oxidized to 17-ketosteroid which is followed by conjugation at position 3 by glucuronate or sulphate forming 17-ketosteroid 3-glucuronate or sulphate which is more water soluble, so it excreted through the bile duct where majority is reabsorbed by enterohepatic circulation so its final excretion mainly by urine and to less extent by feces and rarely through the skin. * Peripheral conversion of testosterone into the potent metabolite (DHT) and to less extent into estradiol (E2) which thereafter estradiol is metabolized through estrogen metabolic pathway.