Lecture written and presented by Paul J. Turek MD FACS, FRSM. Dr. Turek is the Director of the The Turek Clinic in San Francisco and Former Professor and Endowed Chair at the University of California San Francisco (UCSF).
Embryology-TestisGonocytes Testosterone• Inactive until puberty • 1st surge in utero• Meiosis inhibited by MIS • 2nd surge in neonatal period• Pubertal testosterone meiosis • 3rd rise at puberty; peaks in 2nd to 3rd decade Testosterone (ng/dL) 600 400 200 100 0 Adult Senescence
Embryology-Mesonephric Duct AbnormalitiesCongenital Absence of the Vas Deferens (CAVD) • Unilateral: most azoospermic • Bilateral: all azoospermic • Any segment of Wolffian duct • If ipsilateral kidney also absent: No CFTR mutations • If ipsilateral kidney is present: 80% have CFTR mutations CF results in: Pneumonia, pancreatic insufficiency, bowel obstruction, sinusitis, nasal polyps, and death by 35 years of age.
Embryology-QuestionsWhen does meiosis begin in the human male? PubertyWhat hormone is responsible for regression of MIS female internal genitalia?What gene is responsible for male sexual SRY, (SOX-9) differentiation?What gene mutation should be examined CFTR=cystic in men with idiopathic ejaculatory fibrosis trans- duct obstruction? membrane regulatory geneHow many testosterone peaks have occurred by 3-First trimester, the time a man reaches age 30? neonatal and adult
(caput) 10 days4 x 3 cm Rete testis (20mL) (corpus) 80 64 days %ge rm 600 10-15 cells (cauda) millionlobules sperm Need 3 months to make and ejaculate sperm. Soft, small testes imply a sperm production problem
H-P-G Axis: Testosterone• Testosterone comes in several forms.• Only free and albumin (weakly bound) are “active.”• SHBG-bound is inactive. Free/unboundAlbumin bound 1-2% SHBG bound 60% 40% SHBG-T Total Free T Testosterone Bioavailable Testosterone Albumin-T