PHSI3010 Lecture Notes - Lecture 7: Spermatogenesis, Prolactinoma, Fibroblast
15 Mar 2019
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Document Summary
Hyperprolactinaemia (presence of abnormally high levels of prolactin in the blood) Hypothalamo-pituitarygonadal (hpg) axis: testosterone & oestrogen suppress gnrh release, kisspeptin mediates onset of puberty, the establishment of hpg axis & steroid negative feedback loop. *gnrh is central regulator of reproduction (influenced by many factors) Steroidogenesis: lh stimulates steroidogenesis e. g. lh control of testosterone synthesis (in leydig cells) Hypogonadism: deficiency in androgen secretion and/or sperm production (androgen deficient = infertile) Causes: testicular- primary leydig cell dysfunction e. g. klinefelter"s xxy, hypothalamic-pituitary- secondary leydig cell dysfunction e. g. inactivating mutations in kiss1r. Spermatogenesis (activated during puberty: spermatocytogenesis (mitotic proliferation or clonal expansion, meiotic division (genetic reduction & recombination, marked by movement from basal to luminal region of seminiferous tubule. Steroids essential for normal sertoli cell function & spermatogenesis: fsh, androgen. Cellular ageing: ageing associated with gradual decline in performance of organ systems. Increased cell turnover, altered gene expressions and pathologies of ageing: total cell lifespan determined by number of cell divisions (generations)
