{"id":4422426,"date":"2025-01-11T18:21:54","date_gmt":"2025-01-12T00:21:54","guid":{"rendered":"https:\/\/myendoconsult.com\/learn\/topics\/reproductive-physiology\/"},"modified":"2025-01-11T18:23:33","modified_gmt":"2025-01-12T00:23:33","slug":"reproductive-physiology","status":"publish","type":"oen_topic","link":"https:\/\/myendoconsult.com\/learn\/topics\/reproductive-physiology\/","title":{"rendered":"Reproductive Physiology"},"content":{"rendered":"\n<h2 class=\"wp-block-heading\">TESTOSTERONE AND ESTROGEN SYNTHESIS<\/h2>\n\n\n\n<h3 class=\"wp-block-heading\">Overview of Steroid Synthesis<\/h3>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Three coelomic-derived glands<\/strong>\u2014adrenal cortex, ovary, and testis\u2014produce steroids in response to <strong>anterior pituitary hormones<\/strong>:\n<ul class=\"wp-block-list\">\n<li><strong>Corticotropin (ACTH)<\/strong>: Stimulates <a href=\"https:\/\/myendoconsult.com\/learn\/the-formation-and-structure-of-the-adrenal-cortex\/\"  data-wpil-monitor-id=\"199\">adrenal cortex<\/a>.<\/li>\n\n\n\n<li><strong>Gonadotropins (LH\/FSH)<\/strong>: Stimulate gonads (testes\/ovaries).<\/li>\n<\/ul>\n<\/li>\n\n\n\n<li><strong>First Critical Step<\/strong>: Cleaving <strong>cholesterol<\/strong> into <strong>pregnenolone<\/strong> (C21 steroid precursor) + <strong>isocaproaldehyde<\/strong>.\n<ul class=\"wp-block-list\">\n<li>Occurs in <strong>adrenal cortex, testicular Leydig cells, ovarian theca cells, trophoblast cells (placenta),<\/strong> and certain brain cells.<\/li>\n<\/ul>\n<\/li>\n\n\n\n<li><strong>Resulting Steroid Families<\/strong>:\n<ul class=\"wp-block-list\">\n<li><strong>Androgens<\/strong>: C19 steroids.<\/li>\n\n\n\n<li><strong>Estrogens<\/strong>: C18 steroids.<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n\n\n\n<h3 class=\"wp-block-heading\">Pathway to Androgens<\/h3>\n\n\n\n<ol class=\"wp-block-list\">\n<li><strong>Pregnenolone<\/strong> \u2192 17\u03b1-hydroxypregnenolone (<strong>17\u03b1-hydroxylase\/P450c17<\/strong>).<\/li>\n\n\n\n<li><strong>17,20-lyase activity<\/strong> of P450c17 \u2192 produces C19 androgens (dehydroepiandrosterone [DHEA], androstenedione).\n<ul class=\"wp-block-list\">\n<li>Most adrenal androstenedione depends on <strong>DHEA \u2192 androstenedione<\/strong> via <strong>3\u03b2-HSD<\/strong>.<\/li>\n<\/ul>\n<\/li>\n\n\n\n<li><strong>Androstenedione<\/strong> \u2192 <strong>testosterone<\/strong> via <strong>17\u03b2-ketosteroid reductase (17\u03b2-HSD3)<\/strong> in adrenal or gonads.<\/li>\n<\/ol>\n\n\n\n<h3 class=\"wp-block-heading\">Androgen Production by Gonads<\/h3>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Testis<\/strong> (Leydig cells): 95% of <a href=\"https:\/\/myendoconsult.com\/learn\/clomid-or-testosterone-injections-in-male-hypogonadism\/\"  data-wpil-monitor-id=\"198\">male <strong>testosterone<\/strong><\/a> (~7 mg\/day) secreted under <strong>LH<\/strong> control.\n<ul class=\"wp-block-list\">\n<li>Local effect amplified by <strong>5\u03b1-reductase type 2<\/strong> \u2192 <strong>dihydrotestosterone (DHT)<\/strong> (hair follicles, prostate).<\/li>\n\n\n\n<li>In blood, testosterone is <strong>bound<\/strong> to sex hormone\u2013binding globulin (SHBG).<\/li>\n\n\n\n<li>Liver conjugation \u2192 excreted by kidney (water-soluble).<\/li>\n<\/ul>\n<\/li>\n\n\n\n<li><strong>Adrenal DHEA<\/strong>:\n<ul class=\"wp-block-list\">\n<li>Weak androgen \u2192 major component of urinary <strong>17-ketosteroids<\/strong>.<\/li>\n\n\n\n<li>~60% of 17-ketosteroids come from adrenal DHEA; normal excretion higher in men (testicular plus adrenal contribution).<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n\n\n\n<h3 class=\"wp-block-heading\">Ovarian Androgen and Estrogen Zones<\/h3>\n\n\n\n<ol class=\"wp-block-list\">\n<li><strong>Granulosa cells<\/strong>: Main <strong>estrogen<\/strong> (e.g., estradiol) formation.<\/li>\n\n\n\n<li><strong>Theca cells<\/strong>: More <strong>androgen<\/strong> production tendency.<\/li>\n\n\n\n<li><strong>Hilar cells<\/strong>: Predominantly <strong>androgen<\/strong> formation.\n<ul class=\"wp-block-list\">\n<li>Balance of these cells ensures <strong>normal femininity<\/strong>; imbalance \u2192 <strong>androgenicity<\/strong>.<\/li>\n\n\n\n<li><strong>Corpus luteum<\/strong>: Major source of <strong>progesterone<\/strong> in the ovary.<\/li>\n<\/ul>\n<\/li>\n<\/ol>\n\n\n\n<h3 class=\"wp-block-heading\">Conversion to Estrogens<\/h3>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Testosterone<\/strong> \u2192 <strong>estradiol<\/strong>, or <strong>androstenedione<\/strong> \u2192 <strong>estrone<\/strong>, by <strong>aromatization<\/strong> of the steroid A ring.\n<ul class=\"wp-block-list\">\n<li><strong>Estradiol<\/strong> more potent than <strong>estrone<\/strong>; <strong>estriol<\/strong> is a weak excretory product.<\/li>\n<\/ul>\n<\/li>\n\n\n\n<li><strong>Estrogen Transport<\/strong>: Bound to <strong>SHBG<\/strong> and albumin in blood.<\/li>\n\n\n\n<li><strong>Estrogen Inactivation<\/strong>:\n<ul class=\"wp-block-list\">\n<li>Primarily in <strong>liver<\/strong> \u2192 estradiol to estrone to estriol, oxidation to inert compounds, or <strong>glucuronic acid<\/strong> conjugation.<\/li>\n\n\n\n<li><strong>Enterohepatic circulation<\/strong>: Excretion into bile \u2192 partial reabsorption.<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n","protected":false},"excerpt":{"rendered":"<p>TESTOSTERONE AND ESTROGEN SYNTHESIS Overview of Steroid Synthesis Pathway to Androgens Androgen Production by Gonads Ovarian Androgen and Estrogen Zones Conversion to Estrogens<\/p>\n","protected":false},"featured_media":0,"template":"","oen_topic_chapter":[685],"class_list":["post-4422426","oen_topic","type-oen_topic","status-publish","hentry","oen_topic_chapter-reproductive-disorders","post-wrapper","thrv_wrapper"],"_links":{"self":[{"href":"https:\/\/myendoconsult.com\/learn\/wp-json\/wp\/v2\/oen_topic\/4422426","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/myendoconsult.com\/learn\/wp-json\/wp\/v2\/oen_topic"}],"about":[{"href":"https:\/\/myendoconsult.com\/learn\/wp-json\/wp\/v2\/types\/oen_topic"}],"version-history":[{"count":3,"href":"https:\/\/myendoconsult.com\/learn\/wp-json\/wp\/v2\/oen_topic\/4422426\/revisions"}],"predecessor-version":[{"id":4422429,"href":"https:\/\/myendoconsult.com\/learn\/wp-json\/wp\/v2\/oen_topic\/4422426\/revisions\/4422429"}],"wp:attachment":[{"href":"https:\/\/myendoconsult.com\/learn\/wp-json\/wp\/v2\/media?parent=4422426"}],"wp:term":[{"taxonomy":"oen_topic_chapter","embeddable":true,"href":"https:\/\/myendoconsult.com\/learn\/wp-json\/wp\/v2\/oen_topic_chapter?post=4422426"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}