PHSI3010 Lecture Notes - Lecture 3: Sex Steroid, Low-Density Lipoprotein, Estrogen

• School: University of Sydney
• Department: Physiology
• Course: PHSI3010
• Professor: any

Document Summary

Lecture 3: reproductive messengers 2 sex steroids. Steroids are made from cholesterol: ldl uptake, de novo cholesterol synthesis, cholesterol storage. Gonadal steroidogenesis is affected by gonadotrophin signalling: acute & chronic effects: principle steroids synthesised & secreted are determined by cellular enzyme profiles, circulating levels of principal sex steroids are reflected by cellular enzyme profiles & activity. Sex steroid binding proteins are key regulators of free" active hormone fraction. Abnormalities in sex steroid binding proteins are associated with a no. of pathologies. Rules of thumb: increased shbg = increase in ratio of e2:t & vice versa. De-activation" and clearance (extraction/excretion) act to regulate free" active hormone fraction: urinary steroid levels are ~10% of circulating levels. Sex steroids act through genomic & rapid" cognate receptor mechanisms. Key determinants of sites of steroid receptor action: relative levels of free and active sex steroid, relative levels of active sex steroid receptor.