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Biochemistry I, Barry University March 31, 2005 Steroid Chemistry & Endocrinology Kenneth L. Campbell Professor of Biology University of Massachusetts at Boston.
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Biochemistry I, Barry University March 31, 2005 Steroid Chemistry & Endocrinology Kenneth L. Campbell Professor of Biology University of Massachusetts at Boston
This presentation is made possible by a grant entitled“Shortcourses in Endocrinology at Minority Undergraduate Institutions”from the National Institute of General Medical Sciences (NIGMS) to The Minority Affairs Committee of the Endocrine Society
Steroid Functions • Glucocorticoids & sex steroids support growth & development, especially in the embryo, gonads, brain, & pubertal animal • Glucocorticoids helps maintain glucose homeostasis & modulate stress responses • Mineralocorticoids help maintain sodium balance & blood pressure • Sex steroids regulate & maintain gametogenesis & reproductive function
Steroid Health Problems • The broad spectrum of physiological functions steroids control steroid over- or under- production are key features of many health problems: • Delayed or precocious growth or development • Diabetes • Abnormal immune response • High blood pressure or sodium imbalance • Female infertility, endometriosis, cystic ovaries, ovarian failure, hirsutism, early pregnancy loss, menopausal symptoms, osteoporosis, lactational failure • Male infertility, spermatogenic insufficiency, erectile dysfunction, prostatic hyperplasia • Reproductive cancers: breast, ovary, cervix, endometrium; testicular, prostate
Regressing Corpus Luteum trc.ucdavis.edu/mjguinan/apc100/modules/Reproductive/mammal/images/testis10.jpg www.vet.ksu.edu/media/images/therio/ov-structures/02.jpg Preovulatory Follicle anatomy.med.unsw.edu.au/cbl/embryo/Notes/images/week1/ovary/ovary.gif Gonadal Anatomy
http://www.urologyhealth.org/common/images/anatomy_AdrenalGland_coronal.jpghttp://www.urologyhealth.org/common/images/anatomy_AdrenalGland_coronal.jpg Sheep: http://arbl.cvmbs. colostate.edu/hbooks/pathphys/endocrine/adrenal/adrenal1.jpg & adrenal2.jpg Rhesus, Helly's fluid, H&E, 50 x: http:// www.vh.org/adult/provider/anatomy/ MicroscopicAnatomy/Images/Plate292.jpg Rhesus, Zenker's fluid, H&E, 612 x: http:// www.vh.org/adult/provider/anatomy/MicroscopicAnatomy/Images/Plate294.jpg Adrenal Anatomy
Chemistry of Steroid Hormones from University of Missouri - Rolla http://web.umr.edu/~nercal/teaching/chem363/chem363lec11chap26/
Cholesterol Metabolism: De Novo Synthesis http://www.cellml.org/examples/images/metabolic_models/cholesterol_biosynthesis.gif
Steroid Synthesis arbl.cvmbs.colostate.edu/hbooks/pathphys/endocrine/basics/steroidogenesis.gif
Gonadal Steroid Synthetic Paths Right & Center: Principle Paths in Leydig Cells, & Ovary
Steroid Synthetic Paths: Adrenal Cortex http://www.med.unibs.it/~marchesi/adrenalsteroidsynthesis.jpg
Hormone Levels with Age www.dpcweb.com/documents/news&views/spring_02/the_aging_male.html
Most steroids circulate in association with carrier proteins that increase their distribution volume & circulatory half-life. X-ray structure of SHBG with DHT: http://www.mdc-berlin.de/~crystal/ Structures/images/sex.jpg
But, it is only free steroid that can diffuse into target cells & bind to receptors that is bioactive.
Transcriptional Mechanism of Steroids http://www.aw-bc.com/mathews/ch23/fi23p16.gif
Steroid Receptors Bind HREs as Homo- or Heterodimers http://gibk26.bse.kyutech.ac.jp/jouhou/image/dna-protein/all/small_S1glu.gif
Receptor Binding to HREs Can Bend DNA & Alter Transcription http://gibk26.bse.kyutech.ac.jp/jouhou/image/dna-protein/all/small_S1run.gif
Enterohepatic Circulation involves Phase I & II enzymes in liver that increase hydrophilicity& water solubility.
Direct Links to Other Endocrine Axes Also help control PRL, TSH, & GH
Conclusions: Steroid metabolism is directly tied to many endocrine regulatory systems. While sex steroids are essential in maintaining species by controlling reproduction, they are dispensible.Corticoids are homeostatic, they control growth, development, immune function, carbohydrate metabolism, & ion balance.Endocrinologists will always be interested in steroids.
Acknowledgements Gainj Project The Gainj People Rees Midgley Al Hermalin Lora Myers Jim Wood Pat Johnson Ila Maslar Diana Lai Sam Refetoff Peter Smouse Peter Heywood Michael Alpers Brian Davison Yan Ren Lynne Shinto Diane Drinkwater Darryl Holman Bettina Shell Turkana Project All Turkana Subjects Mike Little Paul Leslie Ben Campbell Dhanesh Dookhran Kathy Whiteman Alexandra Evindar William Lukas Sandra Gray Jeanine Quigley Christine Sekadde -Kigondu Leah Kirumbi Related Studies Kathy O’Connor Coralie Munro Susannah Barsom Ellie Brindle Cheryl Stroud Kai Orton Jodiann Thompson Yefim Proshchitskiy Yelena Filipova Matt Lopresti Oliver Schultheiss Cheryl Frederick Steve Monfort Malcolm Potts David McClelland (dec) Support from: NSF, Umass/Boston, Sandia National Labs, Hybritech, Quidel, Monoclonal Antibodies Inc. (*in the lab at UMB)
Cellular Location: Cholesterol Synthesis Cholesterol de novo synthesis IIsoprenyl formation 2 NADPH 2 NADP HMG-CoAsynthase Thiolase HMG-CoAreductase 3-Hydroxy-3-methylglutaryl-CoA Acetoacetyl-CoA Science Slides: www.VisiScience.com Mevalonate Mevalonatekinase 3, 3-Dimethylalylpyrophosphate Isomerase ATP ADP Mevalonate-5-pyrophosphodecarboxylase Phosphomevalonatekinase ATP ATP ADP 5-Phosphomevalonate ADP 3-Isopentenylpyrophosphate 5-Pyrophosphomevalonate