SEMINAR: Plasma steroid-binding proteins: Gatekeepers of steroid hormone action
|Plasma steroid-binding proteins: Gatekeepers of steroid hormone action : School of Human Sciences (APHB) Seminar Series
The Seminar: Biologically active steroids are transported in the blood by albumin, sex hormone-binding globulin (SHBG) and corticosteroid-binding globulin (CBG). These plasma proteins also regulate the non-protein-bound or "free" fractions of circulating steroid hormones that are considered to be biologically active; as such, they can be viewed as the “primary gatekeepers of steroid action”.
Albumin binds steroids with limited specificity and low affinity but its high concentration in blood buffers major fluctuations in steroid concentrations and their free fractions. By contrast, SHBG and CBG play much more dynamic roles in controlling steroid access to target tissues and cells. They bind steroids with high (~nM) affinity and specificity, with SHBG binding androgens and estrogens and CBG binding glucocorticoids and progesterone. Both are glycoproteins but are structurally unrelated, and they function in different ways that extend beyond their transportation or buffering functions in the blood.
Plasma SHBG and CBG production by the liver varies during development and different physiological or pathophysiological conditions, and abnormalities in the plasma levels of SHBG and CBG or their abilities to bind steroids are associated with a variety of pathologies. Understanding how the unique structures of SHBG and CBG determine their specialized functions, how changes in their plasma levels are controlled, and how they function outside the blood circulation provides insight into how they control the freedom of steroids to act in health and disease.
The Speaker: Geoffrey Hammond obtained an MSc in Steroid Endocrinology from the University of Leeds, and a Ph.D. in Biochemistry from the University of Oulu, Finland. After postdoctoral training at the University of California San Francisco, he joined the University of Manchester to establish his research program with a grant from the MRC (UK). Dr. Hammond moved to Canada in 1984, where he held appointments in the Departments of Obstetrics & Gynecology, Pharmacology & Toxicology, and Oncology at the University of Western Ontario. In 2002, he was recruited by The University of British Columbia and served as the Scientific Director of the Child & Family Research Institute until 2012, when he was appointed as Professor and Head of the Department of Cellular & Physiological Sciences.
Professor Hammond has had a longstanding interest in endocrinology in general and the ways that steroid hormones function in particular. Steroid hormones control normal biological processes, but are implicated in many diseases, including reproductive disorders, inflammation, diabetes, cardiovascular disease, and hormone-dependent cancers of male and female reproductive tissues. The way steroids gain access to their target tissues is poorly understood, but this process is influenced primarily by two high affinity steroid-binding proteins in the blood: corticosteroid binding globulin and sex hormone-binding globulin. These two plasma proteins bind the glucocorticoids and the sex steroids (androgens and estrogens), respectively. Through a combination of molecular biological, biochemical, and physiological approaches, Professor Hammond and his trainees have defined how these steroid-binding proteins are produced and function with respect to normal development and aging, as well as in disease processes.
In recognition of his contributions to our understanding of extracellular steroid-binding proteins, Professor Hammond received the Society for Endocrinology International Medal in 2105. He has published more than 200 scientific articles; held several patents and has collaborated extensively with the diagnostic and pharmaceutical industries.
Professor Geoffrey Hammond, Cellular & Physiological Sciences, University of British Colombia
Seminar room 1.81 (first floor) Anatomy building, The University of Western Australia
: 6488 3313
Tue, 28 Feb 2017 13:00
Tue, 28 Feb 2017 14:00
Deborah Hull <[email protected]>
Mon, 27 Feb 2017 14:56
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