Abstract
The review presents the fundamental information on the metabolism of dehydroepiandrosterone (DHEA), its biological role and possibilities of its use for replacement therapy. There were studied species differences in the synthesis of DHEA in the adrenal cortex. It was found that DHEA and DHEA-sulfate are produced only by the adrenal glands of humans and monkeys, including lower monkeys. Their biosynthesis involves the following steps: cholesterol → pregnenolone → 17-hydroxypregnenolone → DHEA. The adrenal glands of other species, including rats and mice do not synthesize DHEA. At the same time, in certain brain structures not only in man and monkey, but also in other animals DHEA and its precursors are synthesized de novo which are denoted as neurosteroids. It was demonstrated that Purkinje cells which play an important role in memory formation and learning are mainly place neurosteroid formation in mammals and other vertebrates. To establish the relationship of age and the level of DHEA and other steroids we studied the dynamics of their levels at different periods of postnatal development of people. Peak concentration DHEA observed in aged 25–30 years. In the interval from 20 to 90 years in humans the level falls approximately for 90 %. Cortisol levels in blood does not vary with age, leading to an imbalance in the ratio of cortisol/DHEA. Proved a major role of DHEA as a source (precursor) for the synthesis of biologically active sex steroids – testosterone, estradiol and estrone in peripheral tissues. This review presents the bioavailability of DHEA in various physiological and pathological processes in humans and animals. In animal experiments has shown a higher bioavailability of DHEA in transdermal administration as compared with oral administration as in this case there is no steroid rapid inactivation in the liver during its first passage. According to recent studies there is a pronounced dependence of bioavailability of DHEA during replacement therapy from the method of drug administration.
Highlights
The review presents the fundamental information on the metabolism of dehydroepiandrosterone (DHEA), its biological role and possibilities of its use for replacement therapy
In certain brain structures in man and monkey, and in other animals DHEA and its precursors are synthesized de novo which are denoted as neurosteroids
To establish the relationship of age and the level of DHEA and other steroids we studied the dynamics of their levels at different periods of postnatal development of people
Summary
Для выяснения возрастной динамики циркулируэндокринной системы обусловлены тремя состояния- ющего ДГЭА и других стероидов у человека нами проми: высоким уровнем секретируемого гормона, низ- ведено изучение его уровня в различные периоды ким уровнем его продукции и изменением чувстви- постнатального развития, включая предельный биотельности к гормонам на уровне ткани-мишени. Необходимо подчеркнуть, что все приведенные в надпочечниках, попадая в кровь общей циркуляции, данные о величине трансформации ДГЭА основаны достигает периферических тканей, где внутри самих на значениях циркуляторных уровней гормонов, тогда клеток с помощью соответствующих ферментных сикак более значимое их количество образуется и нака- стем происходит его трансформация в биологически пливается в различных тканях, прежде всего в тканях- активные стероидные гормоны эстрадиол и/или тестомишенях и в жировой ткани. В условиях кастрации ного образования тестостерона и 5α-ДГТ не отражает- содержание в крови тестостерона у мужчин снижается ся на их показателях в крови, но их конъюгированные на 95 %, однако в этом случае уровень его метаболита метаболиты, перечисленные выше, являются опти- 5α-ДГТ, который образуется в простате и является мальными маркерами для оценки уровня андрогенов для нее активным гормоном, снижается менее драмаи их биологического действия у человека. Labrie его пула в простате играет локальное превращение провела клиническое исследование, в ходе которого ДГЭА и ДГЭАС в 5α-ДГТ
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
