[Bioforum] DHEA and thermogenesis... evolution of mammals

James Michael Howard jmhoward at anthropogeny.com
Sun Jun 12 15:40:19 EST 2005


 
...DHEA and thermogenesis...

Physiol Res. 2005 May 24; [Epub ahead of print]		 

Steroids and thermogenesis.

Hampl R, Starka L, Jansky L.

Institute of Endocrinology, Narodni 8, 116 94 Prague l, Czech Republic

Apart from thyroid hormones, as the main hormonal regulators of obligatory
thermogenesis and catecholamines, as major hormonal regulators of facultative
thermogenesis, production of heat in homeothermsis can be also influenced by
steroids. Generally, hormones can influence heat production by regulating
activity of various enzymes of oxidative metabolism, by modulating membrane
protein carriers and other membrane- or nuclear protein factors. Proton carriers
in the inner mitochondrial membrane, known as uncoupling proteins play the key
role in heat dissipation to the detriment of the formation of energy-rich
phosphates. In this minireview we have focused on the effects of steroids and
thyroid hormones on heat production in brown adipose tissues and in skeletal
muscles, with particular respect to their effect on uncoupling protein
expression. Apart from hormonal steroids, dehydroepiandrosterone, an important
precursor in the metabolic pathway leading to hormonal steroids which possess
many, mostly beneficial effects on human health, modulates metabolic pathways
which may lead to increased heat production. Recent studies demonstrate that
7-oxo-dehydroepiandrosterone, one of its 7-oxygenated metabolites is even more
effective than dehydroepiandrosterone. Recent findings of various actions of
these steroids support the view that they also may participate in modulating
thermogenic effects.


See "Hormones and Mammalian Evolution," www.anthropogeny.com/evolution.html 



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