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Testosterone is a C19 sex steroid hormone, that may be synthesized from:
Actions of testosterone include:
Testosterone can be further converted in certain tissues, via the enzyme 5-alpha reductase, into its more potent metabolite, dihydrotestosterone. Also some testosterone is converted into oestradiol in the liver, adipose tissue and the CNS (1). Also testosterone is converted to inactive metabolites in the liver, adipose tissue, muscle and kidney. Renal excretion is facilitated via conjugation of such metabolites to glucoronides in the liver.
Testosterone secretion in males follows a circadian rhythm, with a peak at 7-9 am and trough in late afternoon.