Tumor tissue, mass spectrometric

In men, 80% of testosterone is produced by the testes. In women, testosterone is produced by ovaries, the adrenals, and in peripheral tissue. Plasma testosterone is an indicator of endocrine testis function. It serves as marker for androgen-producing tumors or is elevated in female hirsutism. Mass-spectrometrically determined concentrations of plasma androstenedione in normal children and adolescents have been published by our group [49,50]. 

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