102.8 MB (3.9 MB compressed)
6614 x 5433 pixels
55.9 x 46.0 cm ⏐ 22.0 x 18.1 in (300dpi)
JACOPIN / BSIP / SCIENCE PHOTO LIBRARY JACOPIN / BSIP / SCIENCE PHOTO LIBRARY
Illustration of male hormone control, a constant regulation. The hypothalamo-hypophyseal axis : the LHRH (or GnRH) gonadotropin-releasing hormone (GnRH) released in the hypothalamus causes the hypophyseal secretion of two gonadotropin hormones (LH and FSH). The gonadotropic axis : FSH and LH, in acting on the testicles, maintains a constant concentration of testosterone, and therefore male sexual characteristics. Testosterone in turn limits secretions of GnRH, FSH and LH. The adrenocortical, under the control of a hypophyseal hormone (ACTH), produces a group of hormones called corticosteroids which include sexual hormones (androgens) that discretely intervene in sexual development and reproduction, but can also play an important role during pathological.
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