The conjugates of testosterone and its hepatic metabolites are released from the liver into circulation and excreted in the urine and bile. It is bound 65% to sex hormone-binding globulin (SHBG) and 33% bound weakly to albumin. The amount of testosterone synthesized is regulated by the hypothalamic–pituitary–testicular axis (Figure 2). The male generative glands also contain Sertoli cells, which require testosterone for spermatogenesis. Special cells (called Leydig cells) in your testicles make this hormone. It’s treatable with testosterone replacement therapy. Consequently, the pituitary gland goes into overdrive, producing very high levels of both LH and FSH in a futile attempt to jumpstart the ovaries. In women, LH is the hormone responsible for triggering ovulation, the pivotal moment when a mature egg is released from the ovary. If you experience symptoms of a pituitary adenoma and/or hormonal imbalance, it’s important to talk to your healthcare provider. Progesterone production then decreases and the next menstrual cycle begins — you get your period — when FSH levels start to rise again. As the follicles increase in size, they begin to release estrogen and a low level of progesterone into your blood. In males, FSH and LH work together to trigger their testes to begin producing testosterone. This begins the changes toward sexual maturity and development. As puberty approaches (usually between ages 10 and 14), the hypothalamus produces gonadotropin-releasing hormone (GnRH), which triggers FSH and LH. These hormone levels peak midpregnancy as the first ovarian follicle or seminiferous tubule (coiled tubules within the testes) mature in the fetus. Hormones are chemicals that coordinate different functions in your body by carrying messages through your blood to your organs, muscles and other tissues. It's one of several androgens (male sex hormones) in females. Signals sent from the brain to the pituitary gland at the base of the brain control the production of testosterone in men. The levels of GnRH are regulated through a negative feedback loop; high levels of reproductive hormones inhibit the release of GnRH. The release of ACTH is regulated by the corticotropin-releasing hormone (CRH) from the hypothalamus in response to normal physiologic rhythms. TSH is released from the anterior pituitary in response to thyrotropin-releasing hormone (TRH) from the hypothalamus. In female adults, high levels of testosterone may be a sign of polycystic ovary syndrome (PCOS). High levels of testosterone in female infants may lead to enlargement of their clitoris that can look almost like a penis. Excess testosterone affects your body differently depending on your sex and age.
