Normally, when testosterone levels get too high, the body detects this and prevents more being made. The hypothalamus instructs the pituitary gland to release luteinising hormone (LH) which prompts the Leydig cells in the testes to produce testosterone. Are declining testosterone levels not just a normal part of ageing? Their bloodwork shows testosterone in the low-normal range with cortisol at the upper end of normal or above. Because of its diverse role, low levels of testosterone can cause a wide range of symptoms including erectile dysfunction, low libido, and decreased muscle mass and strength. Testosterone levels drop naturally with age — but what’s a normal rate of decline? Sleep improves, which further supports testosterone production. Even a simple practice of five minutes of slow, deep breathing with extended exhales activates the parasympathetic nervous system and reduces acute cortisol levels. Clients who fix their sleep often see cortisol drop by 20 to 30 percent on follow-up bloodwork without any other intervention. Work stress, sleep deprivation, excessive screen time, overconsumption of caffeine, overtraining, and the constant stimulation of social media all drive cortisol production. A complex feedback system of hormones called the hypothalamic-pituitary-gonadal axis regulates your FSH levels. This is the hormone responsible for the physical changes of puberty (such as body hair growth and voice deepening) and the production of sperm. Follicle-stimulating hormone (FSH) is a hormone your pituitary gland makes and releases that plays a role in sexual development and reproduction. Prolactin appears to act directly on GnRH secreting neurons to block either synthesis or secretion of GnRH. GnRH secreted in a pulsatile manner by neurons with cell bodies in the hypothalamus.GnRH stimulates synthesis and glycosylation of beta subunits of FSH and LH. Testosterone from the testes also exerts negative feedback effects on FSH and LH production by negatively modulating production of GnRH in the hypothalamus. GnRH secreted in a pulsatile manner by neurons with cell bodies in the hypothalamus. Regulation of the hypothalamic pituitary unit is a complex process involving negative feedback mechanisms in the male. As with many hormones, GnRH has been called by various names in the medical literature over the decades since its existence was first inferred. An elevation of GnRH raises males' testosterone capacity beyond a male's natural testosterone level. Due to various challenges with measuring gonadotropin-releasing hormone levels, normal levels of this hormone are not well defined. It is challenging to measure gonadotropin-releasing hormone levels directly because it is released in short pulses throughout the day and metabolised in blood within minutes.2 If the body were an orchestra, hormones would be the conductors, orchestrating the symphony of bodily functions. In collaboration with testosterone inside the testes, which is triggered by LH, FSH also sustains sperm production. 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. This hormone is responsible for physical changes of puberty, like breast development and menstruation. In females, FSH and LH trigger their ovaries to begin producing estrogen. It does not release enough GnRH (gonadotropin-releasing hormone), so the pituitary never triggers testosterone or estrogen production. These gonadotropins are the luteinising hormone and the follicle-stimulating hormone, which stimulate the production of sex hormones such as testosterone. These hormones (gonadotropins) stimulate the production of testosterone, estrogen and progesterone. Your body’s production of gonadotropin-releasing hormone (GnRH) affects your sex hormone levels, libido and fertility. Data for gender-affirming care represents the number of adolescents actively receiving these medications (orange). For uterine fibroids, endometriosis, and central precocious puberty (CPP), the bars represent the number of people currently living with the conditions (blue). Comparison of population eligibility and active use of GnRH medications (per 100,000). GnRH medications are given as an injection every one to three months for gynecological conditions or targeted injections in an IVF cycle (Swayzer & Gerriets 2023, Yang et al. 2021). Administration of exogenous androgen results in growth of sex accessory organs. Decreased secretion of FSH and LH results in lack of stimulation of spermatogenesis and decrease secretion of androgens. Administration of exogenous GnRH will stimulate the secretion of FSH and LH. Increased GnRH stimulus gonadotropes of the anterior pituitary gland to secrete increased amounts of FSH and LH. Stress causes certain neurons with cell bodies in the cerebral cortex of the brain to secrete increased amounts of inhibitory neurotransmitters such as norepinephrine and beta endorphin and opioid peptide. Stress either physical mental or emotional can inhibit function of the hypothalamic pituitarytesticular axis. Negative modulation of GnRH secretion results in diminished FSH and LH secretion with a greater inhibition of LH secretion.
