Adrenal cortexGlucocorticoid GC is an adrenal steroid hormone that controls a variety of physiological processes such as glucocorticoid secreted by the adrenal cortex, immune glucocorticoid secreted by the adrenal cortex, cardiovascular activity, and brain function. In addition to GC induction in response to stress, even in relatively undisturbed states its circulating level is subjected to a robust daily variation with a peak around the onset of the active period of the day. It has long been believed that the synthesis and secretion glucocorticood GC are primarily regulated by the hypothalamus—pituitary—adrenal HPA neuroendocrine axis. However, recent chronobiological research strongly supports the idea that best test booster for libido 2015 regulatory mechanisms along with the classical HPA neuroendocrine axis underlie the diurnal rhythm of circulating GC. Most notably, recent studies demonstrate that the molecular circadian clockwork is heavily involved in the daily GC rhythm at multiple levels.
The Adrenal Glands
Production of all three classes is triggered by the secretion of ACTH from the anterior lobe of the pituitary. The glucocorticoids get their name from their effect of raising the level of blood sugar glucose. One way they do this is by stimulating gluconeogenesis in the liver: Cortisol and the other glucocorticoids also have a potent anti-inflammatory effect on the body. They depress the immune response, especially cell-mediated immune responses.
The mineralocorticoids get their name from their effect on mineral metabolism. The most important of them is the steroid aldosterone. Water follows the salt and this helps maintain normal blood pressure. In sexually-mature males, this source is so much lower than that of the testes that it is probably of little physiological significance.
However, excessive production of adrenal androgens can cause premature puberty in young boys. In females, the adrenal cortex is a major source of androgens. Their hypersecretion may produce a masculine pattern of body hair and cessation of menstruation. The essential role of the adrenal hormones means that a deficiency can be life-threatening.
Fortunately, replacement therapy with glucocorticoids and mineralocorticoids can permit a normal life. The adrenal medulla consists of masses of neurons that are part of the sympathetic branch of the autonomic nervous system. Instead of releasing their neurotransmitters at a synapse , these neurons release them into the blood.
Thus, although part of the nervous system, the adrenal medulla functions as an endocrine gland. Release of adrenaline and noradrenaline is triggered by nervous stimulation in response to physical or mental stress. The hormones bind to adrenergic receptors — transmembrane proteins in the plasma membrane of many cell types.
Link to graphic showing the location and structure of the adrenal glands 92K.