The adrenal gland, as well as the pituitary gland, consists of two portions: the medullary portion occupies ¼ of the mass of the gland and is made up of modified sympathetic ganglion cells that secrete catecholamines; the adrenal cortex constitutes ¾ of the gland and secretes different types of hormones The adrenal cortex secretes three main types of steroid hormones: aldosterone, also called mineralocorticoid for its effects on the minerals sodium and potassium; the glucocorticoids so called for their ability to increase the plasma concentration of glucose, the main one being cortisol; and sex hormones, in particular androgens prevalent in the male. All steroid hormones are synthesized from cholesterol, which is modified by various enzymes to become aldosterone, glucocorticoid hormones or sex hormones.
Hypothalamic-pituitary-adrenal axis, these three organs work in synchrony to ensure a correct stimulatory chain, so as to produce or inhibit the synthesis of glucocorticoids or mineralocorticoids.
Steroid hormones - being fat-soluble in nature - interact with intracellular receptors, so alterations at the transcriptional level can modify or reduce these receptors and slow down the pharmacological response. In summary, the most important functions of the steroid hormones produced by the adrenal gland: increase in blood sugar through gluconeogenesis in the liver or lipolysis in adipocytic cells (control of opposites, when this regulation is misled by too high dosages of glucocorticoids there is accumulation of fat in particular areas of the body, neck, face and supra-clavicular area); they increase the absorption of sodium ions, while I favor the escape of potassium ions and hydrogen ions, thus causing widespread water retention. These functions are all aimed at providing ready energy to the organism in unfavorable conditions.
However, it must be remembered that a prolonged depletion of energy reserves can lead to unpleasant catabolic effects on lymphatic, connective, muscular, adipose, skin and bone tissue, which coincide with the adverse effects of this pharmacological category.
Although the side effects are not negligible, the glycorticoid drugs are widely used thanks to their anti-inflammatory action, more powerful than that carried out by NSAIDs. The anti-inflammatory activity is achieved thanks to a synergy of effects at different levels:
- Inhibition of phospholipase A2, this enzyme is also involved in the very early stages of the arachidonic acid pathway, so its inhibition coincides with the blocking of both enzymatic pathways, that of cyclooxygenase and that of lipoxygenase;
- Inhibition of COX2 gene transcription;
- Reduction of the activity of T and B lymphocytes, with reduction of the production of antibodies, cytokines and growth factors;
- Blocking the release of important pro-inflammatory chemical mediators, such as histamine and bradykinin;
- The antibacterial activity is inhibited, but not the phagocytic activity, so the pathogens remain latent;
- They favor the onset of osteoporosis, since they increase the activity of the osteoblasts and reduce that of the osteoclasts;
- They reduce the activity of important immune cells, such as neutrophils and macrophages.
On the basis of their duration of action, glucocorticoid drugs are classified into short, intermediate or long-acting glucocorticoids; all show an excellent anti-inflammatory effect, but to date pharmacologists have not been able to separate the pharmacological activity from that metabolic.
In addition to being anti-inflammatory, glucocorticoids are also used to treat:
Acute and chronic adrenal insufficiency, better known as Addison's disease (hyperpigmentation, fatigue, weight loss and hypotension);
Congenital adrenal hyperplasia, a pathology characterized by a lack of enzymes involved in the synthesis of corticosteroids, by hypertrophy of the adrenal gland in favor of the synthesis of androgens; it is pharmacologically treated with cortisol;
Cushing's syndrome, a pathology due to an excess of glucocorticoids, in turn caused by a pituitary edema or a tumor; for this reason it is necessary to intervene surgically by removing the gland: drug treatment with cortisol follows afterwards;
allergic reactions; vascular collagen disorders; eye diseases; gastrointestinal disorders; bone and joint inflammation; organ transplants; bronchial asthma; skin diseases.
In all the cases listed, these are systemic and non-curative therapies, with low dosages and for short periods; special dosage methods are necessary in case of topical therapies, ophthalmic preparations, intra-articular injections, enemas for ulcerative colitis, aerosols and nasal sprays.
The side effects of glucocorticoid drugs are, in the most serious cases, iatrogenic Cushing's Syndrome, hirsutism (appearance of more hairs on the skin), blockage of the adrenal-pituitary axis, for this reason it is very important to gradually stop the therapy; generally there is simply water retention and widespread swelling.
Other articles on "Glucocorticoids"
- NSAIDs: side effects
- Allergies
