METHODS OF SIGNALLING

Steroid Hormones and Glucocorticoid methods of signalling

Steroid Hormones and Glucocorticoid methods of signalling

Introduction

Steroid hormones are chemical messengers produced from cholesterol and can, like all other hormones; influence the activity of groups more or less wide of the target cells. Because of this common origin, steroid hormones have the structure tetraciclica characteristic of cholesterol. 

Steroid hormones: in short

Mineralocorticoids

Steroid hormones that increase the re-absorption of water and sodium, promoting the excretion of potassium and hydrogen ions. Are therefore important in the presence of hypotension (low blood pressure), which increases blood volume. The synthesis of mineralocorticoids occurs in the zona glomerulosa (outer) of the adrenal cortex. The most prominent and active mineralocorticoid is the aldosterone. Main disease of excess: Conn's syndrome. Main pathology fault: primary adrenal insufficiency.

Glucocorticoids

Steroid hormones that have the purpose of raising the blood glucose, increasing the production of glucose from some amino acids and decreasing its use peripheral. These hormones also stimulate the deposition of glycogen in the liver and reduce the inflammatory response and immune. Are particularly important in the process of adaptation to intense physical stress. The synthesis of glucocorticoids occurs in areas fasciculata of the adrenal cortex and reticular. The most prominent and active is cholesterol. Main disease of excess: Cushing's syndrome. Main pathology defect: Addison's disease.

Androgen

Steroid hormones which influence the characteristics and capabilities male sex; have anabolic action especially at the level of the musculature and the bone tissue. In women, are secreted in much lower quantities than men. Androgens are synthesized by the interstitial cells of Leydig (testicular) and also in small amounts by the adrenal cortex (important for the female body). The most prominent and active is testosterone, which is then transformed into the potent androgen dihydrotestosterone in some tissues - such as prostate, external genitalia, and skin - which contain the enzyme 5a-riduttas.

Estrogen

Steroid hormones that affect female sexual characteristics and capabilities have anabolic action especially at the level of adipose tissue, bone, and muscle. Humans are secreted in much lower quantities than in women. Are synthesized from androgens by the enzyme aromatize, especially in the ovary, in the placenta during pregnancy and to a lesser extent in various tissues (especially in the adipose, which provides an important contribution in men and women after the menopause). The most prominent and active is the estradiol.

Progestins

Steroid hormones that affect female sexual characteristics and capabilities are important for the proper conduct of the menstrual cycle and pregnancy. The most prominent and active is progesterone, which is synthesized in many tissues, because precursor of the other classes of steroid hormones (Litwack, 2004, pp. 129-39).

Molecular mechanisms of glucocorticoid receptor signalling

In higher organisms, glucocorticoids synthesized by the adrenal cortex, play an important role in the adaptation to stressors and maintenance of internal homeostasis consecutive. The activation of the hypothalamic pituitary adrenal (HPA) axis by stressful Situations-from emotional stress to infection-, leads to Increase in plasma cortisol (in primates) / corticosterone (in rodents) Concentrations, Which in turn almost all physiological systems Affect in the ...