Phyisology of the Pituitary Gland 001

Phyisology of the Pituitary Gland 001

water fasting weight loss

FIRST HORMONES OF THE ANTERIOR PITUITARY GLAND

The anterior pituitary, or adenohypophysis, plays a central role in the regulation of endocrine function through the tropic hormones. The production of tropic hormones, is under hypothalamic regulation by the hypophysiotropic neuropeptides released in the median eminence The tropic hormones produced by the anterior pituitary are released into the systemic circulation, from where they reach their target organs to produce a physiologic response, most frequently involving the release of a target organ hormone. The hormones produced by the target organs affect anterior pituitary function as well as the release of hypophysiotropic neuropeptides, maintaining an integrated feedback control system of endocrine function⁽³⁸⁾.

The hormones of the anterior pituitary can be classified into 3 families: the glycoproteins, those derived from proopiomelanocortin (POMC), and those belonging to the GH and prolactin family.

I- Glycoproteins:

They include TSH, FSH, LH, and human chorionic gonadotropin produced by the placenta. These hormones are heterodimeric glycoproteins consisting of a common subunit and a unique subunit, which confers the biologic specificity of each hormone.

1.      Thyroid-Stimulating Hormone :

TSH is a glycoprotein synthesized and secreted from thyrotrophs of the anterior pituitary gland.. They synthesize and release TSH in response to thyrotropin-releasing hormone (TRH) stimulation. TRH is synthesized in the paraventricular nuclei of the hypothalamus,. TRH binds to a protein-coupled receptor, which· activates phospholipase C, leading to increased phosphoinositide turnover, calcium mobilization, formation of cyclic adenosine monophosphate (cAMP), and release of TSH into the circulation. TSH binds to a protein-coupled receptor in the thyroid gland, activating adenylate cyclase, which leads to increased intracellular cAMP formation. TSH stimulates all the events involved in thyroid hormone synthesis and release. In addition, it acts as a growth and survival factor for the thyroid gland. The release of TSH from the anterior pituitary gland is under negative feedback inhibition by thyroid hormone.       

Posted in: fasting,fasting weight loss,loss,water,water fasting,water fasting weight,water fasting weight loss,weight,weight loss water