Hormones adrenocorticotropic hormone

The regulation of glucocorticoid secretion is accomplished by the pituitary hormone, adrenocorticotropic hormone (ACTH). Under normal conditions, ACTH is released from the anterior pituitary in response to corticotropin-releasing hormone (CRH), which is secreted by the median eminence of the hypothalamus (Fig. 74—3). 

Functional pituitary adenomas can be found to express a variety of hormones, such as growth hormone, prolactin, thyroid-stimulating hormone, adrenocorticotropic hormone, or follicle-stimulating hormone. 

The anterior lobe of the pituitary secretes growth hormone, thyroid-stimulating hormone, adrenocorticotropic hormone or ACTH, follicle-stimulating hormone and luteinizing hormones, melanocyte-stimulating hormone, and endorphins. 

Growth hormone Thyroid-stimulating hormone Adrenocorticotropic hormone Prolactin... 

In the anterior pituitary gland (see Hormones, anteriorpituitaryhormones), both adrenocorticotropic hormones (ACTH) and the endogenous opiate hormone, P-endorphin, are synthesized from a common prohormone (2) (see Opioids,endogenous). In the adrenal medulla, five to seven copies of another opiate hormone, methionine—enkephalin (Met-enkephalin), and one copy of leucine—enkephalin (Leu-enkephalin) are synthesized from each precursor molecule (3). 

In humans, the hypothalamic-derived protein and the hormone noncovalent complexes are packaged in neurosecretory granules, then migrate along axons at a rate of 1 4 mm/h until they reach the posterior pituitary where they are stored prior to release into the bloodstream by exocytosis (67). Considerable evidence suggests that posterior pituitary hormones function as neurotransmitters (68) vasopressin acts on the anterior pituitary to release adrenocorticotropic hormone [9002-60-2] (ACTH) (69) as well as on traditional target tissues such as kidneys. Both hormones promote other important central nervous system (CNS) effects (9,70). 

Pregnenolone is transported from the mitochondria to the ER, where a hydroxyl oxidation and migration of the double bond yield progesterone. Pregnenolone synthesis in the adrenal cortex is activated by adrenocorticotropic hormone (ACTH), a peptide of 39 amino acid residues secreted by the anterior pituitary gland. 

Drugs with unknown mechanism of action are gabapentin, bromides (but see above effects on GABAergic transmission) and adrenocorticotropic hormone (ACTH), which is used in infantile spasms. 

Adrenocorticotrope Hormone (ACTH) Gluco-mineralocorticoid Receptors... 

Proopiomelanocortin (POMC) is the precursor peptide of hormones and neuropeptides expressed in the pituitary and the hypothalamus (adrenocorticotropic hormone (ACTH), lipotropin, a-melanocyte-stimulating hormone (aMSH), yMSH, 3-endorphin, and others). The main clinical consequences of POMC deficiency are adrenal insufficiency (due to absence of ACTH), red hair pigmentation (due to absence of MSH) and severe early-onset obesity (due to the lack of aMSH). 

Otfier fiormones accelerate tfie release of free fatty acids from adipose tissue and raise tfie plasma free fatty acid concentration by increasing the rate of lipolysis of the triacylglycerol stores (Figure 25—8). These include epinephrine, norepinephrine, glucagon, adrenocorticotropic hormone (ACTH), a- and P-melanocyte-stimulat-ing hormones (MSH), thyroid-stimulating hormone (TSH), growth hormone (GH), and vasopressin. Many of these activate the hormone-sensitive hpase. For an optimal effect, most of these lipolytic processes require the presence of glucocorticoids and thyroid hormones. These hormones act in a facilitatory or permissive capacity with respect to other lipolytic endocrine factors. 

FIGURE 10-3. Expected neurohumoral response to hypovolemia. ACTH, adrenocorticotropic hormone ADH, antidiuretic hormone CNS, central nervous system Na, sodium. (Reprinted from Jimenez EJ. Shock. In Civetta JM, Taylor RW, Kirby RR, eds. Critical Care. New York Lippincott-Raven 1997 369, with permission.)... 

Corticosteroids hasten functional recovery after relapses.27 Intravenous adrenocorticotropic hormone, intravenous methylprednisolone, or oral prednisone are used for treatment of relapses. Generally, intravenous methylprednisolone is considered the drug of choice for acute relapses.28... 

Pharmacotherapy generally is reserved for patients (1) in whom the ectopic adrenocorticotropic hormone-secreting tumor cannot be localized (2) who are not surgical candidates (3) who have failed surgery (4) who have had a relapse after surgery or (5) in whom adjunctive therapy is required to achieve complete remission. 

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