Adrenal Gland Cortisol and V.M.A

corticosteroids

ACTH ACTH (Adrenocorticotropic hormone) or corticotropin. Is a 39 amino acid peptide hormone (MW=4500) secreted by the pituitary to regulate the production of steroid hormones by the adrenal cortex. Steroid hormons by adrenal cortex

ACTH secretion from the anterior pituitary is controlled by both a classical negative feedback control mechanism and CNS-stress mediated control system. Various types of stress or pain perceived in higher levels of the brain modulate secretion of the hypothalamic neurosecretory hormone, corticotropin releasing hormone (CRH), a 41-amino acid peptide. CRH stimulates pituitary ACTH secretion. The second peptide that modulates ACTH secretion is vasopressin (AVP). AVP secretion is also stimulated by stress and acts synergistically with CRH to increase ACTH secretion in the pituitary portal circulation.

Cortisol and cortisone?

ACTH increases the synthesis and release of all adrenal sterioids, aldosterone, cortisol and adrenal androgens. It is the principal modulator of cortisol, the most important glucocorticoid in man. As the cortisol level in blood increases, release of ACTH is inhibited directly at the pituitary level. Through this same mechanism, decreasing cortisol levels lead to elevated ACTH levels.

Cortisol Physiologically effective in anti-inflammatory activity and blood pressure maintainace, cortisol is also involved in gluconeogensis. Cortisol is probably the most measured analyte for evaluating adrenal function although aldosterone and rennin are also ordered frequently.

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Primary aldosteronism is being increasingly investigated as a possible secondary cause of hypertension in adults. From the laboratory perspective, this usually involves measuring both aldosterone and renin and calculating aldosterone to renin ratio.

The determination of ACTH should be performed on EDTA plasma. To assay the specimen in duplicate, 400 μL of EDTA plasma is required.

Cortisol Cortisol the glucocorticoid found in the largest concentration in the serum, is the one usually measured to gain information about the functioning of the adrenal cortex. Plasma cortisol has a diurnal variation, its levels being higher in the morning than in the evening. Baseline readings are taken in the morning with the clinet at rest. تغير التركيز خلال ساعات النهار

Increased amounts of ACTH and cortisol are secreted independently of the circadian rthyme in response to physical and psychological stress. Elevated cortisol levels and lack of diurnal variation have been identified in patients with cushings disease Elevated circulating cortisol levels have also been identified in patients with adrenal tumors

Low cortisol levels are found in primary adrenal inufficiency as adrenal hypoplasia, congenital adrenal hyperplasia or addisson’s disease and in ACTH defeciency. ?

The timing of the cortisol levels with suppression and stimulation are determined by the procedure of the particular laboratory. Due to the normal circadian variation of cortisol levels distinguishing normal and abnormally low cortisol level =s can be difficult. Therefore, various tests to evaluate the pituitary adrenal axis ACTH-cortisol, including insulin-induced hypoglycemia, short and long term ACTH stimulation, CRF stimulation and artificial blockage of cortisol synthesis with metronome have been performed. Saliva measure free preferred ممكن من اليورن

While the assessment of cortisol in sweat or tears is only of theoretical importance and urinary cortisol of decreasing interest, salivary cortisol has become an invaluable tool for both basic scientists and clinicians. A number of significant advantages over the assessment of cortisol in blood has resulted in an steadily increasing interest in salivary cortisol. Free cortisol in saliva

Q: Does the concentration of cortisol in saliva accurately reflect the level in blood? A:Yes, when compared to the amount of unbound cortisol in serum or plasma samples. A number of studies have revealed correlations between the two specimen of r > 0.90. However, the correlation between the total cortisol levels in blood and salivary cortisol is usually weaker due to different amounts of CBG found in blood (e.g., high levels of CBG due to oral contraceptive use results in high total cortisol levels; free cortisol levels are usually unaltered in states of increased CBG). Unbound= free

Q: Does the salivary cortisol levels depend on saliva flow rate? A:No. Studies looking at salivary cortisol levels obtained under minimal and maximal flow rate clearly showed that the cortisol levels in saliva do not depend on flow rate لا يوجد علاقة بين كمية اللعاب التي يتم انتاجها و تركيز الكورتيزول

Preparation of client: The specimen is usually drawn in the morning after the client has been fasting. Evening samples may also require about 3 hour of fasting. Water is allowed. Because activity increases the level, the client needs to be supine for 2 hour before the test. Cortisol is excreted primarily in urine in an unbound free form Salivary cortisol: For research studies, salivary cortisol is simple noninvasive way to obtain a physiological index of stress.

You may be asked to avoid strenuous physical activity the day before the test. Be sure to drink enough fluids during the 24-hour urine test. This prevents dehydration . Many medicines may change the results of this test. Be sure to tell your doctor about all the non-prescription and prescription medicines you take. Talk to your doctor about any concerns you have regarding the need for the test, its risks, how it will be done, or what the results will mean L dopa affect cortisol conc

Increased serum cortisol level significance: an increase in cortisol can either ACTH-dependent or ACTH- independent. The specific medical treatment of elevated cortisol levels depends on the cause. The client may undergo a battern of tests to determine whether there is a tumor of the pituitary gland or of the adrenal gland. Decrease serum cortisol level clinical significance: the lack of cortisol in the serum may be due to primary hypofunction of the adrenal cortex, or it may be secondary to hypo functioning of the pituitary gland.

Once the symptoms of a lack of cortisol and aldosterone are recognized and confirmed, replacement therapy is started. Until the hormones are replaced, or when the need is greater than the supply, these clients may have problems related to the lack of cortisol and aldosterone.

Cortisone is a synthetic version of cortisol Cortisol and cortisone are both steroids. They share a similar core chemical structure which is common to all the cholesterol-like molecules. They comprise 4 fused carbon rings and, therefore, have a very rigid structure. The difference between cortisol and cortisone lies in the difference of the functional groups present in the two molecules. When the adrenal glands do not make enough cortisol, this is called adrenal insufficiency, the treatment is hydrcortison الادوية الستيرويدية تؤثر على تركيز الكورتيزول

V.M.A Generally, unfortunately most of the hormones are present in blood in such small amounts that their measurement is very difficult. Some of hormones or their metabolites are excreted in the urine and in many instances their concentration in urine is much greater than in blood. Since it is much easier to obtain a few hundred milliliters of urine, than, say,20 ml of blood, some hormone analysis may be done with urine. Since the hormone excretion rate may vary during the day. The use of a 24 hour urine specimen gives more accurate results. يضع الكونتينر اللي بحمع فيه بالتلاجة

Not all hormones are excreted in the urine in appreciable amounts, those of lower molecular weight, e.g. the steroids, are more likely to be found in the urine in measurable amounts than are larger molecules such as the pituitary hormones. In some instances the hormone itself may not be excreted in the urine in large quantities, but various metabolites of the hormone may be found. The measurement of these metabolites sometimes gives satisfactory estimate of the amount of original hormone present in the blood.

Vanillylmandelic Acid, 24 hr urine. Vanillylmandelic acid (VMA) is one of the metabolites of the catecholamines epinephrine (adrenaline) and norepinephrine. This test measures the amount of VMA that is excreted into the urine, typically over a 24-hour period, to detect excess catecholamine production.

Useful For Screening children for catecholamine-secreting tumors.   Supporting a diagnosis of neuroblastoma Monitoring patients with a treated neuroblastoma The measurement of urinary metanephrines plus VMA have been suggested as the best screening procedure for the detection of pheochromocytomas. Pheochromocytoma tumor located in one or both of the adrenal glands that releases excess hormones called catecholamines (e.g., dopamine, epinephrine (adrenaline), norepinephrine and their metabolites, such as metanephrines) Metanephrin a metabolite of epinephrine(adrenaline)

VMA is usually present in the urine in small fluctuating amounts that only increase appreciably during and shortly after the body is exposed to a stressor. (24 hr is the best) Neuroblastomas, pheochromocytomas, and other neuroendocrine tumors, however, can produce large amounts of catecholamines, resulting in greatly increased concentrations of the hormones and their metabolites. The hormone releases can cause persistent hypertension, severe headaches, palpitations, sweating, nausea, anxiety, and tingling in the extremities.

patient Preparation Abstain from medications for 72 hours prior to collection.   Collect 24-hour or random urine. Refrigerate 24-hour specimens during collection.     Storage/Transport Temperature Refrigerated.   Unacceptable Conditions: Specimen types other than urine.   Stability Ambient: Unacceptable; Refrigerated: 1 week; Frozen: 2 weeks  

Homework  dehydroepiandrosterone(DHEA)