Determination corticosteroids and their metabolites in urine
Endocrinology / / May 21, 2016
Method for determination of free cortisol in the urine
H he most accurate method is the determination of free cortisol in the urine.Average its selection - from 0 to 150 micrograms per day.This method is due to certain technical difficulties yet found a small spread.
A method for the study of adrenocortical function by determining the rate of cortisol secretion.The method is based on determining the relative quantities of radioactive corticosteroids and their metabolites in urine after intravenous or oral administration of the labeled cortisol.
method Silber and Porter
widespread is the definition of urinary 17-gidroksikortikosteroidov method Silber and Porter.This reveals cortisol, cortisone, 11-deoxycortisol and tetrasoedineniya.further metabolic products (A and B and kortoly and in-kortolony, allokortoly and allokortolony) this method can not be opened.
Using this technique, the normal allocation of the total 17-gidroksikortikosteroidov ranges from 2 to 5 mg / 24 hours, including 0.02-0.
In determining urinary 17-ketogenic steroids, in addition to compounds called out by the reaction Silber - RIM Porter, reveals a number of other derivatives of cortisol and cortisone, and sometimes - cortisol precursors and pregnantriol.An advantage of the method is the possibility of using a single colored reaction determine the 17-keto steroids and 17-ketogenic steroids.Average allocation of 17-ketogenic steroids in women is 12 ± 5 mg per day for men - 15 ± 5 mg per day.
in 1963-1964.Metcalf suggested a simple and fast method to detect in urine all 17 glucocorticoids from 20-keto and 20-hydroxy (cortisol, cortisone, tetrahydrocortisol, tetragidrokortizon, A and B kortoly, A and B kortolony, allokortoly and allokortolony), as well as pregnantriol, and do not open the endogenous 17-keto steroids.Compared with the method of Silber and Porter level opened by Metcalf corticosteroids and higher amounts in healthy people 11,9 ± zh 3,6 mg / 24 hours for women and 16,7 ± 3,7 mg / 24 hours for men.
In assessing the results of determining allocation of 17 gidroksikortiko steroids in urine should be borne in mind that under certain pathological conditions urinary excretion of hormones and their metabolites can not match the level of their blood.Thus, selection 17, hyperthyroidism-hydro-ksikortikosteroidov increased and hypothyroidism - lowered, while 17 gidroksikortikosteroidov level in blood is normal in these diseases.
Definition of neutral 17-keto steroids (17-KS) in the urine
Definition of neutral 17-keto steroids (17-KS) in the urine is less valuable for evaluating the functional activity of the adrenal glands than the methods outlined above.17-keto steroids urine come from the 17-keto steroids produced by the adrenal cortex of testosterone produced by the testicles, and partly due to glucocorticoid.The 17-keto steroids 5-10% passes urine cortisol and cortisone 5%.In men, approximately 1/3 of the 17-keto steroids urine comes from the testicles.Thus, the definition of 17-keto steroids urine allows only indirectly judge the most important function of the adrenal cortex - the allocation of glucocorticoid.Separation of 17-ketosteroids and a- (5 fraction improves the diagnostic value of the COP-17 determination in urine. In the fraction constituting 10-15% of the total urinary 17-KS is derived from the adrenal cortex, but a fraction consists17-KS, produced as a by the adrenal glands and testes. Isolated increased (3 fractions 17-KS, for example, when adrenogenital syndrome, may indicate a relationship masculinization of the increased production of 17-keto steroids by the adrenal cortex.
diagnostic importance is the determination in the urinesome individual 17-COP. So, increased allocation of dehydroepiandrosterone observed in virilizing tumors of the adrenal cortex, which may be important in the differential diagnosis of tumors and other diseases associated with virilization.
More complicated is the fractionation of 17-KS with their division into 7 fractions. whenit is possible to isolate fractions of adrenal androgens and gonadal origin, and the fractions containing the glucocorticoid metabolites.
definite diagnostic value in certain diseases is defined in the urine pregnantriola.
Less common in clinical practice is made technically complex definition of aldosterone release urine.Average its isolation is 5-15 mg / 24 h.
All these methods are aimed at identifying the functions of the adrenal cortex "static."In some cases, more important are the methods to identify the functional reserves of the adrenal glands and establish the degree of dependence of the function of the adrenal cortex by stimulation of the pituitary.
To identify the ability of adrenal cortex to respond to stimulation by adrenocorticotropic hormone, various modifications of the samples with the introduction of ACTH.
Eosinophilic sample Thorn
most simple, though less accurate method of determining the functional reserves of the adrenal cortex is eosinophilic sample Thorn et al. The sample consists of intramuscular injection of 25 IU ACT D and run the absolute number of eosinophils in the blood before the introduction AKLT and through4 hours after administration.When sufficient functional adrenal reserves the number of eosinophils after administration of ACTH decreased by more than 50%.Coating is conducted by eosinophils Dungeru or Randolph, and other blood cells besides eosinophils dissolve.During the tests necessary to pay attention to the standard preparation of ACTH, lack of a depot action, the degree of cleaning and quick absorption.When the initial amount of eosinophils in less than 1 100 or more than 1000 mm3 to 1 mm, and the accuracy of the sample decreases.
sample with intravenous ACTH
most reliable, although in some cases unsafe, is a trial with intravenous administration of ACTH.Thus intravenous drip administered 25 IU ACTH for 8 hours in the case of normal adrenal response to stimulation with the number of eosinophils in the blood decreases by more than 50%, 17 gidroksikortikosteroidov excretion in urine increases by more than 100% (in most cases -. A 3-5 times);17 when determining gidroksikortikosteroidov increase their blood up to 40 micrograms / 100 ml at the end of six hours marked intravenous drip 25 IU ACTH.These samples can be used for the detection of primary adrenal insufficiency.
technically more simple and reliable enough sample, allowing to identify the functional reserves of the adrenal glands and establish the dependence of the adrenal function in certain pathological conditions of the regulation of the pituitary is ACTH test with prolonged action.Just as in the sample with intravenous ACTH have investigated individuals determined at least two times prior to the daily excretion of urine samples 17-CC gidroksikortikosteroidov 17, 17 gidroksikortikosteroidov content in the blood, the number of eosinophils in the blood.Depending on the particular laboratory capacity can be determined by all these indicators, or just some of them.
All these parameters are investigated again after intramuscular injection of long-acting ACTH.Cortisol levels in blood increases after 2 hours, and this rise is maintained for 8 hours. There are various modifications of this sample, which differ by the number of ACTH administered, time and duration of administration of the sample.Forsham recommends the introduction of 80-160 IU ACTH gel.Enough clear results obtained with the introduction of much lower doses of ACTH - 20-40 IU eksaktgina.The test results are interpreted in the same way as the results of tests with intravenous injection of ACTH.It must be borne in mind that in any case, the sample must be assessed only on the basis of own control studies.
In some cases, when the function of the adrenal cortex was long suppressed in the absence of adrenocorticotropic stimulation (eg, after prolonged steroid therapy, the presence of a tumor of the adrenal cortex, and so on. P.), ACTH stimulation for 8 hours when administered intravenously or 24h when administered long-acting ACTH is not enough to obtain the response of the adrenal glands.In this case, you can apply a longer stimulation for 48-72 hours.
With the introduction of trial with intravenous administration of ACTH or with the use of long-acting ACTH in patients with severe chronic insufficiency of the adrenal cortex acute adrenal insufficiency may develop, which is associated with the depletion of functional reservesadrenal glands, so the sample must be carried out in a hospital environment.If there is a clear sample of chronic insufficiency of the adrenal glands are made against the background of glucocorticoid replacement therapy or their synthetic analogs.There is also a risk of anaphylactic reactions to ACTH.
sample to suppress adrenocorticotropic function of the anterior pituitary
Another group of samples is aimed at the suppression of adrenocorticotropic function of the anterior pituitary.To suppress adrenocorticotropic function of the adrenal cortex used drugs with glikokortikoidnoy activity - cortisol, cortisone, prednisolone, prednisone, dexamethasone.The biggest advantage has dexamethasone, which in small doses has a strong inhibitory effect on the release of ACTH by the anterior pituitary;wherein the amount of drug administered for diagnostic purposes, is so small that it is practically no effect on the concentration of glucocorticoids in the blood and urine on their allocation.
sample is carried out as follows: Up to twice the sample is determined by the daily urinary 17-KS (or - in patients Ytsenko syndrome - Cushing - 17 gidroksikortikosteroidov), then for 3 days on a daily basis give dexamethasone at 0.5 mg every 6 hours on the third.day collect urine and determine the daily allocation of 17-or 17-keto steroids glucocorticoids.If an increased allocation of appropriate steroid dependent on increased adrenocorticotropic stimulation and dientsefalo-pituitary system normally reacts to the inhibitory effect of glucocorticoid, their daily excretion is reduced by at least 50%.Patients with tumors producing increased amounts of hormones and to a certain extent independent of adrenocorticotropic stimulation significant decrease release of hormones and their metabolites is usually does not occur.The syndrome pituitary - adrenal hyperplasia with Cushing for suppressing adrenocorticotropic pituitary activity, require large doses of dexamethasone - 8 mg per day (2 mg every 6 hours orally).
When used cortisone last sample 100 mg is administered for 10 days, and the use of prednisolone - 20 mg for 7-10 days.Cortisone and prednisone are used successfully at virilnoe syndromes when allocation is determined by a decrease in the COP-17.
Test with metapyron (SU-4885)
recommended test with metapyron (SU-4885) to clarify the provisions of adrenocorticotropic anterior pituitary, as well as samples, which is determined by the increased levels of cortisol in the blood after administration of bacterial pyrogens.
indirectly the functional state of the adrenal cortex to judge the study of water-salt metabolism.
Decrease in blood sodium levels below 300-315 mg% (130-142 mEq / l) and increased potassium levels above 20-22 mg% (6.5 meq / l) indicates the lowering of mineralocorticoid adrenocortical function.With increased mineralocorticoid function of the adrenal cortex are coming backward shift - lowering potassium and sodium levels increase.Attaches importance to the ratio of sodium / potassium in serum.This ratio (sodium and potassium are determined meq) under normal conditions is equal to 30-32.Ratio of less than 30 lets think of adrenal insufficiency, the ratio is greater than 32 can be found at hyperaldosteronism.
Determination of sodium and potassium in the saliva
diagnostic value give the definition of sodium and potassium in the saliva.Increased allocation of sodium and potassium decrease saliva indicates a lack of mineralocorticoid adrenal function.Particular importance is given to change the ratio of sodium / potassium in saliva.Normally, the ratio (in meq) ranges 0,6-2,1- Values above 2.1 indicate adrenal insufficiency, below 0.6 - about hyperaldosteronism.
To reveal hidden adrenal insufficiency offered samples with sodium restriction and potassium load.
sample restricted sodium
Test with sodium restriction (Naggor - Weinstein - Soffer - Trescher) consists in the fact that the patient for 2-4 days include diet containing less than 0.3 grams of salt, - rice, fruit juices, vegetable juices, potatoes.Daily or every other day determine sodium, potassium, chloride, residual nitrogen and total blood protein, sodium excretion in urine, the patient's hematocrit and weight.Under normal adrenal function reserves is a significant decrease in sodium excretion in urine, and all other parameters remain within normal variation.In the presence of adrenal insufficiency urinary sodium excretion is reduced a little, and decreasing the level of sodium chloride in the blood, and the potassium content, residual blood nitrogen and total protein increased.Increased hematocrit, and the weight falls.
This test is unsafe and in patients with Addison's disease can cause adrenal insufficiency.Less dangerous modification of the sample, in which the first 3 days the patient received 7 g of sodium chloride, and the next 3 days - 2 was traced back to the same performance as that of the sample Narrog - Weinstein - Soffer - Trescher.
sample, with deprivation of salt is positive for nephrosis and nephritis with nephrotic component.
sample Cutler - Power - Wilder
modification of the sample with sodium restriction is a sample of Cutler - Power - Wilder, in which, in addition to a significant reduction of sodium in the diet made in potassium load.For this purpose, can be applied diet proposed Tsonchevym VI: 300 g of milk, 500 g of potatoes 75 g beans, beans, prunes 50 g 70 g rice 60 g of onion, 50 g of sunflower oil, 0.55 g sodium chloride.This diet contains 4.1 g of potassium, sodium 0,587-0,598 g, 0,931-0,961 g of chlorine.Further, in the 1st and 2nd days of the study allowed for potassium citrate 33-40 mg per 1 kg weight and 40 ml of water per 1 kg of body weight per day.On this diet the patient is 2 days;in the morning on the third day it is allowed to drink water at the rate of 20 ml / kg body weight, urine collected allocated between 7 and 11 a.m. and at 12 h, blood is taken for examination.
During normal function of the adrenal cortex by weight of patients, hemoglobin content and blood pressure is not changed, the level of sodium, potassium, and blood chlorides varies within the normal range, and sodium excretion, and chloride excretion is significantly reduced (the last portion of urine collected on the third day of the test,sodium below 100 mg%, chlorides below 150 mg%).In patients with adrenal insufficiency sodium and chloride excretion in urine is normal or elevated levels of sodium and chloride in the blood serum lowered potassium levels rise.Weight falls sick, the hematocrit rate increases.
This test is dangerous - can cause an acute adrenal insufficiency, and therefore should only be performed in a clinical setting.
sample may fall out positive in patients with chronic renal failure, diabetes, liver diseases, edematous states, pneumonia.
to detect adrenal insufficiency also used a number of samples with water load.These tests revealed deficiency of cortisol - a hormone that supports the filtration in the renal glomeruli.
Sample Robinson - Power - Keppler
Sample Robinson - Power - Keppler - within three days the patient is on a diet containing no more than 10 grams of sodium chloride.On the eve of the study with 18 hours the patient is not receiving fluid.At 22 hours, empty the bladder.At 7 am overnight urine was collected, after which drinks water - 20 ml / kg body weight.Urine is then collected at 8, 9, 10 and 11 hours. At the end of the 4th hour blood taken chlorides and urea.Under normal conditions, all the fluid is released adopted in the morning for 4 hours, and one hour of sample volume exceeds nocturnal diuresis.
27 Apr, 2016
27 Apr, 2016