Blood content of tyrosine is an index of glucocorticoid action on metabolism.

Glucocorticoid hormones directly or indirectly control virtually all metabolic and physiological processes. Glucocorticoids are also shown to act on a multitude of genes, enzyme systems, and proinflammatory factors, but for these hormones there is no representative index of action on metabolism similar to glucose content in blood for insulin. The absence of such an index prevents the assessment of tissue provision with these hormones under various conditions and seems to be an essential cause of complications associated with the clinical use of glucocorticoid preparations. Considering specific features of tyrosine metabolism and data obtained experimentally and on a clinical model (adrenalectomy in rats and substitution therapy in endocrine disease), blood content of this amino acid seems promising as such an index. Based on comparing results of glucocorticoid treatment in patients with systemic lupus erythematosus with changes in their blood tyrosine contents, the pharmacological effect of glucocorticoid preparations is suggested to be mainly due to compensating a relative shortage of these hormones.

[Level of tyrosine in the blood of patients with acute myocardial infarction during the assessment of corticosteroid hormone production]. / Soderzhanie tirozina v krovi u bol'nykh ostrym infarktom miokarda pri otsenke obespechennosti kortikosteroidnymi gormonami.

Variations of blood 11-HOCS and tyrosine suggested as an indicator of tissue glucocorticoid provision were investigated in 54 patients with acute myocardial infarction (AMI). Where AMI takes a favourable course, the adrenocortical activity meets bodily requirements in about 25% of patients, whereas 30% show states of transitory hormonal deficit during the first 4-5 days of the disease. In severe AMI with multiple combined complications, tissue glucocorticoid deficiency was found in 73% of patients, the majority of those having high blood 11-HOCS levels. A profound disorder of the glucocorticoid control of metabolic processes is suggested.

[Experience with individual corticosteroid therapy of bronchial asthma in middle-aged and elderly patients (controlled by monitoring of blood tyrosine level)]. / Opyt individualizatsii terapii kortikosteroidami u bol'nykh bronkhial'noi astmoi pozhilogi i starcheskogo vozrasta (pod kontrolem soderzhaniia tirozina v krovi).

Blood level of tyrosine as a new clinical and laboratory indicator has been studied in bacterial asthma patients of advanced age. Tyrosine is known to affect metabolism of glucocorticoid hormones (GHs) thus reflecting GHs status of the body and permitting valid evaluation of the need in corticosteroid therapy.

[Changes in blood tyrosine levels during stress in adrenalectomized and intact rats]. / Dinamika soderzhaniia tirozina v krovi pri stressovom vozdeistvii u adrenaléktomirovannykh i intaktnykh krys.

On the 10th day after operation adrenalectomized male rats and non-operated animals of the control group were exposed to immobilization stress lasting 30 min and 4 h. The blood content of tyrosine and 11-HCS was measured before and during I day after stress. It has been demonstrated that blood tyrosine changes may be used as an index of adrenocortical reserves.

[The safety problem and a physiological strategy for using glucocorticoid hormones]. / Problema bezopasnosti i fiziologicheskaia strategiia primeneniia gliukokortikoidnykh gormonov.

Principal problems of glucocorticoid hormone application in non-endocrine diseases are discussed proceeding from the mechanism of their action and the role in organism's life. It appeared that the hazard of glucocorticoid therapy is mainly due to the absence of a test for sufficiency and real needs in these hormones. It was shown that the test has to be introduced reflecting on the whole body level the glucocorticoid activity in the cell, that is similar to blood glucose in relation to insulin. The introduction of free blood tyrosine as such test appears to allow the development of safe individual strategy for the usage of glucocorticoids.