Changes of plasma 11-hydroxycorticosteroids and catecholamines levels during noradrenalinaemia and adrenalinaemia in non-anaesthetized sheep.

In experiments on non-anaesthetized sheep it was found that after noradrenaline (NA) administration the plasma level of 11-hydroxycorticosteroids (11-OHCS) increased, similarly as the level of endogenous adrenaline (A). During noradrenalinaemia the rise in the plasma concentration of these hormones depended on the dose of NA. It was demonstrated that the released 11-OHCS retained the injected NA in the circulation. Similar changes occurred during adrenalinaemia. In the paper the connection is discussed between inhibition of the extraneuronal uptake of plasma catecholamines and their exchange for the stored endoneural catecholamines.