Rudas Lab - Clinical Laboratory - Χημείο Ρούδα

Sample: 24 hrs urine sample in 6N HCl: In a big plastic container add 5 mL distilled water and then add 5 mL concentrated (about 38%) HCl, close the container and give to the patient (warning: this preservative is an strong acid!. If it becames in contact with the skin, wash with plenty tap water) The first urine sample is not collected and the last sample (after exactly 24 hrs) is collected. The container is kept in a fresh place, avoiding direct sunlight. Send 20 mL of sample to the Lab.

Schedule: One week (HPLC ECD)

Units: nmol/ 24 hrs

Range: Up to 150 nmol/24 hrs

Remarks: Noradrenaline and adrenaline have a similar action, with adrenaline being the more potent. Both work on the peripheral sympathetic nervous system: heart, blood vessels, gut, adipose tissue, lungs, bladder and genitalia. They are secreted by the adrenal medulla and cause: vasoconstriction, dry mouth, pupil dilation, increased heart rate, sweating and increased glycolysis.

Noradrenaline also has some mood/depression function. Serotonin (5-HT, 5-hydroxytryptamine) is released at tissue injury and causes inflammation, increased capillary permeability, increased pain response, increased appetite. It is also a brain neurotransmitter which increases mood. It is produced at higher levels in summer months and levels are effectively increased by antidepressants such as fluoxitine.

In a high blood pressure crisis, the body requires an extra boost of blood, which carries oxygen and important nutrients that better equip the body to cope with stress. At such times, the body may release adrenaline, a hormone that helps regulate blood pressure. Adrenaline works in two ways: It signals the heart to beat more rapidly and forcefully. It signals the arteries to narrow and to lose some of their flexibility.

Each of these actions alone would raise the blood pressure. Together, they even more dramatically boost blood flow to the brain and other body parts so that the person is better able to handle stress.

Catecholamines are the hormones of the adrenal medulla: Dopamine, Norepinephrine (Noradrenaline) and Epinephrine (Adrenaline) whereas Metanephrines are their metabolites: 3-Methoxytyramine, Normetanephrine (Normetadrenaline) and Metanephrine (Metadrenaline), respectively. The final products of the metabolism of both Catecholamines and Metanephrines are Homovanillic acid (HVA) and Vanillylmandelic acid (VMA). Dopamine and Catecholamines are produced in elevated concentrations by the tumour cells of patients with pheochromocytoma. These patients often show hypertension, anxiety, pallor and trembling.

Dopamine and Catecholamines and also produced by neuroblastoma cells but usually not in concentrations enough to produce symptoms. The urinary concentrations of Catecholamines and Metanephrines are important in the differential diagnosis of hypertension, for the evaluation of congestive cardiac insufficiency, coronary heart disease, diabetes mellitus, arteriosclerosis, acute asthma and others.

In order to evaluate patients with autonomic stimulation (hypertension, anxiety, pallor, trembling, etc) or with pheochomocytoma the best clinical strategy is the HPLC-ECD measurement of urinary Catecholamines (hormones), Metanephrines (their metabolites) and HVA and VMA (the final metabolism products)