A simple high-performance liquid chromatography assay for on-line determination of catecholamines in adrenal gland by direct injection on an ISRP column.

In the present research, assays were improved for the determination of catecholamines in adrenal gland. High-performance liquid chromatography with electrochemical detection was employed for quantitative analysis. The method involved direct injection of acid extract on to a serum albumin dimethylocadecyl-silane (HSA-C18) and the utilization of phosphate buffer (pH = 3.0): methanol (97:3 v/v), 0.025 g heptanosulfonic acid and 0.0025 g EDTA as mobile phase. The detection was obtained using an electrochemical detector L-ECD-6A-Shimadzu with a potential of the 85 mV. Identification was based on retention time. Quantification was performed by automatic peak-area determination. The detection limit is equal to 0.5 ng ml(-1). The HPLC method with electrochemical detection proposed here permits good separation of catecholamines in samples of adrenal gland from rats. The method has various advantages: fast, high precision and good selectivity and do not require sample treatment. The immobilization stress during 5 min did not provoke alteration in catecholamines contains in rat adrenal gland, due to the short time of the stress exposure. This study shows that the catecholamines (norepinephrine and epinephrine) adrenal increased significantly after the acute immobilization stress during 30 min as compared to control group. This increase probably is due to the emotional component of the immobilization stress. In conclusion, our studies suggest an effective participation of the adrenal glands to maintain the homeostasis of organism to the stressful conditions.

Changes in norepinephrine and epinephrine concentrations in adrenal gland of the rats submitted to acute immobilization stress.

Catecholamines act as neurotransmitters and hormones. Studies conducted to understand the synthesis and metabolism of these monoamines during stress have been the main concern of many authors. This work proposes to investigate the time course of changes in epinephrine and norepinephrine concentration in adrenal gland obtained from rats submitted to acute immobilization stress. The results of the present study indicate that acute immobilization stress during 5 and 15 min did not provoke changes in epinephrine and norepinephrine concentrations in adrenal gland in relation to the control group. Such results are justified due to the short time of the stress, showing that the stress did not provoke physiological alteration. The epinephrine and norepinephrine concentrations in adrenal gland increased significantly after the immobilization session in stressed groups during 30 and 50 min as compared to control group. This increase probably is due to the emotional component of the immobilization stress. In this way, we suggested that the immobilization stress provoke increase in the biosynthesis of catecholamines in the adrenal gland from rats. However, the results shows that a maximum increase is reached at 30 min of immobilization stress and then a decrement of catecholamines levels starts at 50 min of the experimental design. This decline in catecholamines level may be consequence of adaptation to stress situations, an increase of the activity of the uptake systems and/or metabolization of catecholamines. In conclusion, these results suggest an effective participation of the adrenal glands to maintain the homeostasis of organism to the stressful conditions.