Submitted to: Hormone Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: April 30, 1998
Publication Date: N/A
Interpretive Summary: A study was conducted to determine the variation within and between subjects on urinary excretion of three catecholamines, namely epinephrine (EPI), norepinephrine (NE) and dopamine (DA). These three hormones are directly involved in the regulation of body weight gain and are synthesized and secreted by the sympathoadrenal system. Therefore, by measuring their concentration levels in the urine, one is able to evaluate the activity of the sympathoadrenal system. Twenty-two women and twelve men collected 24- hour urine samples during two periods of 4 consecutive days. They were fed controlled diets (either a low or a control fat diet) throughout the study and consumed a beverage that was supplemented with alcohol during one of the 2 study periods. Results demonstrated that men excreted more EPI and NE in the urine than women. In addition, a moderate consumption of alcohol for 8 weeks did not affect excretion of all three catecholamines. Both within- and between-subject variation was smaller during alcohol consumption in al subjects. Furhermore, within subject variation was the same for men and women and between-subject variation was always greater for women than men during alcohol consumption and abstention. The information gathered from this study is important to the scientific community for some major reasons: first, there is no information currently available in the literature on the variation in urinary excretion of catecholamines in humans; secondly, this information will be used by investigators to predict the number of subjects needed to detect significant differences in urinary catecholamine excretion in response to dietary manipulation.
Technical Abstract: Twenty-two women and 12 men collected 24-hour urine samples under free- living conditions. Subjects were fed controlled diets (20% or 40% of energy from fat) for two 8-week periods; within each dietary group, subjects consumed a carrier beverage with ethanol (5% of daily energy intake) during one 8-week period. Urine samples were collected during week 5 of each period for 4 consecutive days and analyzed for epinephrine (EPI), norepinephrine (NE), and dopamine (DA) by HPLC with electrochemical detection. Coefficients of variation were determined separately for men and women and for alcohol consumption within sex. Daily excretion of EPI and NE was significantly greater (p<0.01) in men than in women. Alcohol consumption did not significantly affect the levels of urinary catecholamine excretion within sex. However, both within- and between- subject variation decreased during alcohol consumption in all subjects. Within-subject variation was similar for men and women and between-subject variation was consistently greater for women than men during alcohol consumption and abstention.