GENDER-DEPENDENT REDUCTION OF SPONTANEOUS MOTOR-ACTIVITY AND GROWTH IN RATS SUBJECTED TO PORTACAVAL-SHUNT

Alterations in behavior are frequently described in rats subjected to portacaval shunt. Previous work has reported reduced spontaneous motor activity in various settings (nighttime, red light, decreased illumin ation) in this animal model. We investigated this phenomenon in rats o f both genders subjected to portacaval shunt to determine whether our previously observed divergent growth patterns (males reduced, females unchanged) had any impact on the alterations in spontaneous motor acti vity in this model. Dietary intake, growth, motor activity and serum a mmonia and amino acid concentrations were measured, is addition to fin al liver and spleen weights, in each animal after 3 to 4 wk of observa tion. Our results reconfirm the differential impact of portacaval shun t on growth in male (35% reduction p < 0.01) but not female rats (5% r eduction, NS) compared with their respective-gender sham-operated cont rols. In addition, spontaneous motor activity was significantly reduce d in male (similar or equal to 50%, p = 0.01) but not female rats subj ected to portacaval shunt. The reduction of activity in male rats subj ected to portacaval shunt did not correlate with any of the measured b iochemical data or calculated nutritional/growth parameters. Thus we o bserved gender-dependent reduction in spontaneous motor activity after portacaval shunt in the rat. The mechanism for this phenomenon is unk nown, but it is easily investigated with this reproducible model.