In the present study, effects of $eta$-alanine, a known taurine antagonist for its structural similarity, on the adaptive regulation and kinetic behavior of the taurine transporter were investigated in the HT-29, human colon carcinoma cell line. Pretreatment of the cell with $eta$-alanine(10mM) for varying periods from 3 to 30 hrs significantly reduced the taurine uptake compared to the value for control cells. This decrease in the taurine transporter activity was dependent on the incubation time with $eta$-alanine, and the maximal down-regulation of the transporter activity was observed in cells pretreated with $eta$-alanine for 24 hrs (25% of the control value, p<0.01). The taurine transporter appears to bind exclusively with $eta$-alanine in the HT-29 cells since the same concentration of $alpha$-alanine added in the culture medium for 24 hrs did not influence the taurine uptake. Kinetic analyses of the taurine transporter activity was performed in the HT-29 cell line with varying taurine concentration (5~60$mu$M) in the uptake medium. Active taurine uptake was significantly lower in $eta$-alanine pretreated cells compared to the value for control cells in the range of taurine concentration used in the experiment (p<0.001). The cells pretreated with $eta$-alanine showed a 50% lower maximal velocity (Vmax, 1.7$pm$2.0 nmole.mg $protein^{-1}$.$30min^{-1}$), and a 99% higher Michaelis constant (Km, 40.3$pm$7.6$mu$M) than the control values (3.3$pm$1.9 nmole.mg $protein^{-1}$.$30min^{-1}$, and 20.3$pm$2.1$mu$M, respectively). These results on kinetic data suggest that $eta$-alanine induced down-regulation of the taurine transporter activity was associated with decreases in both maximal velocity and affinity of the transporter.