Table 1.

Transport of ²²Na⁺ and [¹⁴C]isoleucine in oocytes expressing 4F2hc and LAT1

Injected cRNA	[14C]Ile uptake(pmol (10 min)−1)	22Na+ uptake(nmol (5 min)−1)	Icat(nA)
4F2hc	1.3 ± 0.2	0.33 ± 0.01	7.8 ± 4.1
4F2hc/LAT1	36 ± 4	1.68 ± 0.4	215.3 ± 9.6
4F2hc/LAT1/sgk-1	38 ± 2	4.44 ± 0.7	750.1 ± 193.6

Oocytes were injected with 5 ng of 4F2hc cRNA, 5 ng of 4F2hc and 5 ng LAT1 cRNA, or 5 ng 4F2hc and 5 ng LAT1 cRNA plus 3 ng human sgk-1 cRNA, followed by an expression period of 1 day. [¹⁴C]isoleucine uptake was determined using an incubation time of 10 min; ²²Na⁺ uptake was followed over 5 min. Flux studies were performed in ND96 buffer containing 96 mM NaCl. I_cat was determined as the difference between the current in the absence and presence of monovalent cations. The mean uptake activity of seven oocytes was determined for each measurement, one of four experiments shown.