Table 1.

Effect of barium on secretion rate, [K⁺], and K⁺ flux

Genotype	Secretion Rate, nl/min per tubule	[K+], mM	K+ flux, pmol/min per tubule	n
Effect of 2 mM barium
wBerlin
Baseline	0.29 ± 0.048	139 ± 7.8	41 ± 7.5	7
After vehicle	0.37 ± 0.057	157 ± 8.3	68 ± 16.7	7
Baseline	0.31 ± 0.060	150 ± 21.9	43 ± 9.0	8
After barium	0.01 ± 0.010	156 ± 19.1	9 ± 7.0	8
GAL4 control: w;c42-GAL4/+
Baseline	0.21 ± 0.028	117 ± 6.4	25 ± 3.6	10
After barium	0.02 ± 0.028	116 ± 11.0	4 ± 1.6	10
Irk1 knockdown: w/yw;UAS-Irk1RNAi/c42
Baseline	0.23 ± 0.028	116 ± 10.3	28 ± 4.6	9
After barium	0.05 ± 0.029	121 ± 10.2	8 ± 3.5	9
Irk2 knockdown: w;UAS-Irk2RNAi/+;c42-GAL4/+
Baseline	0.24 ± 0.024	129 ± 11.0	32 ± 4.6	11
After barium	0.03 ± 0.010	131 ± 10.8	6 ± 1.7	11
Irk1/Irk2 double knockdown: w;UAS-Irk2RNAi/+;c42-GAL4/UAS-Irk1RNAi
Baseline	0.18 ± 0.032	105 ± 10.6	20 ± 4.4	10
After barium	0.08 ± 0.022	123 ± 12.5	13 ± 4.1	10

All values shown are means ± SE. Note that K⁺ flux was calculated separately for each tubule analyzed, and therefore the value of mean secretion rate × mean [K⁺] may differ slightly from measured K⁺ flux, attributable to rounding.