Table 1.

Factors influencing changes in short-circuit current (I_sc) across epithelia of small intestines in Ussing chambers after substrate addition

	Substrate
	10 mM Glucose					12 mM Glycyl-l-Glutamine
Fixed Effects	Coefficient	Standard Error	F	df	P	Coefficient	Standard Error	F	df	P
Log (Isc before substrate addition)	0.95	0.042	519.55	1,19	<0.001	1.13	0.076	224.72	1,21	<0.001
Seasona	0.11	0.029	15.35	1,19	<0.001	0.09	0.043	4.66	1,21	0.043
Log (age in months)	0.05	0.020	6.09	1,19	0.023	0.01	0.029	0.22	1,21	0.647
Reproductionb	0.06	0.047	1.88	1,19	0.186	0.05	0.079	0.37	1,21	0.547
Gut sectionc	0.01	0.063	0.04	1,19	0.850	0.10	0.052	4.06	1,21	0.057
Type of killingd	0.02	0.037	0.44	1,19	0.516	0.05	0.056	0.82	1,21	0.374

Statistics are obtained from linear mixed modeling with log-transformed-dependent variable, and “animal” as random factor to correct for repeated measurements in two gut sections of each individual.

^aJanuary or February vs. July.

^bGravid (winter) or lactating (summer) vs. not reproducing.

^cMid-jejunum vs. distal jejunum.

^dGun shot vs. pin shot.