Table 4.

Linear regression analysis for plasma citrulline versus CCN per day over IR doses of 6–15 Gy. Day 6 covered IR doses of 6–13 Gy. The day corresponded to the number of days post the IR event. The estimate referred to the estimated increase in CCN value per one unit (1 μM) increase in plasma citrulline. The p-value of <0.05 (two-sided test) was considered significant. The R² value was generated via linear regression analysis.

Plasma Citrulline versus Corrected Crypt Number
Day Post-IR	Estimate (CCN)	p-value	R2
Day 1	0.15	0.3675	0.017
Day 2	3.85	<0.0001	0.600
Day 3	3.02	<0.0001	0.696
Day 4	1.81	<0.0001	0.871
Day 5	1.62	<0.0001	0.901
Day 6	1.61	<0.0001	0.640