TABLE 3.

Tumor sizes in ^Pirc/+ rats fed diets supplemented with 25(OH)D₃ or vitamin D₃¹

Dietary compound and dose2	Total colonic tumors followed, n	Size	P-value
Tumor areas obtained from measurements by using a microscope reticule
25(OH)D3 [μg/(kg body weight · d)]
Males
0	97	13 ± 15 mm2	—
60	90	15 ± 14 mm2	0.06
170	146	15 ± 14 mm2	0.07
500	108	12 ± 14 mm2	0.77
1500	99	9 ± 7 mm2	0.61
4500	117	9 ± 8 mm2	0.29
Females
0	70	11 ± 11 mm2	—
60	39	10 ± 14 mm2	0.72
170	38	11 ± 9 mm2	0.31
500	31	11 ± 8 mm2	0.24
1500	99	9 ± 7 mm2	0.87
3000	65	9 ± 9 mm2	0.64
4500	148	8 ± 6 mm2	0.95
Tumor volumes obtained by using the alginate molding method
Vitamin D3 [μg/(kg body weight · d)]
Females
0	10	20 ± 36 mm3	—
6	5	6 ± 5 mm3	0.40
60	42	7 ± 7 mm3	0.50
500	56	12 ± 17 mm3	0.89
1500	77	13 ± 16 mm3	0.69

¹Values are means ± SDs unless otherwise indicated. Although a trend for decreased tumor area with increasing 25(OH)D₃ dose was apparent, no individual dose differed significantly from vehicle controls. Low-dose vitamin D₃ supplementation appeared to decrease average tumor volume compared with controls; however, this was not significant. 25(OH)D₃, 25-hydroxycholecalciferol.

²Dose = the supplementation of base diet, which contains 1 IU vitamin D₃/g diet.