TABLE E-2 Summary of Effects of Fluoride Exposure for Rats with Different Amounts of Iodine Intake (Means ± SD)

Group

Body Weight, g

Urinary Fluoride, mg/L

Urinary Iodine, µg/24 hours

131I Uptake, % at 24 hours

Serum T4, µg/dL

Serum T3, ng/dL

TPO, G.U./100 g of body weight

[3H] Leucine Uptake, cpm/10 mg

Thyroid Weight, mg/g

  1. (control; normal iodine,a normal fluorideb)

293 ± 57

1.23 ± 0.22

1.110 ± 0.226

47.37 ± 5.66

3.64 ± 1.45

70.65 ± 30.29

2.04 ± 0.22

1,808 ± 358

9.97 ± 3.52

  1. (normal iodine,a fluoride, 10 mg/L in drinking water)

294 ± 85

6.65 ± 0.91c

1.215 ± 0.357

44.74 ± 5.14

3.02 ± 1.48

61.96 ± 26.02

1.98 ± 0.51

1,728 ± 790

9.58 ± 2.40

  1. (normal iodine,a fluoride, 30 mg/L in drinking water)

254 ± 68c

8.16 ± 0.89c

1.150 ± 0.87

42.73 ± 4.31c

1.44 ± 0.39c

43.00 ± 11.31c

1.73 ± 0.24c

1,258 ± 293c

7.90 ± 2.37c

  1. (low iodine,d normal fluoridef)

289 ± 72

1.23 ± 0.26

0.095 ± 0.029c

58.40 ± 9.54c,e

0.76 ± 0.70c

95.81 ± 25.18c

2.57 ± 0.44c

2,252 ± 683c

19.91 ± 11.23c

  1. (low iodine,d fluoride, 10 mg/L indrinking water)

308 ± 63

6.23 ± 0.88c

0.099 ± 0.017c

59.05 ± 7.59c,e

0.65 ± 0.57c

68.05 ± 21.96

1.75 ± 0.21c

1,804 ± 459

20.13 ± 22.10c

aNormal iodine: 310 ng/g in diet; 8.2 ng/mL in drinking water.

bFluoride: 1.856 ppm in diet; 0.4 mg/L in drinking water.

cP < 0.01, compared with group 1 (control).

dLow iodine: 20-62.5 ng/g in diet; deionized drinking water.

eAlso statistically significant at 2 hours and 6 hours (P < 0.01, compared with group 1).

fFluoride: 1.743 ppm in diet; deionized water.

ABBREVIATIONS: cpm, counts per minute; G.U., guaiacol unit; TPO, thyroid peroxidase.

SOURCE: Guan et al. 1988. Reprinted with permission; copyright 1988, Chinese Medical Association.



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