Effect of different doses of ascorbic acid on thyroid activity in rats at different levels of dietary protein intake

Endokrinologie. 1975 Aug;65(3):333-9.


Rats, which can synthesize vitamin C, react similarly to graded doses of ascorbic acid as guinea pigs. Low doses of ascorbic acid stimulate and high doses inhibit the thyroid activity of rats which are supplied with normal and high percentages of protein. The stimulatory effect of low doses of ascorbic acid on hyperactive thyroid of high protein fed animals is additive. Ascorbic acid has no significant effect on the thyroid of low protein fed animals (deficient diet supplied for 21 days). In the initial stages of protein deficiency (deficient diet supplied for 11 days) the effectiveness of vitamin C on thyroid of rats was still significant. Deiodinase enzyme activity of peripheral tissues is markedly reduced in animals supplied with 2% of protein for 21 days, but this effect is less intense in animals supplied with 2% of protein for 11 days.

MeSH terms

  • Animals
  • Ascorbic Acid / administration & dosage*
  • Dietary Proteins / administration & dosage*
  • Female
  • Iodide Peroxidase / metabolism
  • Iodine Radioisotopes / metabolism
  • Organ Size
  • Rats
  • Thyroid Gland / drug effects*
  • Thyroid Gland / enzymology
  • Thyroid Gland / metabolism


  • Dietary Proteins
  • Iodine Radioisotopes
  • Iodide Peroxidase
  • Ascorbic Acid