Growth impairment caused by dietary nitrate intake regulated via hypothyroidism and decreased somatomedin.
The effect of 2 days or 6 weeks administration of the diet containing 3 per cent potassium nitrate on serum level of thyroxine (T4), triiodothyronine (T3), nitrate, methemoglobin and somatomedin activity was investigated in piglets aged 56 days. Sufficient iodine intake by mothers prevented a decrease of T4 level in piglets after 2 days administration of nitrate. However, after 6 weeks of nitrate administration a striking decrease of T4 level was found (average level less than 10 nmol l-1) which could not be prevented even by the addition of 0.5 mg iodide per kg diet. No adaptation to nitrate administration was observed. After long-term administration of nitrate a significant decrease of serum somatomedin activity was found which also showed a positive correlation with a decrease of body weight gain.
D000818:Animals; D005247:Feeding Behavior / Q000502:physiology; D006130:Growth Disorders / Q000139:chemically induced*; D007037:Hypothyroidism / Q000150:complications* / Q000188:drug therapy; D007455:Iodine / Q000627:therapeutic use; D009566:Nitrates / Q000097:blood / Q000633:toxicity*; D013002:Somatomedins / Q000097:blood / Q000172:deficiency*; D013552:Swine; D013974:Thyroxine / Q000097:blood; D014284:Triiodothyronine / Q000097:blood
D009566:Nitrates; D013002:Somatomedins; D014284:Triiodothyronine; D007455:Iodine; D013974:Thyroxine