Nitrate induced hypothyroidism is associated with a reduced concentration of growth hormone releasing factor in hypothalamic tissue of rats

Dietary nitrate significantly inhibits the growth of male and female rats. To test the possibility that the growth hormone-releasing factor (GRF) content in hypothalamic tissue is deranged under these conditions, male and female rats were fed a diet containing 3% KNO 3 , for 6 weeks, compared to a normal diet (4×5 animals). The food intake of rats fed nitrate was reduced significantly (23 and 28% resp.). Weight gain was also decreased by 35 and 41% in male and female rats. The mean Sm-C/IGF-I concentration was 1.61 and 1.03 rU/ml in male and female control rats, whereas the concentrations in nitrate-exposed rats were 0.92 and 0.64, respectively (P<0.01)