Endocrine Abstracts

Low birth weight has been reported in the offspring of rats fed with low salt diet. This study estimated the levels of maternal growth factors of pregnant rats fed with low salt and high salt diet. Seventy-two female Sprague–Dawley rats were acclimatized and divided into three groups consisting of control/normal salt diet (0.3% salt), low salt diet (0.14% salt) and high salt diet (8% salt). Rats were fed for six weeks and the cycles of the rats were observed in the 6th week for the introduction of male rats to female rats on the evening of proestrus for mating. The presence of sperm cells in the smears the following day confirmed mating and was taken as day one of pregnancy. Implantation studies were carried out on days 6 and 8 of pregnancy while fetal parameters were ascertained on day 19 of pregnancy and at term. Transforming growth factor β-1 (TGFβ-1) and Insulin like growth factor -1 (IGF-1) levels were measured on days 6, 8 and 19 of pregnancy. The results showed that implantation sites were decreased on days 6 and 8 in high salt fed rats. Litter size was decreased in both low and high salt diet fed rats, while birth weight was decreased in low salt fed rats and placental to birth weight ratio was increased in the high salt fed rats compared with control. There was a significant decrease in IGF-1 levels on days 8 and 19 of pregnancy in low salt fed rats while TGFβ-1 levels were decreased on days 6, 8 and 19 of pregnancy in low salt fed rats. Findings suggest that reduced fetal development and low birth weight in low salt fed rats is associated with reduced levels of IGF-1 and TGFβ-1 during pregnancy.