Effects of glucose on rat embryos in culture.

To elucidate the role of hyperglycaemia in causing fetal malformation, rat embryos have been grown in vitro from the head-fold stage for 48 h in the presence of excess glucose during different parts of the culture period. Culture of rat embryos for 10 or 21 h in 55 mmol/l exogenous glucose produced abnormalities observable after 48 h in culture. When embryos cultured for 10 or 21 h in excess glucose were observed by scanning electron microscopy at the end of the glucose treatment, abnormalities could be observed which may indicate how later malformations are formed. Thus it is possible that a relatively brief hyperglycaemic episode at a critical stage of embryogenesis may endanger the fetus of a diabetic mother.