Effect of gestational alloxan diabetes and fasting on fetal lipogenesis and lipid deposition in pigs.

Experiments were conducted in pregnant pigs to determine the influence of alloxan diabetes and maternal fasting on fetal development. Maternal fasting and alloxan diabetes both increased adipose tissue thickness in fetuses at 112 days of gestation without altering body weight. Body fat was increased quantitatively only in the fetuses from the diabetic pigs (FDP). Apparently, different factors were affecting the structural development of adipose tissue and the actual storage of lipid. Fetal and maternal hepatic fatty acid synthesis were unaffected by treatments. Maternal subcutaneous adipose fatty acid synthesis were unaffected by treatments. Maternal subcutaneous adipose fatty acid synthesis was depressed by 75% in both fasted and diabetic dams while subcutaneous adipose tissue lipogenesis was increased 40-fold in the FDP. Enzymes normally associated with lipogenesis (shunt enzymes) were also affected in a similar fashion. These observations support the concept that fetal adipose de novo fatty acid synthesis is stimulated by diabetic pregnancies and is a primary mechanism by which increased lipid accumulates in the fetus.