Fetal lung development in streptozotocin-induced experimental diabetes: cytidylyl transferase activity, disaturated phosphatidyl choline and glycogen levels

Gestational diabetes affects postnatal development of transport and enzyme functions in rat intestine

The effect of alloxan-induced gestational diabetes on the postnatal development of brush border disaccharidases and D-glucose transport in rat intestine was studied. Pups born to diabetic mothers showed 92-22% increase in blood sugar levels compared with the controls. Western blot and RT-PCR analyses revealed that the activities of brush border sucrase, lactase and Sodium Glucose Co-transporter 1 (SGLT1) correlates with protein and mRNA levels in intestine of pups born to diabetic rat mothers after 5-45 days of birth. Intestinal histology in pups born to diabetic mothers at day 10 and 45 after birth showed distorted cellular organization of mucosa with a decrease in the number of secretary goblet cells and regression of tubular mass. These findings suggest that the genetic switch in utero regulates the postnatal expression of enzyme and transport functions in intestine of pups born to diabetic rat mothers. This may influence the growth and development of offsprings later in life.

Delayed pulmonary maturation in the fetus of the streptozotocin-diabetic rat

Pulmonary maturation was studied in fetuses in streptozotocin-diabetic rats on the final four days of gestation. Diabetes was induced prior to conception by the intravenous injection of streptozotocin. Fetuses were hyperglycemic but did not manifest hyperinsulinemia. Whole lung total phospholipid, phosphatidylcholine, and disaturated phosphatidylcholine were significantly decreased in the diabetic group on day 21 (term = 22 days), but not prior to or after that point in gestation. Morphologic analysis also revealed a decreased number of type II cells and lamellar bodies per alveolar lining cell in the diabetic group only on day 21, coincident with the changes in phospholipid analysis. Activities of enzymes involved in fetal pulmonary phospholipid synthesis were measured to see if differences could account for the observed developmental delay. No significant differences between diabetic and control lungs were noted in any of the enzymes studied from days 20-22, with the exception of an increase in cholinephosphate cytidylyltransferase activity in the diabetic fetuses on day 22. Immaturity in both biochemical and morphologic indices of lung development was present at a specific time late in the diabetic rat gestation. This maturational delay could not be accounted for by changes in the activities of enzymes involved in phospholipid synthesis. The fetus of the streptozotocin-diabetic rat provides a useful model to study the effects of hyperglycemia on fetal lung development.

Decreased utilization of [2-3H]glycerol in phospholipid and neutral glyceride biosynthesis in the retina of streptozotocin-diabetic rats

The effect of streptozotocin (STZ)-induced diabetes on lipid uptake was studied in the rat retina. The intravitreal incorporation of [2-3H]glycerol was followed in retinal lipids from the first day of diabetes (acute state) up to 20 wk (chronic state). Total lipid incorporation decreased 50% 2 d after injection of STZ; the labeling remained lower than the control values throughout the 20 wk period studied. In the chronic state of diabetes, the time-course of the incorporation of [2-3H]glycerol during the first 2 h after its injection displayed a pattern of incorporation similar to that of the controls. The possibility that the decreased utilization of [2-3H]glycerol in the lipid pathway results from a competition between the injected [3H]glycerol and the glycolytic pathway during diabetes in rat retina in vivo is discussed.