Birth Weight and Fetal Mortality in Pregnant Subdiabetic Rats

Abstract

It has been reported that diabetic women frequently give histories of fetal overweight and of increased fetal mortality in pregnancies occurring many years before the development of manifest diabetes. 1 Wilkerson studied the glucose tolerance in a large series of pregnant women. 2 In those instances where he observed abnormal carbohydrate tolerance during pregnancy, he found that newborns weighing nine pounds or more occurred three times as frequently as in the group with normal carbohydrate tolerance.Lazarow reported that subdiabetes in rats could be produced by injecting subthreshold doses of alloxan. 8 Although these rats had an abnormal tolerance to glucose, their fasting and postprandial blood sugars were normal. They did not show any glycosuria.In two thirds of these animals, subdiabetes persisted for a period up to a year and more. One third of these animals developed manifest diabetes (hyperglycemia and glycosuria) during the first year.The present study was undertaken to determine whether pregnant subdiabetic rats likewise show a high incidence of stillborns and overweight newborns. METHODSThe animals used were albino rats of a subline of the Sprague-Dawley strain (Holtzman). Most of the rats were virgin females, 120 to 150 days in age, weighing between 230 and 280 gm. The rats were fed a standard diet of Purina fox chow. Food and water were supplied ad libitum. The experimental and control animals were maintained under similar conditions. Production of subdiabetes: Alloxan was dissolved in distilled water to make a 2 or 4 per cent solution immediately prior to injection. Nonpregnant females were injected intravenously with alloxan in a dose of 25 or 30 mg. per kg. of body weight (Lazarow and Palay). 4 A few rats were injected with alloxan on the twelfth day of pregnancy. Those rats which did not show either ĥ yperglycemia or glycosuria were subjected to glucose tolerance tests. Animals were fasted sixteen to eighteen hours and injected intravenously with a 30 per cent glucose solution in a dose of 3 gm. per kg. of body weight. Blood sugars (BS) were determined by the Folin-Malmros micromethod. 5 The diabetic index (I D ) which is a measure of the degree of abnormality of glucose tolerance was determined for each test, using the following formula (Coupland, Davidson and Lazarow). 6 _ t hr. experimental BS 2 hr. experimental BS 1 hr. average normal BS 2 hr. average normal BS In forty-two tolerance tests carried out in twelve normal rats, the average one-and two-hour blood sugar values were 175.2 and 111.9 mg. per cent, respectively, and those values were used in calculating the diabetic index. The index determined in normal rats equals 1.00 plus or minus the standard deviation of 0.30 (Coupland, Davidson, and Lazarow). 7 All fourteen subdiabetic rats had diabetic indices greater than 2.0, i.e., more than three standard deviations greater than normal. In eleven of the rats used, subdiabetes was induced prior to pregnancy; in three, subdiabetes was induced on the twelfth day of pregnancy. Since the averag...

Increased rate of lipid peroxidation and protein carbonylation in experimental diabetic pregnancy

“…Fetal weights were decreased and rates of resorptions and malformations increased in diabetic rat pregnancy; this correlates with previous studies in rodent models of diabetic pregnancy [33,34]. These negative outcomes are most likely to be caused by oxidative stress since the general morphological outcome is ameliorated by antioxidant therapy [10,12,35,36].…”

The Newborn of Diabetic Rat. I. Hormonal and Metabolic Changes in the Postnatal Period

“…The weight gain of pregnant rats was measured from day 5 to day 22 of gestation. Glycogen concentration expressed as htmole/g represents pmoles of'glucosyl residues per g wet weight of the tissue.…”

“…Similar studies in the newborn of diabetic mothers in this species are few in number and limited in intent. Studies reported so far have been concerned primarily with the effects of maternal diabetes on fetal growth (14, 15, 22,28,29) or its influence on fetal plasma and pancreatic insulin concentrations (15. 19, 21).…”

Embryopathy in Genetically Diabetic Mice, Yellow KK, and Its Prevention by Maternal Therapy

“…It is well-known that the fetuses and newborn infants of diabetic mothers are frequently abnormal. In the rat, when alloxanor streptozotocin-induced diabetic dams were used as a model for insulin dependent diabetes mellitus (IDDM), a high incidence of fetal and neonatal mortality, growth retardation, and delayed maturation of the lungs were observed (Aertz and Van Assche, 1977;Bourbon et al, 1985;Eriksson et al, 1980;Lazarow et al, 1960;Sinden and Longwell, 1949;Tyden et al, 1980). Maternal plasma insulin cannot cross the placenta, whereas plasma glucose and some kinds of lipid are freely transported between mother and fetuses (Faber and Thornburg, 1983;Goodner and Freinkel, 1961 ;Widness et al, 1983).…”