Mabuya skinks have the most specialized allantoplacenta and the greatest degree of placentotrophy known among the Reptilia. Their recently ovulated eggs are microlecithal (1-2 mm) and lack fatty yolk platelets; thus, virtually all of the nutrients for embryonic development must pass across the placenta. We quantified the net uptake of nutrients during gestation in an Andean population of Mabuya and compared these results with other matrotrophic skinks and eutherian mammals. Total dry and wet masses, ash and organic content, ions (calcium, potassium, sodium, magnesium, iron), lipids (cholesterol, vitamin E and fatty acids in the major lipid classes-triacylglycerol, phospholipids, cholesteryl ester, free fatty acids), nitrogen (an index of protein) were measured during the different developmental stages throughout gestation, and in neonates. A significant net uptake of inorganic and organic matter was found. This uptake begins slowly during early gestation but accelerates during the last third of gestation when the growth of the embryo is maximal and the allantoplacenta has developed its greatest complexity. The drastic reduction of egg size in this clade is related to the great reduction in the contribution of lecithotrophic nutrients to the embryo, an obligatory placentotrophy from early developmental stages, and the highest placental complexity known in the Reptilia. All of these features converge with features found in eutherian mammals.

Introduction: During pregnancy, several maternal metabolic adaptations occur. One of these adaptations is the significant changes in lipid metabolism which contribute to the nutrient balance of the fetal-placental unit, essential for fetal development and lactation.Methods: In this study, serum concentration of different fatty acids in healthy pregnant women and three months postpartum were determined by capillary gas chromatography and compared to healthy non-pregnant women and men. Differences between groups were assessed with one-way analyses of variance and the post hoc Tukey-HSD test for multiple comparisons. The Mann-Whitney U test was used when a variable was not normally distributed. All statistical analyses were conducted using R statistical Software (version 3.3.1).Results: The results showed that serum levels of these maternal fatty acids increased significantly from the middle until the end of pregnancy compared to non-pregnant women and decreased at postpartum. Saturated fatty acids were observed to contribute to the highest percentage of total serum fatty acids during gestation, followed by polyunsaturated and monounsaturated fatty acids. Additionally, serum levels of total, saturated, monounsaturated, polyunsaturated and TRAN’s fatty acids were significantly elevated in healthy non-pregnant women when compared with men.Conclusion: There are significant differences in the lipid profiles among pregnant and non-pregnant women and men, with a decrease in the serum profile of all fatty acids in the postpartum period.

5'-Nucleotidase was measured in isolated fat cells from normal, hypothyroid and hyperthyroid rats. This was done to find out whether thyroid hormones had an effect on the production of adenosine by the fat cell. The results showed that 5'-nucleotidase is modified when the rats received injections of 3,3',5-triiodo-L-thyronine (T(3)). There was no change in the enzyme in hypothyroidism or when T(3) was added to incubation of cells.