Leptin Causes the Early Inhibition of Glycolysis- and TCA Cycle-Related Genes in the Brain of Ob/Ob Mice to Restore Fertility

Abstract

Introduction: Polycystic ovarian syndrome (PCOS) is undoubtedly the commonest androgen disorder in woman’s fertile period and certainly one of the most prevalent causes of anovulation. The syndrome has an estimated prevalence of 4% - 10% among women of childbearing age. Previously, our group demonstrated the effect of gonadal white adipose tissue transplantation from wild-type lean and fertile female mice to isogenic obese anovulatory ob/ob mice. These complex metabolic interrelationships between obesity and PCOS have yet to be fully understood. The aim of this study was to evaluate the effect of gonadal white adipose tissue (WAT) transplantation from the wild-type lean and fertile female mice to isogenic obese, anovulatory mice (Lep ob/Lep ob) on the expression of glycolysis- and TCA cycle-related genes and obtain a general view of the glucose metabolism in the brain of these animals. Methods: Fifteen ob/ob mice ranging from 2 to 3 months of age were divided into 3 experimental groups: control normal weight (n = 5), obese control (n = 5) and obese 7 days leptin treated (n = 5). The whole brains of the mice were processed for RNA extraction. The samples from each group were used to perform PCR assays using an array plate containing 84 primers to study the glucose metabolism-related genes. Results: The glycolysis- and TCA cycle-related genes were significantly downregulated. The most significantly affected genes were as follows: for glycolysis (fold regulation with p < 0.05):Pgm1,Bpgm,Aldob, andEno3 (119, 45, 18, and 28 times less, respectively); and for the TCA cycle (fold regulation with p < 0.05):Cs,Idh3b, andMdh2 (84, 27, and 37 times less, respectively).Conclusion: The seven-day leptin treated mice show a decrease in the glucose metabolism. These results confirm the ability of the adipose tissue-derived hormone leptin to regulate early crucial genes that are related to glycolysis mechanisms and to the TCA cycle. This hormone seems to revert early the central physiological conditions that are associated with PCOS; however, the morphological alterations can only be observed within a 45-day treatment.