Estrogen- and Satiety State-Dependent Metabolic Lateralization in the Hypothalamus of Female Rats

PLoS One. 2015 Sep 4;10(9):e0137462. doi: 10.1371/journal.pone.0137462. eCollection 2015.

Abstract

Hypothalamus is the highest center and the main crossroad of numerous homeostatic regulatory pathways including reproduction and energy metabolism. Previous reports indicate that some of these functions may be driven by the synchronized but distinct functioning of the left and right hypothalamic sides. However, the nature of interplay between the hemispheres with regard to distinct hypothalamic functions is still unclear. Here we investigated the metabolic asymmetry between the left and right hypothalamic sides of ovariectomized female rats by measuring mitochondrial respiration rates, a parameter that reflects the intensity of cell and tissue metabolism. Ovariectomized (saline injected) and ovariectomized+estrogen injected animals were fed ad libitum or fasted to determine 1) the contribution of estrogen to metabolic asymmetry of hypothalamus; and 2) whether the hypothalamic asymmetry is modulated by the satiety state. Results show that estrogen-priming significantly increased both the proportion of animals with detected hypothalamic lateralization and the degree of metabolic difference between the hypothalamic sides causing a right-sided dominance during state 3 mitochondrial respiration (St3) in ad libitum fed animals. After 24 hours of fasting, lateralization in St3 values was clearly maintained; however, instead of the observed right-sided dominance that was detected in ad libitum fed animals here appeared in form of either right- or left-sidedness. In conclusion, our results revealed estrogen- and satiety state-dependent metabolic differences between the two hypothalamic hemispheres in female rats showing that the hypothalamic hemispheres drive the reproductive and satiety state related functions in an asymmetric manner.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Electron Transport / drug effects
  • Electron Transport / physiology
  • Estradiol / pharmacology*
  • Fasting / physiology
  • Female
  • Functional Laterality / drug effects*
  • Functional Laterality / physiology
  • Hypothalamus / anatomy & histology
  • Hypothalamus / drug effects*
  • Hypothalamus / physiology
  • Mitochondria / drug effects*
  • Mitochondria / metabolism
  • Ovariectomy
  • Oxidative Phosphorylation / drug effects
  • Rats
  • Rats, Wistar
  • Satiation / physiology

Substances

  • Estradiol

Grants and funding

This work was supported by OTKA 104982 (Nemzeti Kutatási, Fejlesztési és Innovációs Hivatal; http://www.otka.hu/) to AZ, and OTKA 72186 (Nemzeti Kutatási, Fejlesztési és Innovációs Hivatal; http://www.otka.hu/) to TB (design, data collection, analysis); NKB 15930, KK UK-12021 (Faculty of Veterinary Science; http://www.univet.hu/hu/kiemelt-egysegek/tkk/palyazatok-kutato-kar-2013-16/kutato-kar/) (data collection); KK PhD-15263 (Faculty of Veterinary Science; http://www.univet.hu/hu/kiemelt-egysegek/tkk/palyazatok-kutato-kar-2013-16/kutato-kar/) (preparation of the manuscript); and 9877-3/2015/FEKUT (grant of the Hungarian Ministry of Human Resources) (preparation of manuscript).