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Sex Differences in Mouse Hippocampal Astrocytes after In-Vitro Ischemia
Published on: October 25, 2016
Sex differences in hypothalamic astrocyte response to estradiol stimulation
John Kuo1, Naheed Hamid, Galyna Bondar
1Department of Neurobiology, Laboratory of Neuroendocrinology of the Brain Research Institute, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA. pmicevych@mednet.ucla.edu.
Biology of Sex Differences
|January 7, 2011
Summary
Hypothalamic astrocytes show sexual differentiation. Estradiol stimulates progesterone synthesis in female astrocytes, but not males, indicating ovarian influence on reproductive function.
Area of Science:
- Neuroendocrinology
- Cellular Biology
- Reproductive Science
Background:
- Hypothalamic reproductive functions are sexually differentiated, notably estrogen positive feedback triggering ovulation.
- Estradiol facilitates progesterone synthesis in female hypothalamic astrocytes, unlike in males, impacting luteinizing hormone (LH) surge.
- Investigating sexual differentiation in hypothalamic astrocytes' cellular responses to estradiol is crucial.
Purpose of the Study:
- To determine if hypothalamic astrocytes exhibit sexual differentiation.
- To analyze the cellular responses of female and male astrocytes to estradiol stimulation.
- To elucidate the role of sex steroids in astrocyte function.
Main Methods:
- Primary adult hypothalamic astrocyte cultures from wild type, ERKO, and FCG mice.
- Analysis of Sry expression via RT-PCR.
- Measurement of intracellular calcium ([Ca2+]i) and progesterone synthesis.
- Assessment of membrane estrogen receptor-alpha (mERα) levels.
Main Results:
- Estradiol stimulated [Ca2+]i release and progesterone synthesis in female astrocytes; male astrocytes showed altered [Ca2+]i but no enhanced progesterone.
- Surface biotinylation confirmed mERα in both sexes, but estradiol increased membrane insertion only in females.
- Estradiol-induced progesterone synthesis was dependent on the presence of ovaries, irrespective of chromosomal sex.
Conclusions:
- Hypothalamic astrocytes are sexually differentiated, reflecting developmental sex steroid actions.
- Ovarian presence, not chromosomal sex, dictates hypothalamic astrocyte response to estradiol.
- Differential mERα trafficking in female astrocytes suggests sexually differentiated cell signaling.
