Action of Steroid Hormones on Growth and Differentiation of CNS and Spinal Cord Organotypic Cultures

Cellular and Molecular Neurobiology, 1996 · DOI: · Published: January 1, 1996

Simple Explanation

This study investigates how steroid hormones influence the development of the nervous system using in vitro methods. Specifically, it looks at the effects of estrogen and testosterone on neuronal sprouting and myelination in organotypic cultures of the hypothalamus and spinal cord from rat fetuses. The researchers exposed these cultures to estrogen (17β estradiol) and testosterone and observed the resulting changes. They found that estrogen enhanced the sprouting of hypothalamic neuronal fibers and increased the amount of synapses. In spinal cord cultures, testosterone induced the regeneration of thick nerve processes and an early onset of myelination. These findings suggest that steroid hormones play a significant role in the development and differentiation of the central nervous system.

Study Duration

17 days

Participants

Sprague-Dauley rat fetuses (E16 and E14)

Evidence Level

In vitro study

Key Findings

1
Estrogen (17β estradiol) enhances sprouting of hypothalamic neuronal fibers.
2
Estrogen increases the number of synapses in hypothalamic cultures.
3
Testosterone induces regeneration of thick nerve processes in spinal cord cultures.

Research Summary

During the prenatal period, gonadal steriod environment induces dramatic sexually dimorphic changes in the nervous system. We have used in vitro methods to study the mechanism and timing of hormonal influences on neuronal sprouting and myelination during the prenatal period. Both steriod hormones were active: 17/3 estradiol enhanced sprouting of hypothalamic neuronal fibers and increased the amount of synapses. In SC cultures T induced regeneration of thick nerve processes and an early onset of myelination, mainly of peripheral myelin.

Practical Implications

Sexual Differentiation

The findings suggest that estrogen-induced neurite extension in hypothalamic slices may play a role in sexual differentiation of the brain.

Spinal Cord Innervation

The study suggests that testosterone-induced long myelinated fibers in the male spinal cord might be connected with the sexual dimorphic innervation of the bulbocavarnosus muscle.

Therapeutic Potential

Understanding the role of steroid hormones in neuronal development and myelination could provide insights into potential therapeutic interventions for neurological disorders.

Study Limitations

1
In vitro study may not fully replicate in vivo conditions.
2
Specific mechanisms of hormone action require further investigation.
3
The study focuses on rat fetuses; results may not be directly applicable to other species.

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