Actions of steroid hormones and growth factors on glial cells of the central and peripheral nervous system

doi:10.1016/0960-0760(94)90261-5

The Journal of Steroid Biochemistry and Molecular Biology

Volume 48, Issue 1, January 1994, Pages 145-154

https://doi.org/10.1016/0960-0760(94)90261-5 Get rights and content

Abstract

Primary cultures of oligodendrocytes and astrocytes and purified cultures of Schwann cells were prepared respectively from forebrain and sciatic nerves of newborn rats. The effects of steroid hormones and growth factors on glial cell growth and on the production of myelin-specific proteins and lipids were investigated. Progesterone (P, 100 nM) decreased the proliferation of glial cells of the central nervous system. This inhibitory effect of P was abolished by the simulatenous adminnistration of the antagonist RU486, thus suggesting a receptor-mediated action of the hormone. The expression of myelin-specific proteins, including the myelin basic protein (MBP) and the 2′,3′-cyclic nucleotide-3′-phosphodiesterase (CNPase), and of a myelin-specific lipid, glactocerebroside (Gal C), was also measured during cell differentiation under different hormonal conditions. The expression of MBP in oligodendrocytes was increased by P, and this effect was not blocked by RU486. The combined application of P and insulin promoted a synergistic stimulation of MBP expression. Insulin, by itself, also increased the number of MBP-positive oligodendrocytes in culture. The effects of P and insulin appeared to be selective as dexamethasone, dehydroepiandrosterone, pregnanolone and epidermal growth factor (EGF) had no effect. Only estradiol (E₂, 500 nM) increased the number of MBP-immunoreactive cells, but in contrast to P, only a small synergism between E₂ and insulin on MBP expression was observed. The expression of CNPase, another myelin-specific protein, was also increased by P and, here again, a synergy between P and insulin could be observed. In contrast, the expression of Gal C, a myelin-specific lipid, was not modified by P or other steroid hormones. Moreover, the increase in Gal C-positive cells observed in response to insulin alone was not further potentiated by P. Glial cells of the peripheral nervous system, namely Schwann cells, are also sensitive to steroid hormones. Schwann cells contain estrogen receptors, and E₂ stimulates their proliferation in the presence of forskolin or dibutyryl cyclic AMP (dbcAMP). The mitogenic effect of E₂ was abolished by the pure antiestrogen ICI-164,384. Insulin, at micromolar concentration, also stimulated Schwann cell growth when forskolin or dbcAMP were present in the culture medium. The mitogenic effect of insulin was mediated by insulin-like growth factor I (IGF-I) receptors. Indeed, at a physiological nanomolar concentration, IGF-I but not insulin or IGF-II, increased the proliferation of Schwann cells in synergy with forskolin. In addition, Schwann cells express receptors for IGF-I.

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PaperActions of steroid hormones and growth factors on glial cells of the central and peripheral nervous system

Abstract

Recent Prog. Horm. Res.

Exp. Cell Res.

Cell

Dev. Brain Res.

J. Steroid Biochem.

Brain Res.

Recent Prog. Horm. Res.

Exp. Cell Res.

Steroid hormones: humoral signals which alter brain cell properties and functions

Recent Prog. Horm. Res.

Progesterone receptors in brain and hypophysis

Glial Cell Receptors

Demonstration of steroid hormone receptors and steroid action in primary cultures of rat glial cells

Steroid Biochem. Molec. Biol.

Neuro-steroids: biosynthesis of pregnenolone and progesterone in primary cultures of rat glial cells

Endocrinology

Physiological basis of conduction in myelinated nerve fibers

Biochemistry of myelin

Paper
Actions of steroid hormones and growth factors on glial cells of the central and peripheral nervous system