Journal of Neuroscience, Vol 11, 2614-2621, Copyright © 1991 by Society for Neuroscience
Genetic hypothyroid mice: normal cerebellar morphology but altered glycerol-3-phosphate dehydrogenase in Bergmann glia
T Sugisaki, T Noguchi, WG Beamer and LP Kozak
Department of Physiology, Toho University School of Medicine, Tokyo, Japan.
The present study was undertaken to investigate the effects of thyroid
deficiency on cerebellar development with mouse endocrine genetic models.
Four types of mutant mice, the growth hormone- and thyroid
hormone-deficient Snell dwarf mouse (dw/dw), the growth hormone- deficient
little mouse (lit/lit), the primary hypothyroid mouse (hyt/hyt), and the
congenital genital goiter mouse (cog/cog) were analyzed for expression of
the glial enzyme marker glycerol-3-phosphate dehydrogenase (GPDH) and
several other marker proteins. GPDH expression, as determined by enzyme
activity and Northern blot analysis, was reduced by about 50% in the
cerebellum and brainstem of the three hypothyroid mutant mice. No reduced
expression was found in any region of the brain of the growth
hormone-deficient lit/lit mutant. Visualization of GPDH by immunohistology
showed that the immunoreactive enzyme was strikingly reduced in the
Bergmann glial cells of dw/dw, hyt/hyt, and cog/cog mutant mice,
particularly in the radial glial processes. To evaluate the specificity of
the effect on GPDH expression, we also examined the expression of the glial
cell-specific S-100 protein by immunohistology. In all mutant cerebella,
both the intensity and pattern of staining of the Bergmann glial cells were
indistinguishable from that of normal controls, suggesting that the
Bergmann glial cells are morphologically normal in the hypothyroid mice.
The morphology of the Purkinje cell neurons was similarly visualized by
immunohistology using an antiserum specific for the microtubule-associated
proteins. Surprisingly, the morphology of the Purkinje cell dendritic
arborization also appeared unaltered in the hypothyroid mice. The results
suggest that the morphological development of the mouse cerebellum is
relatively unaffected by hypothyroidism.(ABSTRACT TRUNCATED AT 250 WORDS)