Does thyroid hormone influence the maturation of cerebellar granule neurones?
The following hypotheses were tested: is the degeneration of differentiating granule cells in the internal granular layer of the thyroid deficient cerebellum due to a direct requirement of these cells for thyroid hormone, or is it mediated through the failure of some of these cells to make synaptic contact with the hypoplastic Purkinje cells? The effect of thyroid hormone (T3) was studied in rat cerebellar cultures which contain predominantly granule cells. The cultures were grown in a chemically defined medium (S-) in the presence or absence of T3, and were also compared with serum (and thus thyroid hormone) containing cultures (S+). It would appear that T3 is not essential for the relatively long-term survival of the granule cells. Furthermore, cell growth in terms of protein accretion, and the morphological appearance of the cultures were also similar in S- in the presence and absence of T3. Maturation of granule cells was followed by estimating indices, which in the cerebellum in v
