Differentiation of fetal mouse hypothalamic cells in serum-free medium

We show here that cells dissociated from fetal mouse hypothalamus and cerebral hemispheres can be grown in primary culture in a serum-free medium (SFM). We describe several properties of these cultures and compare them to those in serum-supplemented medium (SSM). The SFM used is a modification of that described for neuroblastoma cells: neuronal survival is improved when 17 beta-estradiol is added. Initial events in culture development were similar to those observed in SSM. However, after 1 week, several differences could be noted: in SFM, the proportion of neuron-like cells was increased while the basal glial layer was noticeably reduced, and the neurite network remained less developed than in SSM. These findings demonstrate that the use of SFM permits manipulation of the types and proportions of cells in these primary cultures. This point has been already made. Several neuronal activities were studied. In cultures from both hypothalamus and cerebral hemispheres, thyroliberin (TRH)-immunoreactive cells were visualized by immunohistochemistry, and TRH was radioimmunoassayed in cell extracts and in the medium. In hypothalamic cultures, tyrosine hydroxylase was shown to remain stable for 1 week, and then declined. Glutamic acid decarboxylase disappeared very quickly in vitro, whereas choline acetyltransferase activity increased more rapidly in SFM than in SSM. It is concluded that the use of an SFM for growing normal fetal hypothalamic cells offers a promising model for studying neuroendocrine regulatory mechanisms in culture.