Cyclic Nucleotides and the Activity of Glia Maturation Factor in the Hypoplastic Cerebellum of Developing Jaundiced Gunn Rats

Developmental changes of cyclic nucleotides were studied in the hypoplastic cerebellum of jaundiced Gunn rats over the period of postnatal days 8 to 30. The mitogenic activity of glia maturation factor was also measured at day 15. In jaundiced homozygotes (jj), the amount of cyclic GMP on a protein basis was not significantly different from that in control heterozygotes (j+) at either day 8 or 15, but at day 30 it was reduced to about 19% of the control. On the other hand, a lowered nucleotide level on a wet weight basis in jj rats was already statistically significant at day 15. In contrast to cyclic GMP, the rates of increase of cyclic AMP on a wet weight basis were almost the same in the two groups of rats, but the nucleotide levels on a protein basis at days 15 and 30 were a little, but significantly, higher in jj rats than in j+ rats. The activity of glia maturation factor in jj rats was found to be 1.5-3 times as high as that in j+ rats. Possible implications of the present results are discussed.