The distributional and activity changes of
hypoxanthine guanine phosphoribosyltransferase (
HGPRT) were investigated in the developing mouse brain. The
HGPRT activity level was low at birth, increased rapidly during the first 7 days of life, and underwent a gradual increase thereafter to the mature level. Polyclonal antibody against
HGPRT purified from mouse brain was prepared for immunohistochemical demonstration of the
enzyme during brain development. In the cerebellum, part of the Purkinje cells was consistently immunostained throughout growth, and the presence of
HGPRT was observed in the dendrites of mature Purkinje cells. The most dominant change in
HGPRT localization was observed in the hippocampus. Little
HGPRT was detectable in the newborn mouse hippocampus. At postnatal day 7, cytoplasmic
HGPRT appeared sporadically in the granular cells independently of the region of the hippocampus. The number of positive immunoreactive cells increased with growth, and the dendrites of granular cells were also immunostained on postnatal day 28. Further immunostaining was noted in the granule cells of the dentate gyrus on postnatal day 35. The above results suggest that
HGPRT may play an important role in the developing hippocampus. Further investigations of the
HGPRT in the human hippocampus may help to clarify the mechanism underlying the
neurological disorders encountered in the
Lesch-Nyhan syndrome.