SUBCELLULAR-LOCALIZATION OF INSULIN-LIKE GROWTH FACTOR-I (IGF-I) IN PURKINJE-CELLS OF THE ADULT-RAT - AN IMMUNOCYTOCHEMICAL STUDY

Insulin-like growth factor I (IFG-I) was localized by light and electron microscopic immunocytochemistry in the adult rat cerebellum. Neurons showing the same cytological characteristics and pattern of synaptic input as Purkinje cells were IGF-I immunoreactive. In these neurons, intense electron-dense reaction product was consistently located in the rough endoplasmic reticulum and, occasionally, in multivesicular bodies and associated with the nuclear envelope. Thus, the results of this study suggest synthesis IGF-I in Purkinje cells and furthermore provide anatomical support for IGF-I participation in paracrine or autocrine regulatory systems in the brain.