C-peptide-like material in rat brain: response to fasting and glucose ingestion

Because of controversial data on the presence of insulin in the central nervous system, the presence of C-peptide immunoreactivity was followed in acid/ethanol extracts of the rat brain. C-peptide-like material was detected in whole brain extracts as well as in several brain fragments. Immunoreactive C-peptide concentrations were significantly higher in hypothalamus and olfactory bulb as compared to those in other brain regions sampled. Fasting for 72 h resulted in a decrease and oral glucose administration (0.75-1.5 g given in form of 25% water solution 30 min before sacrifice) was followed by an increase of C-peptide-like immunoreactivity in both plasma and hypothalamus.