Endocrine factors contributing to the ethanol preferences of rodents.

Groups of C57 Bl/6j mice (alcohol preferring) and DBA/2j mice (alcohol avoiding) were fasted for 24 hours and administered glucose. At 30, 120 and 300 minutes after glucose, the C57 Bl/6j mice had significantly higher levels of plasma glucose than the DBA/2j strain. These differences were observed in comparable groups given either forced access or no access to alcohol. In ad lib fed animals never exposed to alcohol, C57 Bl/6j mice had higher levels of plasma insulin than DBA/2j mice. Plasma levels of glucose and corticosterone were not significantly different in ad lib or fasted animals. The injection of insulin zinc protamine to DBA/2j mice produced 100% convulsions within one hour, but produced to convulsions in C57 Bl/6j mice for as long as 4 hours after administration. These data demonstrate that an insulin resistancy exists in C57 Bl/6j mice which is not dependent upon any prior alcohol experience. Evidence supporting a functional relationship between this diabetogenic disturbance and alcohol preference was obtained in C57 Bl/6j mice which were allowed to choose between water or a 10% alcohol solution (v/v). Insulin zinc protamine produced a selective dose-dependent reduction in alcohol intake. Additional support is received from the discovery that Chinese hamsters, a species genetically predisposed to diabetes, display an impressive preference for 10% alcohol.