Glucose tolerance, insulin and catecholamine levels in germfree rats

Glucose was administered intravenously to 50- and 100-day-old GF and CV rats. Fasting blood glucose levels in GF and CV rats were found to be comparable. Glucose tolerance tests showed that GF and CV rats clear glucose from the blood at a similar rate. Although insulin concentrations in 100-day-old GF rats tended to be somewhat lower than in CV rats, the percentage increase during the 30-min period after glucose administration was similar, and matched the increase in blood glucose. Levels of plasma catecholamines were analyzed fluorometrically and were found to be comparable in 100-day-old GF and CV rats. It was concluded that insulin insufficiency plays no role in the syndrome of metabolic anomalies demonstrated by the germfree rat.