Metabolic actions of cortisol in a macropodid marsupial Thylogale billardierii

In undisturbed pademelon wallabies (Thylogale billardierii) with indwelling jugular venous catheters, an increase in the plasma cortisol concentration from 0.25\m=+-\0.05 to 1.35\m=+-\0.15(S.E.M.) \g=m\mol/1in 2 h, during i.v. infusion of cortisol at 1.0 mg/kg per h, caused no significant change in the plasma glucose concentration from the control value of 4.26\m=+-\0.25mmol/1. The rates of appearance (Ra) and metabolic clearance(MCR) of glucose, measured by steady-state isotope dilution, also did not change significantly from the control values of 14.9\m=+-\0.7 \g=m\mol/kgper min and 3.52\m=+-\0.19 ml/kg per min respectively. Twice-daily i.m. injections of 7 mg cortisol/kg for 7 days caused increases in plasma concentrations of cortisol, from 0.26\m=+-\0.02 to 0.66\m=+-\0.04 \g=m\mol/1on day 7, and glu