EFFECT OF CHRONIC HYPOCORTISOLAEMIA ON PLASMA-CORTISOL CONCENTRATIONSDURING INTRAVENOUS INFUSIONS OF HYDROCORTISONE SODIUM SUCCINATE IN DOGS

Intravenous infusions of hydrocortisone sodium succinate (HSS) were gi ven at 0.625 mg kg(-1) hour(-1) and 0.312 mg kg(-1) hour(-1) to six do gs. Plasma cortisol concentrations were measured by radioimmunoassay a t 0, 15, 30, 45 and 60 minutes and then every 30 minutes for a further five hours. Chronic hypocortisolaemia was induced and maintained with mitotane and the Hss infusions were repeated after 31 and 50 days. No statistically significant difference was observed in the plasma corti sol concentrations after either period of hypocortisolaemia, but the p lasma cortisol concentrations tended to be higher in most of the dogs.