Dexamethasone Concentrations in Ovine Plasma During its Intravenous Infusion, its Relation to the Production of Some Endogenous Hormones, and Some of the Effects on Wool Growth

Abstract

Plasma concentrations of dexamethasone have been measured in sheep during an 8-day infusion of dexamethasone-21-phosphate. The dexamethasone concentration profiles generally revealed a reproducible pattern with three phases-a peak during the first 48 h infusion which was followed by falling concentrations during the next 5 days, and a small increase in dexamethasone concentration during the final 24 h infusion was not uncommon. The pattern of dexamethasone concentrations was retained when dosage was arranged in such a way as to infuse increasing quantities of hormonal analogue as infusion progressed. Aspects of the metabolism of the analogue are discussed.