Primed continuous intraruminal infusions of tracer amounts of [2-14C]propionate were used to measure propionate production and the incorporation of propionate carbon into glucose by six sheep on a diet of 1000 g chopped hay/day. Primed continuous intravenous infusions of [U-14C]glucose were used to measure the rate of glucose entry in the same sheep. The measurements were repeated 24 h after a single intramuscular injection of betamethasone. Maximum hyperglycaemia and a significant increase in glucose entry occurred after 24 h but there was no significant change in propionate production or in the synthesis of glucose from propionate. It is concluded that the increase in glucose entry must arise from substrates other than propionate such as amino acids.