Epinephrine sulfation in the forearm: arteriovenous differences in free and conjugated catecholamines.

Simultaneously drawn arterial and forearm venous levels of free and sulfate conjugated epinephrine and norepinephrine were measured in 8 subjects in order to study the role of skeletal muscle in catecholamine sulfation. A sensitive radioenzymatic assay was used. The average free epinephrine level was 46% lower in venous than in arterial blood (p less than 0.023) while average sulfated epinephrine level was 37% higher (p less than 0.016). These findings suggest that epinephrine sulfation is occurring in the forearm, most likely in skeletal muscle. The mean venous free norepinephrine level was 21% higher than the mean arterial level (p less than 0.055) presumably reflecting release from sympathetic nerve terminals. No evidence of norepinephrine sulfation or deconjugation in skeletal muscle was found.