In vitro noradrenaline accumulation by sheep skin: partial characterization and localization

Previous studies from this laboratory have implicated the sympathetic neurotransmitter noradrenaline (NA) in regulation of wool growth. The current study was undertaken to investigate [3H]NA accumulation and its localization by Merino skin, and to determine the effects of gonadal and glucocorticoid steroids on such uptake. The presence of an active uptake system was demonstrated and the process was partially characterized in terms of its magnitude, time course, concentration dependence and requirement for various nutrient and ionic factors. The uptake was seen to occur predominantly into cocaine- and 6-hydroxydopamine-sensitive sites in skin from various body regions of Merino sheep. None of three steroids tested in vivo or in vitro was seen to influence the uptake process. These results do not enable us to correlate the observed [3H]NA uptake process with the previously reported effects of NA on wool growth.