The left superior cervical ganglion was removed from 18 sheep. The animals were exposed to a cold environment and ear temperature was monitored to indicate the likely release of noradrenaline in the skin of the cheeks or adrenaline from the adrenals. With respect to the sympathectomized side, a reduction in ear temperature on the unoperated side was associated with lowered mitotic rate at the unoperated cheek site (P < 0.026). However, when the temperature of the unoperated side was not lowered, mitotic rate was not consistently lower on one side with respect to the other. Physiological levels of noradrenaline therefore mimicked the effects observed during the pharmacological studies, and the catecholamines may therefore play an important role in the regulation of wool growth.
DR Scobie, PI Hynd and BP Setchell
Australian Journal of Agricultural Research 45(6) 1159 - 1169
Full text doi:10.1071/AR9941159
© CSIRO 1994