The removal and restitution of hair fat in the rat

Castrated male rats were washed with a solution of sodium lauryl sulphate and warm water using a standard technique. Examination of samples of hair clipped from one flank showed that about 50% of the total ether-extractable hair fat was removed. The rate of restitution of hair fat was then measured by clipping a further sample from the opposite flank of each rat after an interval. The plateau level was restored in about 8 days. There was no significant correlation with body weight either of the plateau level in unwashed rats or of the rate of build-up of lipid in washed rats. This result provides no justification for correcting levels of hair lipid for body weight.