Pigmentation And Hair Growth In Black Rats, As Modified By The Chronic Administration Of Thiourea, Phenyl Thiourea And Alpha-Naphthyl Thiourea

The study investigates the effects of chronic administration of thiourea, phenyl thiourea, and alpha-naphthyl thiourea on pigmentation and hair growth in black rats. It highlights that hair growth is intermittent and varies between individual hair follicles, with some being active while others are quiescent. This rhythmic alternation in activity is random in humans but regionally coordinated in many laboratory animals. The research builds on previous observations by Trotter (1924) and Forster (1929) regarding the patterns of hair growth and the use of different animals to study hair growth stimulants.