The role of methionine and cystine in the growth and viability of secondary hair follicles of the Cashmere goat in vitro

Abstract

A supply of sulphur-containing amino acids is essential for the growth of hair fibre in animals.The main sulphur-containing amino acid quantitatively required for the synthesis of fibre protein is cystine or its monomeric form cysteine,which may be absorbed from the digestive tract or converted from methionine via the transulphuration pathway.The predominant sites of the transulphuration pathway in ruminants are the liver (Radcliffe and Egan,1978)and the heterogenous system in the skin (Downes et al,1964).The aims of the study were to determine the importance of the supply of cystine and methionine for the growth and viability of the cashmere secondary hair follicle in vitro and to investigate whether cystine could successfully be replaced by methionine in this homogenous system.