G. Harrap, S. Dolphin and L. Albiston.
Unilever Research Port Sunlight, Bebington, Wirral, UK
Study Information and Results:
Hair production requires high rates of protein synthesis within follicles and may be affected by amino acid availability.
The objective of the study was to determine whether age affects the concentration of free amino acids in hair roots in men from the UK.
Plucked vertex roots of 31 volunteers (mean age 40.6 yr.; range 21 – 73 yr.) with minimum androgenetic alopecia, were homogenised in an aqueous protease inhibitor solution to extract free amino acids which were analysed by HPLC of dabsyl derivatives.
Soluble protein was measured by a Coomassie Blue dye-binding method and used to correct amino acid levels for variations in amount of root material. 22 amino acids were detected in roots from all subjects. Glutamate, glutamine, aspartate, serine, glycine and alanine were the most abundant amino acids making up approximately 60% of the total. Cysteine and methionine were the least abundant amino acids.
The composition was distinct from that of free amino acids in serum and the total amino acid composition of hair fibres. Percentages of individual amino acids for subjects grouped above and below the mean age were not significantly different (p>0.05) for any amino acid. The total amount of free amino acid as ug per mg soluble protein declined significantly with age (p<0.05), this change being equivalent to a fall of 32.7% from 20 to 70 years of age.
It is concluded that amino acid concentrations fall in hair roots with age with little change in proportions.