Effect of tyrosine on the pars distalis of the rabbits hypothesis

The present study was conducted on 36 Newzeal and white rabbits assigned into three age groups of 2, 3 and 4 months, 12 rabbits for each group of the same age [6 males and 6 females]. For each sex, 4 rabbits were given orally a single dose of L-tyrosine, 100 mg/kg body weight and the other two rabbits, were left as control. The treated groups revealed an increase in the amount, size and the secretory activity of somatotrophs, lactotrophs and LH gonadotrophs, in addition to a marked increase in the amount, size and the secretory activity of thyrotrophs, adrenocorticotrophs and FSH gonadotrophs during the second month of age. From the present results it could be concluded that tyrosine acts as a growth promoting factor and a hormonal inducing factor, it can be used in rabbits for enhancing the puberty of both males and females. It could be recommended that tyrosine can be used on a large scale for regulating the reproductive cycle of males and females in large animals