Free Amino Acids and Protein in Rete Testis Fluid, Vas Deferens Plasma, Accesory Sex Gland Fluid, and Seminal Plasma of the Conscious Bull

Fluids and spermatozoa were collected by cannulae in the rete testis and vas deferens, by ejaculation of these bulls prior to surgery, and by ejaculation of bilaterally vasoligated bulls. Sixteen free amino acids were identified in each of the sperm-free fluids: fete testis fluid, vas deferens plasma, accessory sex gland fluid, and seminal plasma. Glutamate was the predominant amino acid in fete testis fluid, 1.12 ~moles (37%); vas deferens, 24.88 /zmoles (56%); and seminal plasma, 1.01 /zmoles per milliliter (38%). However, in accessory sex gland fluid the predominant amino acid was alanine, 0.32 /,moles per milliliter (26%). Glutamate, glycine, alanine, serine, aspartate, and threonine together accounted for at least 73% of the free amino acids in each fluid. The concentration of the combined free amino acid pool in vas deferens plasma was greater (P < 0.01) than in other fluids, but the amount of most free amino acids entering the epididymis daily in fete testis fluid was greater than the amount recovered in vas deferens plasma. Protein in accessory sex gland fluid was higher (P < 0.01) than that in rete testis fluid or in vas deferens plasma.