Presence of follicle-stimulating hormone and luteinizing hormone in bull seminal plasma

Levels of FSH and LH were estimated in a crude powder of seminal plasma pooled from bulls. The FSH concentration in the seminal plasma was approximately 100 times greater than that in the circulation. The receptor-binding activity of LH in the seminal plasma was very low compared with that in blood. The FSH in bull seminal plasma was partially purified and found to be identical to ovine pituitary FSH in its ability to bind to bull testicular receptor, in its immunological reactivity and also in its chromatographic and electrophoretic properties. The partially purified LH in bull seminal plasma was more acidic than ovine pituitary LH as shown by disc electrophoresis. It showed low binding characteristics that were not parallel to pituitary LH in the specific radioreceptor assay. The significance of the inverse relationship between the levels of FSH and LH in seminal and blood plasma is unknown.