Testicular development in bulls

In the present study our objectives were (1) to follow the temporal patterns of testicular LH and FSH receptor (LH-R and FSH-R) concentrations and affinity (Ka) during sexual maturation in bulls, to see if such patterns could explain the control of rapid testicular growth that occurs after 25 weeks of age, when serum gonadotropin concentrations are low; (2) to see if transformation growth factors (TGF- alpha and beta 1, 2 and 3) and interleukins (IL-1 and IL-6) are produced in the developing bovine testis and if their concentrations change during development; (3) to see if the onset of puberty could be hastened by treating bull calves subcutaneously (sc) with 3 mg of bLH (n=6) or 4 mg of bFSH (n=6) once every 2 days, from 4 to 8 weeks after birth. Mean LH-R concentrations decreased from 13 to 25 weeks of age and increased to 56 weeks of age (