Growth and maturation of testes in young coturnix and modification by exogenous FSH, LH, and testosterone--a stereologic evaluation.

Groups of coturnix males kept on continuous light from hatch were used in a study of testicular development. Testes were sampled from birds 4, 11, 18, 25, 32 days, and 4 months of age. Exogenous FSH at 1 and 2 mg., and LH and testosterone at 0.5 and 1.0 mg., were given daily for 3 days before the birds were killed for study at 4, 18, and 32 days of age. The following parameters were recorded: testes weights and volume, seminiferous tubular length and the ratio of length per mm.3 volume, supporting or Sertoli cell nuclear volume, volume of gonocytes, pre-leptotene spermatogonia, primary spermatocytes, and total intratubular volume. The stimulatory effect of exogenous LH and FSH on testes weight and volume, length/unit volume ratio of seminiferous tubules, and total intratubular component of the testes was most apparent at 4 days of age. The inhibitory effect of testosterone was significant at 18 and 32 days in all of these parameters. At 4 days, the 0.5-mg. level reduced the volume of the Sertoli cells and the gonial cell group. Full spermatozoa production was observed when the total length of the seminiferous tubules reached 30 m. It may be concluded from this study that young coturnix are similar to the chick in response to exogenous LH and FSH at 4 days of age. This response was observed even though the coturnix were on continuous light.