Long-term variations in plasma gonadotropins in early castrated male rabbits.

LH and FSH levels were determined by RIA in plasma samples collected every 10 days from 30 to 90 days and at 4, 5 and 6 months in control male rabbits and in rabbits castrated at 30 days of age. At all stages studied gonadotropin levels were significantly increased in castrates. Mean LH levels were not influenced by age in controls or in castrates. Mean FSH levels were age dependent and increased during sexual maturation in both groups. The results showed that the secretion of FSH, but not that of LH, may be stimulated during prepubertal and pubertal stages in males where steroidal inhibition is absent.