Delay of puberty onset in males due to suppression of growth hormone.

Infection with Spirometra mansonoides at 22 days of age was associated with delayed sexual maturation in the male rat. Balanopreputial separation occurred at 46.7 +/- 0.8 days in controls and at 50.6 +/- 0.9 days in worm-treated rats (p less than 0.02). This was accompanied by a delay in the normal prepubertal testicular and seminal vesicle weight increases. LH remained normal but serum FSH was depressed as early as 25 days of age. The castration response in worm-treated rats was comparable to that of controls, when the FSH levels were normalized as percentages of resting level. The LH response to castration was diminished. The acute FSH and LH response to GnRH was normal and pituitary stores of gonadotrophin, as estimated by radioimmunoassayable concentrations of FSH and LH, were normal. It can be concluded that puberty onset in males is not linked to body weight gain pe se, and that the absence of endogenous GH secretion affects both sexual maturation and gonadotrophin secretion in the prepubertal period.