Although prostatic cancer is evident late in life, pathological evidence suggests this disease is initiated earlier in life. As prostatic cancer is an endocrine associated disease and as adult hormone profiles are established during puberty, it was of interest whether difference in pubertal hormone levels occurred in populations at low or high risk for prostatic cancer. Accordingly we have investigated the hormone profiles in rural Black South African and urban white boys during puberty. It has been suggested that the timing of puberty is modified by environmental factors and that there is a concomitant control of gonadotrophin release and food intake by CNS-peptide hormones. It is therefore postulated that dietary factors during puberty modify the gut-CNS peptide hormones which in turn control the hypothalamic-pituitarytesticular axis. Distinct difference in plasma androgen and gonadotrophins between the two races are in part concordant with a modification of CNS-peptide hormones by environmental factors during puberty.