A sex difference of the concentrations of gonadotropins, its subunits and sex steroids in cord veins.

In order to elucidate the sex difference of cord blood hormones, concentration of hCG, hCG-alpha, hCG-beta, hLH, hFSH, estradiol (E2), progesterone (P) and testosterone (T) in cord veins were assayed by radioimmunoassays. Mean concentrations of cord vein hCG, hCG-alpha and hLH were significantly higher in female than in male, but those of hFSH and T were significantly higher in male than in female. Male and female cord vein levels of hCG-beta, E2 and P were not significantly different and hCG-beta and hFSh levels in cord veins at term are low in both sexes. These lower concentrations of hLH in male may be a result of the feedback inhibitory action by the higher concentrations of T in male at term. These data suggest a sex difference in the synthesis and secretion of gonadotropins by the pituitary gland in the human foetus at term.