[Secretion and Sex differences in cord serum growth hormone levels of the human fetus (author's transl)].

Cord venous growth hormone (GH) and somatostatin levels were measured by radioimmunoassay in 86 infants and 11 anencephalic infants. 1) Cord GH levels were 69.2 +/- 20.2 ng/ml (N = 6, gestational weeks (GW) : 21-30W, mean +/- S.D.), 31.5 +/- 24.3 ng/ml (N = 11, GW : 31-36W), and 17.6 +/- 8.9 ng/ml (N = 71, GW: 37-41). In anencephalic infants, cord GH levels were significantly lower (2.3 +/- 1.4 ng/ml) than those in preterm and fullterm infants. 2) In fullterm infants, cord GH levels of small infants (19.2 +/- 9.2 ng/ml, N = 33, birth weight less than 3,250g) were significantly higher than that of large infants (15.1 +/- 8.1 ng/ml, N = 38, birth weight greater than of equal too 3,250g). On the other hands, cord somatostatin levels were relatively lower in small infants than in large infants. 3) There was a significant difference between male cord GH levels (20.6 +/- 8.9 ng/ml, N = 35) and female cord GH levels (14.6 +/- 8.0 ng/ml, N = 36). These results suggest that fetal GH secretion is suppressed by GH inhibiting factor (somatotropin release inhibiting factor) from mid gestation toward term and there is a sex difference of fetal GH secretion in fullterm fetus.