
serum chorionic 'growth hormone-prolactin' and serum pituitary
growth hormone in mother and fetus at term.
chorionic 'growth hormone-prolactin' (cgp) and
pituitary hgh were measured in
maternal and fetal blood obtained simultaneously
at term from 29 pregnant women
and their fetuses utilizing sensitive radioimmunoassay
procedures.  the mean concentration
of serum cgp in maternal venous blood
was 5.6  g/ml (sem0.39) whereas
in umbilical venous serum the mean concentration
was 0.019  g/ml (sem 0.003),
a 300-fold difference.  contrariwise, the mean
concentration of serum hgh in maternal
serum was 5.9 m g/ml (sem 0.52) and
in umbilical venous serum the level
was 33.5 m g/ml (sem 4.6).  the ratio of serum
cgp/hgh in maternal venous serum
was 1076 in contrast to 0.57 in umbilical venous
serum.  the findings strongly suggest
that cgp is secreted by the syncytiotrophoblast
almost exclusively in a unidirectional
manner into the maternal circulation.
further, it is unlikely that an appreciable
exchange of hgh occurs between the
maternal and fetal circulations.  the
data support the view that the growth hormone-like
metabolic changes observed in
pregnancy are attributable to the effects of cgp
and are consistent with the hypothesis
that cgp is an important metabolic hormone
of pregnancy exerting its actions
on the mother and possibly the placenta, but only
indirectly on the fetus.
