Various clinical syndromes illustrate the essential role of insulin in
modulating somatic growth both in utero and after birth. The effect o
f insulin on growth is a consequence of direct effects transduced via
its homologous receptor and post-receptor signaling pathways and indir
ect effects on other modulators of growth, such as the growth hormone-
IGF axis. Recent insights into the post-receptor mechanisms of insulin
signaling provide a scientific framework for the distinction between
the traditional role of insulin as a major modulator of metabolism and
its role as a promoter of growth.