Vol. 279, Issue 6, F1067-F1076, December 2000
Effects of experimental diabetes on renal IGF/IGFBP system
during neonatal period in the rat
A.
De la Puente*,
L.
Goya*,
S.
Ramos,
M. A.
Martín,
C.
Alvarez,
F.
Escrivá, and
A. M.
Pascual-Leone
Instituto de Bioquímica (Centro Mixto Consejo Superior
Investigaciones Científicas-Universidad Complutense de Madrid),
Facultad de Farmacia, Ciudad Universitaria, 28040 Madrid, Spain
Changes in the renal synthesis and
concentration of insulin-like growth factors (IGFs) and their
serum-binding proteins (IGFBPs) reported in insulin-deficient diabetes
mellitus may be implicated in the alterations of the kidney function
and morphology accompanying this disease. Most research on this subject
has been carried out in adult animals, as well as in peripubertal rats,
when the regulation of the IGF system is fully dependent on serum
growth hormone (GH). However, relevant differences in the regulatory
pathways of IGFs between adult and neonatal periods have been
described. To examine the response of the IGF/IGFBP system of
neonatal kidney to diabetes, renal IGF-I and -II and IGFBP-1, -2, and
-3 concentration and mRNA expression were determined in
streptozotocin-induced diabetic rat neonates. Diabetic neonates
exhibited a kidney weight-to-body weight ratio higher than that of
control rats, together with decreased IGF-I and increased IGF-II renal
concentration. Because kidney mRNA expression of both IGFs decreased,
the elevated renal IGF-II might result from increased uptake from
circulation. Insulin treatment recovered the altered IGFs to control
values, indicating the insulin-dependent regulation of IGFs in the
neonatal kidney. Elevated levels of the IGFBP-1 and -2 in the kidney of
diabetic neonates did not result from changes in their kidney mRNA
transcript expression, suggesting also a possible uptake from circulation.
insulin-like growth factors; insulin-like growth factor binding
proteins; neonatal kidney; diabetic kidney
*
A. De la Puente and L. Goya contributed equally to this article.
