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VOL. 71 (4), 765-782, 2005 OLD HORMONES OF THE INSULIN...

consistent results were observed with IGF-II and the IGF-I receptor
mRNAs, neither of which appeared to change in proliferating neural
stem cells under proliferative conditions, whether or not they had
the IGF-I gene knockout (Fig. 7). Nevertheless, this finding does not
exclude the possibility that IGF-II or the IGF-I receptor could be up-
regulated at the posttranscriptional level.

In neurogenesis, therefore, the presence of proinsulin as well as
IGF-I and II mRNAs suggests that all three proteins may play a role
but the most clear effect observed, thus far, is the essential action of
IGF-I in neural differentiation, at least in the mouse olfactory bulb.

AKNOWLEDGEMENTS

We thank Dr. Jose Serna for contributing the immunofluorescen-
ce images in Fig. 2, Dr. Alicia Mansilla for critical reading of the
manuscript and past and present members of the laboratory for
their continuing efforts. Studies in the laboratory are funded by the
Spanish Ministry of Education and Science, Comunidad de Madrid
and Red de Grupos RGDM G03/212 from the Instituto de Salud
Carlos III (Spain). The Ramón y Cajal contract to C.H-S. was awar-
ded by the MEC. This review is a modified version of the conference
presented by F. de Pablo on November 4, 2004 with the occasion of
becoming Académica Correspondiente of the Academy.

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