Endocrinology, Vol 124, 3077-3082, Copyright © 1989 by Endocrine Society

ARTICLES

Effects of insulin-like growth factors I and II on growth and differentiation of transplanted rat embryos and fetal tissues

L Liu, S Greenberg, SM Russell and CS Nicoll
Department of Physiology-Anatomy, Cancer Research Laboratory, University of California, Berkeley 94720.

The objective of our study was to obtain comparative information on the roles of insulin-like growth factors (IGFs) I and II in the growth and differentiation of rat embryos and fetuses in an in vivo experimental system. Ten-day-old rat embryos or 16-day-old fetal rat paws were transplanted under the capsule of both kidneys of syngeneic hosts, where they grew rapidly, and tissue differentiation occurred in an essentially normal manner. Infusion of a rabbit antiserum to human (h) IGF-I for 6 days into the renal artery of one kidney caused only a slight inhibition (approximately 20%) of growth of transplanted embryos on that kidney. However, 9 days of treatment with the antiserum caused highly significant growth retardation of transplanted embryos by 40- 45%. Exposure of fetal paws to the same antiserum for 9 days inhibited their growth by 27%. Infusion of synthetic hIGF-II or partially purified rat IGF-II [(MSA)multiplication-stimulating activity], for 6 days stimulated the growth of embryo transplants directly, and MSA was more effective than hIGF-II. By contrast, infusion of purified natural hIGF-I did not promote their growth. Growth of fetal paw transplants in hypophysectomized (HX) hosts was reduced by 70% compared to that in intact hosts. In the HX hosts infusion of the MSA was more effective than the hIGF-I at promoting the growth of paw transplants. Both MSA and IGF-I promoted ossification in the fetal paws in the HX hosts. These results suggest that both IGFs could be involved in regulating the growth and differentiation in prenatal rats, and IGF-II may be the more effective of the two factors as a growth-promoting agent in utero.

This article has been cited by other articles:

				G. A. Braems, L.-J. Yao, K. Inchley, A. Brickenden, V. K. M. Han, A. Grolla, J. R. G. Challis, and F. Possmayer Ovine surfactant protein cDNAs: use in studies on fetal lung growth and maturation after prolonged hypoxemia Am J Physiol Lung Cell Mol Physiol, April 1, 2000; 278(4): L754 - L764. [Abstract] [Full Text] [PDF]

				G. Schwartz, M. Warren, K Sakano, J. Szabo, S. Kessler, A Pashapour, R. Gress, and J. Perdue Comparative effects of insulin-like growth factor II (IGF-II) and IGF- II mutants specific for IGF-II/CIM6-P or IGF-I receptors on in vitro hematopoiesis Stem Cells, May 1, 1996; 14(3): 337 - 350. [Abstract]

				D A Rappolee, K S Sturm, O Behrendtsen, G A Schultz, R A Pedersen, and Z Werb Insulin-like growth factor II acts through an endogenous growth pathway regulated by imprinting in early mouse embryos. Genes & Dev., June 1, 1992; 6(6): 939 - 952. [Abstract] [PDF]