Analysis of the role of basic fibroblast growth factor in growth and differentiation of transplanted fetal rat paws and intestines.
Paws and intestinal segments from 16-day-old rat fetuses were transplanted bilaterally under the kidney capsule of adult female hosts and grown there for different periods of time. The direct effects of an antiserum to bovine basic fibroblast growth factor (bFGF) and of recombinant bFGF on growth and tissue differentiation in the transplants were evaluated by infusing them into the right renal artery via a catheter attached to an osmotic minipump. Infusion of the antiserum into the right kidney of intact hosts for 6 or 10 days did not affect either growth of the paws or bone differentiation in them. By contrast, the anti-FGF serum significantly inhibited the growth of intestinal transplants and caused slight retardation of villus differentiation. We presume that this inhibition resulted from neutralization of the bFGF produced within the transplants, as infusion of nonimmune rabbit serum had no such effects on the intestinal segments. In hypophysectomized hosts growth of both types of transplants was greatly reduced, and tissue differentiation was retarded, presumably reflecting low serum insulin-like growth factor-I levels. Infusion of the recombinant bFGF (5 micrograms/rat.day) into the hypophysectomized hosts stimulated growth of the paws and promoted ossification of the phalanges, but not the carpals. Intestinal growth was not affected by bFGF, and villus development was not restored. These results indicate that fetal rat structures are differentially dependent on and responsive to bFGF for growth and differentiation. These findings, when considered in relation to our previous results with transplanted 10-day-old rat embryos, indicate that growth and tissue differentiation during the embryonic period of rat development are more dependent on bFGF than are these processes in the fetal period.
Liu
L M
LM
Department of Integrative Biology, University of California, Berkeley 94720.
Russell
S M
SM
Nicoll
C S
CS
D000818:Animals; D005314:Embryonic and Fetal Development / Q000502:physiology*; D005346:Fibroblast Growth Factors / Q000494:pharmacology / Q000502:physiology*; D005528:Foot / Q000196:embryology* / Q000637:transplantation; D005552:Forelimb; D007016:Hypophysectomy; D007422:Intestines / Q000196:embryology* / Q000637:transplantation; D010012:Osteogenesis / Q000187:drug effects; D051381:Rats; D011994:Recombinant Proteins
D011994:Recombinant Proteins; D005346:Fibroblast Growth Factors