Transforming growth factor-alpha and the ontogeny of epidermal growth factor receptors in rat kidney.
Epidermal growth factor exerts potent receptor-mediated mitogenic effects on a variety of target cells in vitro, but its importance in normal organ development is not yet fully understood. We report that the specific high-affinity receptors for EGF/TGF-Alpha increase dramatically in late gestational rat kidney (from 2.3% at 16 days gestation to 6.4% at term) and then fall toward basal adult levels (< 1% binding) during the first week of post-natal life. This post-natal fall-off in EGF binding corresponds temporally to the period when replication of rat kidney DNA begins to slow (4-7 days of post-natal life). EGF mRNA is not detectable in rat kidney by Northern analysis until the second week of post-natal life, but high levels of transforming growth factor-alpha are demonstrable by specific radioimmunoassay in extracts of fetal kidney (52.2 +/- 8.2 pmoles/gram kidney) and amniotic fluid (4.49 +/- 0.75 pmoles/ml). We speculate that induction of EGF-receptors in fetal rat kidney may confer responsiveness to local transforming growth factor-alpha and dictate the rate of hyperplastic renal growth in the perinatal period.
Goodyer
P R
PR
Department of Pediatrics, McGill University, Montreal Children's Hospital, Quebec, Canada.
Fata
J
J
Goodyer
C G
CG
Guyda
H
H
D000653:Amniotic Fluid / Q000378:metabolism; D000818:Animals; D015152:Blotting, Northern; D004247:DNA / Q000378:metabolism; D004815:Epidermal Growth Factor / Q000235:genetics / Q000378:metabolism; D066246:ErbB Receptors / Q000378:metabolism*; D005865:Gestational Age; D007668:Kidney / Q000196:embryology* / Q000254:growth & development / Q000378:metabolism; D009929:Organ Size; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D016211:Transforming Growth Factor alpha / Q000502:physiology*
D012333:RNA, Messenger; D016211:Transforming Growth Factor alpha; D004815:Epidermal Growth Factor; D004247:DNA; D066246:ErbB Receptors