Int. J. Dev. Biol. 41: 315 - 318 (1997)

Vol 41, Issue 2

Special Issue: Vertebrate Development in vitro

Investigations into mechanisms of amino acid supply to the rat embryo using whole-embryo culture

Published: 1 April 1997

D A Beckman, J B Lloyd and R L Brent

Department of Pediatrics, Jefferson Medical College, Thomas Jefferson University, Philadelphia, Pennsylvania, USA. djbeck@voicenet.com

Abstract

The technique pioneered by D.A.T. New for the in vitro culture of early post-implantation rat embryos has been used to study nutritional mechanisms during early organogenesis. The results indicate that the principal route for amino acid supply to the 8.5- to 11.5-day embryo involves the endocytosis of proteins into cells of the visceral yolk sac endoderm, their digestion in lysosomes, and transmission of the amino acids to the growing embryo. Free amino acids constitute a comparatively unimportant source. Inhibition of either endocytosis or intralysosomal proteolysis diminishes amino acid supply to the embryo, and this can result in embryonic death or maldevelopment during organogenesis.