THE EFFECTS OF TERATOGENIC ANTISERA ON PROTEIN SYNTHESIS AND DEGRADATION BY THE CULTURED RAT CONCEPTUS

Abstract

Rat embryo culture was initiated on the 10th day of gestation to study embryonic site protein synthesis in normal and pathologic states. Three culture media were employedsrat serum, serum plus teratogenic sheep anti-rat visceral yolk sac (VYS) serum, or rat serum plus normal sheep serum. Two studies were performed: a) 3H-leucine was added to produce incubation periods of 20 min. to 24 hr.; and after an initial period of culture in the presence of 3H-leucine to obtain a constant precursor specific radioactivity, culture was continued in the absence of 3H-leucine for a total of 1-30 hr. Embryos, VYS and culture media were analysed for total radioactivity and 3H-leucine specific radioactivity in the protein-bound and free amino acid fractions. The results suggest that: a) anti-VYS serum inhibited protein synthesis by the embryo and VYS but had no detectable effect on protein degradation; b) anti-VYS serum increased intracellular labeled leucine concentration. The teratogenic mechanism of anti-VYS serum appears to involve both the suppression yolk sac amino acid nutritive support of the embryo and the inhibition of the utilization of amino acids by the embryo for protein synthesis. These techniques provide us with the ability to determine the amino acid requirements which will support normal organogenesis and to quantitate the amino acid deprivation which will result in embryopathology. (Supported by NIH)