NMR studies of glucose and alanine utilization and maternal-embryonic nutrient transfer in the smooth dogfish, Mustelus canis

Captive dogfish, Mustelus canis, were injected with saline containing 13C-enriched alanine or glucose and permitted to metabolize labeled substrates. Blood plasma and other body fluids were analyzed using high field 13C nuclear magnetic resonance (NMR) spectroscopy. Both injected glucose and alanine are converted to lactate with alanine conversion more rapid than that of glucose. 13C-enriched alanine and lactate appear in intracapsular fluids after injection of 13C-enriched alanine into the maternal blood vascular system. Studies involving the injection of 13C-enriched nutrients into the maternal circulation can yield information on metabolite utilization and embryonic nutrition in viviparous matrotrophs.