The importance of diffusion and perfusion in terms of oxygen transport was evaluated by chronically altering environmental O2 availability (hypoxia or hyperoxia) and blood O2 content (carbon monoxide) through development in Xenopus laevis. Oxygen consumption (M(O(2))), individual wet mass, heart rate (fh), and stroke volume (SV) were measured in animals raised from eggs to pre-metamorphic climax while maintained at 11, 21 and 35 kPa O2, combined with and without 2 kPa carbon monoxide. Additionally, cardiac output (Q), and a recently defined O2 consumption/transport quotient (M(O(2)).Q-1(O(2))) were calculated. Wet mass, M(O(2)), and fh, were not significantly different between controls and experimental treatments at any developmental stage. However, with hemoglobin oxygen transport blocked by carbon monoxide, the exposed larvae showed an increased SV, Q and M(O(2)).Q-1(O(2)). Combined, these data suggest that in spite of impaired blood O2 convection, normal aerobic metabolism was maintained, indicating that direct diffusion of O2 plays an important role in supplying oxygen during early development. Copyright (C) 1998 Elsevier Science B.V.
- African clawed frog (Xenopus laevis)
- Development, egg
- Egg, amphibian, O transport
- Oxygen, transport
ASJC Scopus subject areas
- Pulmonary and Respiratory Medicine