Related Experiment Videos
Renal clearance measurements of electrolytes in embryonic chickens
N B Clark1, J Q Feng, M J Murphy
1Department of Physiology and Neurobiology, University of Connecticut, Storrs 06269.
Insights
Chick embryo kidneys conserve calcium by day 15, mirroring post-hatchling function. Renal ion handling shifts during development, with significant changes in filtration and excretion rates observed.
Area of Science:
- Developmental biology
- Comparative physiology
- Renal physiology
Background:
- Embryonic development involves significant physiological adaptations.
- Kidney function is crucial for maintaining ion homeostasis during development.
Purpose of the Study:
- To investigate changes in plasma ion concentrations in chick embryos.
- To examine the development of renal function and ion handling during chick embryogenesis.
Main Methods:
- Analysis of plasma ion concentrations (calcium, phosphate, sodium, potassium, magnesium, sulfate) at 9, 12, and 15 days of incubation.
- Measurement of glomerular filtration rates and urine flow rates relative to body weight.
- Calculation of renal clearance values for various ions.
Main Results:
- Plasma calcium and phosphate increased significantly from day 9 to day 15.
- Glomerular filtration and urine flow rates decreased significantly relative to body weight.
- Renal calcium excretion decreased from 16% to 4% by day 15, indicating conservation.
Conclusions:
- The embryonic chick kidney conserves calcium by late embryogenesis.
- Sodium and sulfate also appear to be conserved, while phosphate, potassium, and magnesium are largely excreted.
- Renal ion handling is largely similar between the mesonephric and metanephric kidneys, except for calcium.
Abstract:
Plasma ion concentrations and renal functions were examined in chick embryos after 9, 12, and 15 days of incubation. Plasma calcium and phosphate values rise steadily and significantly between days 9 and 15 of development. Values of other plasma ions (sodium, potassium, magnesium, sulfate) remain more or less the same during this developmental period. Glomerular filtration rates and urine flow rates decline steadily and significantly during this period of embryogenesis when expressed relative to body weight. Renal clearance values of calcium decrease between day 9 (16% of filtered calcium is excreted) and day 15 (4%). The latter value is the same as in birds after hatching and indicates that calcium is being conserved by the kidney of the chick during late embryogenesis. Other ions that appear to be conserved by the embryonic kidney are sodium and sulfate, whereas high percentages of filtered phosphate, potassium, and magnesium are excreted. Except for calcium, there was no significant difference between the renal handling of ions by the mesonephric kidney (functional in 9 day embryos) and the metanephric kidney (predominant in the 15 days embryos).