Albumin and transferrin synthesis during development in the rat

Area of Science:

• Developmental Biology
• Biochemistry
• Proteomics

Background:

• Plasma proteins like albumin and transferrin are crucial for fetal and postnatal development.
• Understanding their synthesis rates and regulation provides insights into developmental processes.

Purpose of the Study:

• To compare the synthesis rates of albumin and transferrin during rat development.
• To investigate the expression of these proteins in fetal tissues and perinatal liver.
• To correlate synthesis rates with serum concentrations and explore discrepancies.

Main Methods:

• [(14)C]leucine incorporation was used to measure albumin and transferrin synthesis rates.
• Synthesis was assessed in fetal tissues (fetuses, membranes, placenta) and perinatal liver slices.
• Serum concentrations of albumin and transferrin were determined at different developmental stages.

Main Results:

• Albumin synthesis detected from day 13 gestation; transferrin synthesis from day 15.
• Transferrin synthesis occurred in membranes but not placenta; liver synthesis increased with age postnatally.
• Fetuses showed higher relative transferrin than albumin synthesis compared to postnatal animals.
• Serum protein concentrations increased before term while synthesis declined; postnatal changes showed discrepancies with synthesis rates.

Conclusions:

• Differential timing of albumin and transferrin synthesis suggests distinct developmental regulation.
• Postnatal discrepancies between synthesis and serum levels may be due to increased protein stability and uptake by non-synthesizing cells (e.g., liver hematopoietic cells).
• Developmental changes in protein stability and cellular uptake influence circulating levels of albumin and transferrin.