Protein synthesis by human fetal lung

Area of Science:

• Biochemistry
• Developmental Biology
• Pulmonary Medicine

Background:

• Alveolar surface layer contains proteins, carbohydrate-protein complexes, and phospholipids.
• Understanding lung protein synthesis alongside phospholipid biosynthesis is crucial for fetal lung development.

Purpose of the Study:

• To investigate human fetal lung protein synthesis during gestation.
• To analyze the characteristics of synthesized lung proteins.
• To determine the effect of hormones on fetal lung protein synthesis.

Main Methods:

• In vitro incubation of human fetal lung tissue (16-24 weeks gestation) with 14C-leucine.
• Fractionation of proteins using a 105,000 x g supernatant.
• Gel filtration chromatography (Sephadex G-200) to separate protein fractions.
• Analysis of radioactivity incorporation into different protein peaks (7S and 19S).

Main Results:

• Human fetal lung rapidly incorporated 14C-leucine into particulate and supernatant protein fractions.
• Three major peaks of radioactivity were identified after gel filtration.
• Synthesized proteins corresponding to 7S and 19S peaks were detected, with the 19S protein released into the medium.
• Prolactin and cortisone dose-dependently inhibited total protein synthesis, particularly affecting 19S and 7S fractions.

Conclusions:

• Human fetal lung synthesizes distinct proteins, including 7S and 19S fractions, in vitro.
• Hormonal regulation by prolactin and cortisone can significantly impact fetal lung protein synthesis.
• These findings contribute to understanding the biochemical development of the fetal lung.