Biologically active chorionic gonadotropin: synthesis by the human fetus

Area of Science:

• Endocrinology
• Developmental Biology
• Molecular Biology

Background:

• The alpha subunit is common to all human glycoprotein hormones.
• Previous studies indicated fetal kidney and liver synthesize beta chorionic gonadotropin.

Purpose of the Study:

• To investigate the synthesis of the common alpha subunit of glycoprotein hormones in human fetuses.
• To determine if fetal kidney and liver can synthesize bioactive chorionic gonadotropin.
• To explore the potential role of the human fetus in metabolic homeostasis.

Main Methods:

• Analysis of protein synthesis in fetal kidney, liver, lung, and muscle tissues.
• Assessment of chorionic gonadotropin bioactivity through binding assays with mouse Leydig cells.
• Measurement of testosterone synthesis as a biological response.

Main Results:

• Human fetal kidney and liver synthesize and secrete the common alpha subunit of glycoprotein hormones.
• Fetal lung and muscle tissues do not synthesize this subunit.
• Synthesized chorionic gonadotropin from fetal kidney and liver demonstrated bioactivity, binding to Leydig cells and stimulating testosterone production.

Conclusions:

• The human fetus, specifically kidney and liver, possesses the capability to synthesize and secrete functional glycoprotein hormones.
• The bioactivity of chorionic gonadotropin produced by the fetus suggests its potential involvement in regulating fetal development and metabolic processes.
• These findings highlight a previously unrecognized endocrine function of the human fetus, contributing to its own metabolic homeostasis.