Lipoprotein lipase activity in human and guinea-pig placenta

Area of Science:

• Biochemistry
• Reproductive Biology
• Enzymology

Background:

• Placental tissue possesses enzymatic activity crucial for nutrient transfer and metabolism.
• Lipases are key enzymes involved in lipid hydrolysis and transport.

Purpose of the Study:

• To characterize and compare lipase activity in human and guinea-pig placentas.
• To investigate the properties and potential types of lipases present in placental tissue.

Main Methods:

• Lipase activity was quantified by measuring the release of 3H-labeled fatty acids from a triacylglycerol substrate.
• Tissue extracts and incubated tissue fragments were used to assess enzyme activity.
• Effects of cold acetone, sodium chloride, heparin, and insulin on lipase activity were examined.

Main Results:

• Significant lipase activity was detected in both human (1.6 U/g) and guinea-pig (87.1 U/g) placental tissues.
• Acetone treatment reduced activity by 70% (human) and 56% (guinea-pig).
• Heparin stimulated lipase release from human placenta, but not significantly from guinea-pig placenta; insulin had no effect.

Conclusions:

• Human and guinea-pig placentas contain at least two distinct lipase enzymes.
• A significant portion of the total placental lipase activity exhibits characteristics of lipoprotein lipase.
• The findings suggest species-specific differences in placental lipase regulation and function.