Brain beta-hydroxybutyrate utilization in neonatal hypothyroidism in rats

Area of Science:

• Neuroscience
• Developmental Biology
• Endocrinology

Background:

• Neonatal hypothyroidism is associated with impaired brain development and altered lipid metabolism.
• Beta-hydroxybutyrate (BOHB) is a crucial energy substrate for the neonatal brain.

Purpose of the Study:

• To investigate the in vitro and in vivo utilization of 14C-beta-hydroxybutyrate (BOHB) by the brain in neonatal rat pups with experimentally induced hypothyroidism.
• To understand the impact of hypothyroidism on BOHB metabolism and brain lipid synthesis during early development.

Main Methods:

• Rat pups were made hypothyroid using propylthiouracil in the maternal diet during gestation and lactation.
• In vitro studies measured BOHB oxidation to CO2 and incorporation into brain lipids.
• In vivo studies assessed the incorporation of BOHB into brain lipids at different ages.

Main Results:

• In vitro BOHB oxidation was lower at 14 and 21 days but higher at 35 days in hypothyroid pups compared to controls.
• In vitro incorporation of BOHB into brain lipids was significantly higher in hypothyroid pups at all measured ages (14, 21, and 35 days).
• In vivo incorporation of BOHB into brain lipids was significantly lower in hypothyroid pups at 14 and 21 days.

Conclusions:

• Hypothyroid neonatal pups exhibit altered BOHB utilization patterns, with potentially normal or increased in vitro lipid synthesis capacity.
• Reduced in vivo BOHB incorporation suggests impaired substrate availability or transport, contributing to decreased brain lipid content in neonatal hypothyroidism.
• These findings highlight a potential mechanism for the neurodevelopmental deficits observed in neonatal hypothyroidism.