Fetal over- and undernutrition differentially program thyroid axis adaptability in adult sheep

Area of Science:

• Endocrinology
• Developmental programming
• Metabolic research

Background:

• Fetal nutrition influences long-term health.
• Early life nutrition impacts metabolic programming.
• Thyroid axis regulation is crucial for energy homeostasis.

Purpose of the Study:

• To investigate how fetal under- or overnutrition programs the thyroid axis.
• To determine the lasting effects on energy metabolism.
• To assess if early postnatal overnutrition modulates prenatal programming effects.

Main Methods:

• Twin-pregnant sheep were subjected to adequate (NORM), low (LOW), or high (HIGH) nutrition during the last trimester.
• Lambs received conventional (CONV) or obesogenic (HCHF) diets from 3 days to 6 months of age.
• Thyroid hormone levels, energy expenditure, and feed intake were assessed at 6 months and 2.5 years of age.

Main Results:

• Fetal malnutrition and mismatched nutrition altered thyroid hormone responses to thyroxine challenge.
• Early postnatal obesogenic diet reduced adult energy expenditure in NORM and HIGH groups.
• Adult feed intake capacity increased in NORM and LOW groups exposed to the obesogenic diet.

Conclusions:

• Late fetal malnutrition differentially programs the hypothalamic-pituitary-thyroid (HPT) axis.
• Early postnatal obesogenic diets have long-term effects on HPT axis function and energy metabolism.
• These programming effects have implications for adult adiposity risk.