Effect of hypothyroidism on blood lipid concentrations in horses.

The research paper explores how hypothyroidism, a condition caused by insufficient thyroid hormone production, impacts blood lipid concentrations in horses. Procedures involved inducing hypothyroidism in five healthy mares and monitoring changes in lipid levels for four weeks. The results demonstrated stark increases in very low-density lipoprotein (VLDL), low-density lipoprotein (LDL), serum triglyceride (TG), and total cholesterol (TC), alongside a decrease in nonesterified fatty acid (NEFA) levels. The study suggests blood lipid concentrations could potentially detect naturally occurring hypothyroidism in horses.

Research Methods

• The research started with five adult mares confirmed to be euthyroid, meaning they had normal thyroid function.
• A thyroidectomy, the surgical removal of the thyroid gland, was performed on these mares to induce hypothyroidism.
• After the surgery, the presence of hypothyroidism was then confirmed in all the mares.
• The researcher tracked selected blood lipid variables both before and weekly after the induction of hypothyroidism for a period of 4 weeks.
• The plasma concentrations of lipid variables such as VLDL, LDL, serum TG, TC, and NEFA were measured, as well as the composition of VLDL and LDL.

Research Findings

• The study identified significant increases in mean plasma concentrations of VLDL and LDL following the thyroidectomy.
• By the fourth week after surgery, VLDL and LDL concentrations in the blood had increased ninefold and threefold, respectively, compared to baseline measurements.
• Changes to the composition of VLDL and LDL were noticed, particularly an increase in TG in VLDL and LDL, while free cholesterol and cholesterol ester content decreased.
• A trend of increased serum concentrations of TG and TC and decreased blood concentration of NEFA was also noted following thyroidectomy.

Conclusions

• The findings from this research demonstrate that hypothyroidism significantly alters the blood lipid concentrations in horses.
• Detectable changes included a notably high VLDL concentration, an increased presence of TG-rich VLDL, and increased serum concentrations of TG and TC.
• Furthermore, the study noted a visible decrease in the blood concentration of NEFA after the surgery to induce hypothyroidism.
• The researchers suggested that the examination of blood lipid concentrations could be a useful method for the detection of naturally occurring hypothyroidism in horses.