Lysosomal acid lipase (LAL), the enzyme which hydrolyzes lipoprotein cholesteryl esters, is under thyroid hormone regulation in experimental animals. To evaluate whether human LAL is also under thyroid regulation, we measured mononuclear leukocyte LAL activity in 31 hypothyroid, hyperthyroid, and euthyroid children under treatment. LAL activity was positively correlated with serum T3 and serum T4 levels, and was significantly higher in hyperthyroid children than in those who were hypothyroid. In another study, 5 adult euthyroid males were given 50 micrograms L-T3 every 8 h for 4 days. Their LAL activities increased significantly after treatment. The data suggest that LAL activity in man, as in experimental animals, is influenced by thyroid hormone status. Hormonal control of LAL activity may be important in the regulation of human cholesterol metabolism.
Effect of thyroid hormones on human mononuclear leukocyte lysosomal acid lipase activity. - PubMed - NCBI
In adults with myxedema, however, normal or increased ester :total cholesterol ratio occurs. The rise in serum cholesterol is greater than that of phospholipid, and the cholesterol:phospholipid ratio is increased.8 An increase of lowdensity (beta) lipoproteins, both in spontaneous and in induced myxedema, is largely in the Sf 0-12 moiety but is found also in fractions Sf 12-400; all of the abnormalities are reversed by the administration of desiccated thyroid.9' 10 The lipoprotein abnormality may be reversed with very small doses of desiccated thyroid (15 to 30 mg.)."-
https://www.ahajournals.org/doi/pdf/10.1161/01.CIR.22.3.464
Effect of thyroid hormones on human mononuclear leukocyte lysosomal acid lipase activity. - PubMed - NCBI
In adults with myxedema, however, normal or increased ester :total cholesterol ratio occurs. The rise in serum cholesterol is greater than that of phospholipid, and the cholesterol:phospholipid ratio is increased.8 An increase of lowdensity (beta) lipoproteins, both in spontaneous and in induced myxedema, is largely in the Sf 0-12 moiety but is found also in fractions Sf 12-400; all of the abnormalities are reversed by the administration of desiccated thyroid.9' 10 The lipoprotein abnormality may be reversed with very small doses of desiccated thyroid (15 to 30 mg.)."-
https://www.ahajournals.org/doi/pdf/10.1161/01.CIR.22.3.464