Role of Thyroid Hormones in Regulation of Sphingomyelin Metabolism in the Liver

N. A. Babenko^* and Yu. A. Natarova

Kharkov State University, Institute of Biology, pl. Svobody 4, Kharkov, 310077 Ukraine; fax: (0572) 35-2923; E-mail: Natalia.A.Babenko@kharkov.ua

^* To whom correspondence should be addressed.

Received November 25, 1998; Revision received March 3, 1999

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Inhibition of thyroid gland function in rats with mercasolil sharply decreased thyroxine and triiodothyronine levels in blood serum and increased acid sphingomyelinase activity and sphingomyelin content in liver. Thyroxine injected into hypothyroid rats normalized the sphingomyelin content, reduced the free ceramide content, and further increased the acid sphingomyelinase activity in liver. Thyroxine stimulated de novo sphingomyelin synthesis. Changing the thyroid status of the rats did not influence the free sphingosine content. Thyroxine blocks the accumulation of free sphingosine in the liver during activation of sphingomyelinases.

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KEY WORDS: liver, sphingomyelin, ceramides, sphingosine, sphingomyelinase, sphingomyelin synthesis, thyroid hormones

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