Developmental regulation of hormone-sensitive lipase mRNA in the rat: changes in steroidogenic tissues.
The hydrolysis of triglycerides and cholesteryl esters stored within cells is mediated by the enzyme, hormone-sensitive lipase. In adipose tissue and heart, hormone-sensitive lipase primarily hydrolyzes stored triglycerides to free fatty acids, while in steroidogenic tissues, it principally converts cholesteryl esters to free cholesterol for steroid hormone production. To determine whether hormone-sensitive lipase is under tissue-specific, developmental regulation, the steady state levels of hormone-sensitive lipase mRNA were determined in normal rats from late fetal life through 2 years of age. Hormone-sensitive lipase mRNA levels did not appear to vary in adipose tissue from epididymal fat pads obtained from animals between 3 weeks and 2 years of age. In heart, hormone-sensitive lipase mRNA levels were lowest in the fetus increased rapidly within the first day postnatally, and then gradually increased to stable adult levels by 2 months that were 3-fold higher than observed in fetal rats. Steady state mRNA levels of hormone-sensitive lipase in the adrenals were lowest in fetal rats, increased 4-fold during the first day and peaked at levels that were 9-fold higher by the end of the first week. Thereafter, levels fell and remained 3- to 4-fold higher than at birth throughout adult life. Hormone-sensitive lipase mRNA was undetectable in testes before 4 weeks of age and increased 25-fold to stable adult levels between 4 and 12 weeks. Thus, hormone-sensitive lipase is differentially expressed and regulated in a tissue-specific fashion during development and aging.
Kraemer
F B
FB
Department of Medicine, Stanford University School of Medicine, CA 94305.
Tavangar
K
K
Hoffman
A R
AR
D000199:Actins / Q000502:physiology; D000273:Adipose Tissue / Q000201:enzymology*; D000311:Adrenal Glands / Q000201:enzymology; D000818:Animals; D015152:Blotting, Northern; D005333:Fetus / Q000201:enzymology; D015971:Gene Expression Regulation, Enzymologic; D008049:Lipase / Q000235:genetics*; D008297:Male; D009206:Myocardium / Q000201:enzymology; D009928:Organ Specificity; D012333:RNA, Messenger / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains; D002787:Sterol Esterase / Q000235:genetics*; D013737:Testis / Q000201:enzymology
D000199:Actins; D012333:RNA, Messenger; D002787:Sterol Esterase; D008049:Lipase