The lipoprotein lipase activity of brown adipose tissue during early post-natal development of the normal and hypothyroid rat.
The heparin-releasable LP lipase activity of BAT (brown adipose tissue), and the TG (triglyceride) content of plasma were determined in normal and hypothyroid rats during early post-natal development. The TG content of plasma increased sharply after the onset of suckling and decreased during the weaning period in normal rats, while it stayed at a high level in hypothyroid rats. LP lipase activity was maximal during the perinatal period and decreased later, being practically undetectable in one month old control animals; in contrast, LP lipase activity was still present in cretin rats at this age. The effects of several forms of treatment were also tested in weaned rats: a high-fat diet was not able to maintain the high LP lipase activity of suckling rats, but the activity was high if the animals were bred at a cold temperature. Thyroxine injections had no effect. These results are discussed in terms of the possible factors regulating the LP lipase activity in BAT.
D002001:Adipose Tissue, Brown / Q000187:drug effects / Q000201:enzymology*; D000818:Animals; D000831:Animals, Newborn; D003080:Cold Temperature; D004041:Dietary Fats; D005260:Female; D006493:Heparin; D007037:Hypothyroidism / Q000139:chemically induced / Q000201:enzymology*; D007774:Lactation; D008071:Lipoprotein Lipase / Q000378:metabolism*; D011247:Pregnancy; D011441:Propylthiouracil; D051381:Rats; D013974:Thyroxine / Q000494:pharmacology; D014280:Triglycerides / Q000097:blood
D004041:Dietary Fats; D014280:Triglycerides; D011441:Propylthiouracil; D006493:Heparin; D008071:Lipoprotein Lipase; D013974:Thyroxine