Regulation of bovine adipose tissue metabolism during lactation. 3. Adaptations of hormone-sensitive and lipoprotein lipases.
Activity of lipases in adipose tissue during pregnancy and lactation was investigated in Holstein cows producing 5950 to 10,000 kg milk per 305 d. Activity of cytoplasmic lipoprotein lipase per gram of tissue was 97, 78, 140, 162, 179, and 235% of 30 d prepartum at -15, 15, 30, 60, 180, and 349 d about calving in yr 1. In yr 2, lipoprotein lipase per gram was 100, 259, 838, 791, and 430% of -30 d at -15, 30, 60, 120, and 180 d. Adaptations in activity per milligram cytoplasm protein were similar to those per gram tissue. Hormone-sensitive lipase per milligram protein was 161, 251, 114, 126, and 252% of -30 d when measured at 30, 60, 120, 180, and 240 d postpartum. Activity per gram of tissue responded similarly to the lactation state. Lipoprotein lipase is thus not a large contributor to the peripartum bovine adipose adaptation but is important in reattainment of body composition in mid and late lactation. Hormone-sensitive lipase is also increased during peak and midlactation. The pattern of elevated activity of these oppositely directed lipases reflects the dichotomous forces of milk fat production and body fat recovery acting on adipose tissue of lactating heifers.
D000273:Adipose Tissue / Q000201:enzymology*; D000818:Animals; D002417:Cattle / Q000378:metabolism*; D005260:Female; D007774:Lactation / Q000378:metabolism*; D008049:Lipase / Q000378:metabolism*; D008071:Lipoprotein Lipase / Q000378:metabolism*; D011247:Pregnancy
D008049:Lipase; D008071:Lipoprotein Lipase