Membrane distribution and carotenoid content in human colostrum.
Daily colostrum samples from 5 donors were fractionated into fat globules, non-lipid phase (skim milk), and cells. These and portions of the intact samples were assayed for protein, phospholipid and cholesterol, the latter two serving as criteria of membrane. The intact samples were also analyzed for total lipid and carotenoids, and skim milk phases for protein patterns by gel electrophoresis. Membrane material was highest in the first two daily samples with substantial amounts in both fat globule and skim milk phases; quantities declined over the 5-day sampling period, particularly in the skim milk. Membrane in the cell fraction was less than 1% of total. In first colostrum there was more than twice as much membrane material as in mature milk (greater than 1 month of lactation), and seven times as much in the skim milk phase. The protein pattern and carotenoid content of colostrum changed markedly during the sampling period. The elevated carotenoids in colostrum are attributed to mobilization of lipids stored in the breast. Based on pigmentation and density, colostrum contains two kinds of fat globules.
D002338:Carotenoids / Q000032:analysis*; D002458:Cell Fractionation; D002784:Cholesterol / Q000378:metabolism; D003126:Colostrum / Q000032:analysis / Q000378:metabolism*; D004591:Electrophoresis, Polyacrylamide Gel; D005260:Female; D006801:Humans; D008563:Membrane Lipids / Q000378:metabolism*; D008565:Membrane Proteins / Q000378:metabolism; D010743:Phospholipids / Q000378:metabolism; D011247:Pregnancy
D008563:Membrane Lipids; D008565:Membrane Proteins; D010743:Phospholipids; D002338:Carotenoids; D002784:Cholesterol