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Measurement of de novo lipogenesis in humans during lactation
Author(s) -
Mohammad Mahmoud A,
Sunehag Agneta L,
Haymond Morey W
Publication year - 2009
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.23.1_supplement.546.11
Subject(s) - lipogenesis , glycerol , medicine , lactation , endocrinology , meal , chemistry , crossover study , de novo synthesis , biology , biochemistry , metabolism , pregnancy , placebo , genetics , alternative medicine , pathology , enzyme
Background Milk fat is composed of 98% triglycerides (TG) and provides infants with ~50 % of their calories. Mammary gland de novo lipogenesis contributes significantly to milk fat in animals. However, there are no data regarding this process in humans. Hypotheses Incorporation of 13 C carbons from [U‐ 13 C]glucose into fatty acids (FAs) and glycerol in TG will be, higher in milk TG than in plasma, and higher during H‐CHO than H‐F diet. Subjects 7 healthy lactating women were studied in a crossover, randomized design during isocaloric, isonitrogenous, H‐F (30%CHO, 55%fat) and H‐CHO (60%CHO, 25%fat) diets. Following feeding for 7 days on each diet, women were continuously infused with [U‐ 13 C]glucose for 5h following a 12h fast and during 7h of feeding. Incorporation of 13 C from [U‐ 13 C]glucose into FAs and glycerol was measured in both plasma and milk using GC‐MS. Results Incorporation of 13 C from [U‐ 13 C]glucose into milk FAs increased (p<0.05) with the increased chain length of the FAs from C2 to C12 then, declined in C14 and was not detected in FAs longer than C16. During meal absorption, enrichment of 13 C was ~3 fold higher in milk FA and ~7 fold higher in milk glycerol compared to plasma FAs and glycerol. During fasting, 25% and 6% of medium chain FAs (MCFAs) (C6‐C12) were derived from glucose following H‐CHO and H‐F diets, respectively. However, during feeding, de novo lipogenesis from glucose was 60% and 20% of MCFAs during both H‐CHO and H‐F diet, respectively. Conclusions The human mammary gland is capable of de novo lipogenesis, mainly MCFAs, which is increased during a H‐CHO diet. RO1DK 55478, HD 37857, MO1‐RR‐00188‐34.