Acetyl-Coenzyme A Carboxylase Messenger Ribonucleic Acid Metabolism in Liver, Adipose Tissues, and Mammary Glands During Pregnancy and Lactation

Abstract

In the rat, the acetyl-coenzyme A carboxylase gene exists as a single copy per haploid chromosome set. However, multiple forms of acetyl-coenzyme A carboxylase mRNA exist, the relative abundance of which varies in a tissue-specific manner under different physiological conditions. In the mammary gland, the major acetyl-coenzyme A carboxylase mRNA species are of the class 2 type, which are products of promoter II. In parametrial white adipose tissue, the main form of species of acetyl-coenzyme A carboxylase is of the class 1 type, which are produced by promoter I. Pregnancy and lactation affect the amounts of these acetyl-coenzyme A carboxylase mRNA. Although the mammary gland acetyl-coenzyme A carboxylase mRNA species increase dramatically upon parturition, the parametrial white adipose tissue forms decrease precipitously at the same time and are not expressed at all during the lactation period. In the liver of these animals, the only form of acetyl-coenzyme A carboxylase mRNA that is expressed is the FL56 form; this form shows a modest decrease during pregnancy that is slowly reversed during lactation. These observations indicate that the changes in lipogenesis that occur during pregnancy and lactation are determined by the transcriptional activity of the acetyl-coenzyme A carboxylase gene. In order to analyze the complex transcriptional activity of this gene in a meaningful way, it is necessary to examine the metabolism of individual isoforms of acetyl-coenzyme A carboxylase mRNA.

Expression and nutritional regulation of lipogenic genes in mammary gland and adipose tissues of lactating goats

“…Similarly, LPL, FAS and G6PDH activities (Table 3) were higher in lactating mammary gland than in AT. These results are consistent with specific physiological adaptations of the metabolism of the mammary gland and other tissues, including AT, which occur during lactation in cows and in rats (Ponce-Castañ eda et al 1991), with a decrease in FA uptake and fat synthesis de novo in AT and an increase in lipogenic activity in the mammary gland. Similarly, in lactating sheep, Vernon et al (1987) demonstrated that G6PDH and ACC activities were higher in mammary gland than in subcutaneous and perirenal AT.…”

Expression and nutritional regulation of lipogenic genes in mammary gland and adipose tissues of lactating goats

“…Similarly, LPL, FAS and G6PDH activities (Table 3) were higher in lactating mammary gland than in AT. These results are consistent with specific physiological adaptations of the metabolism of the mammary gland and other tissues, including AT, which occur during lactation in cows and in rats (Ponce-Castañ eda et al 1991), with a decrease in FA uptake and fat synthesis de novo in AT and an increase in lipogenic activity in the mammary gland. Similarly, in lactating sheep, Vernon et al (1987) demonstrated that G6PDH and ACC activities were higher in mammary gland than in subcutaneous and perirenal AT.…”

Metabolism and lactation performance in dairy cows fed a diet containing rumen-protected fat during the last twelve weeks of gestation

“…However, because the activity of ACCα-P2 is also reduced, it is clear that the metabolic reprogramming peripartum reduces the activity of both ACCα promoters in adipose tissue of the cow. These findings are in line with previous reports from rats and cows that ACCα mRNA abundance in adipose tissue decreases dramatically from pre-to postpartum (Ponce-Castaneda et al, 1991;Doepel et al, 2002;Sumner et al, 2008), indicating that FA synthesis in s.c. fat is shut off immediately at parturition irrespective of dietary nutrient composition. It is known from cattle that the major site for FA synthesis is adipose tissue, and not liver.…”

Genomic distribution of three promoters of the bovine gene encoding acetyl-CoA carboxylase α and evidence that the nutritionally regulated promoter I contains a repressive element different from that in rat

“…The observed heterogeneity of the 5h UTR regions of the bovine ACC-α mRNA conforms well to that what is known from rat and human [17,18]. However, neither has a splice variant of exon 3 been reported previously, nor has a class 2 message been found of the composition (2 : 3 : 5).…”

“…Our amplifications show that their concentration does not increase during lactation, although the total concentration of the ACC-α mRNA increases during lactation in this tissue (Figure 2) [13,14,21]. PI might not be the promoter driving the lactationally stimulated expression of the ACC-α encoding gene in mammary epithelial cells, either in cattle (this study) or in rat [17]. Rather, PIII is the lactationally stimulated bovine ACC-α promoter, as has previously been reported from sheep [20].…”

Expression and nutritional regulation of lipogenic genes in mammary gland and adipose tissues of lactating goats

“…Similarly, LPL, FAS and G6PDH activities (Table 3) were higher in lactating mammary gland than in AT. These results are consistent with specific physiological adaptations of the metabolism of the mammary gland and other tissues, including AT, which occur during lactation in cows and in rats (Ponce-Castañ eda et al 1991), with a decrease in FA uptake and fat synthesis de novo in AT and an increase in lipogenic activity in the mammary gland. Similarly, in lactating sheep, Vernon et al (1987) demonstrated that G6PDH and ACC activities were higher in mammary gland than in subcutaneous and perirenal AT.…”

Metabolism and lactation performance in dairy cows fed a diet containing rumen-protected fat during the last twelve weeks of gestation

“…However, because the activity of ACCα-P2 is also reduced, it is clear that the metabolic reprogramming peripartum reduces the activity of both ACCα promoters in adipose tissue of the cow. These findings are in line with previous reports from rats and cows that ACCα mRNA abundance in adipose tissue decreases dramatically from pre-to postpartum (Ponce-Castaneda et al, 1991;Doepel et al, 2002;Sumner et al, 2008), indicating that FA synthesis in s.c. fat is shut off immediately at parturition irrespective of dietary nutrient composition. It is known from cattle that the major site for FA synthesis is adipose tissue, and not liver.…”

Genomic distribution of three promoters of the bovine gene encoding acetyl-CoA carboxylase α and evidence that the nutritionally regulated promoter I contains a repressive element different from that in rat

“…The observed heterogeneity of the 5h UTR regions of the bovine ACC-α mRNA conforms well to that what is known from rat and human [17,18]. However, neither has a splice variant of exon 3 been reported previously, nor has a class 2 message been found of the composition (2 : 3 : 5).…”

“…Our amplifications show that their concentration does not increase during lactation, although the total concentration of the ACC-α mRNA increases during lactation in this tissue (Figure 2) [13,14,21]. PI might not be the promoter driving the lactationally stimulated expression of the ACC-α encoding gene in mammary epithelial cells, either in cattle (this study) or in rat [17]. Rather, PIII is the lactationally stimulated bovine ACC-α promoter, as has previously been reported from sheep [20].…”

Expression and nutritional regulation of lipogenic genes in mammary gland and adipose tissues of lactating goats

“…Similarly, LPL, FAS and G6PDH activities (Table 3) were higher in lactating mammary gland than in AT. These results are consistent with specific physiological adaptations of the metabolism of the mammary gland and other tissues, including AT, which occur during lactation in cows and in rats (Ponce-Castañ eda et al 1991), with a decrease in FA uptake and fat synthesis de novo in AT and an increase in lipogenic activity in the mammary gland. Similarly, in lactating sheep, Vernon et al (1987) demonstrated that G6PDH and ACC activities were higher in mammary gland than in subcutaneous and perirenal AT.…”

Metabolism and lactation performance in dairy cows fed a diet containing rumen-protected fat during the last twelve weeks of gestation

“…However, because the activity of ACCα-P2 is also reduced, it is clear that the metabolic reprogramming peripartum reduces the activity of both ACCα promoters in adipose tissue of the cow. These findings are in line with previous reports from rats and cows that ACCα mRNA abundance in adipose tissue decreases dramatically from pre-to postpartum (Ponce-Castaneda et al, 1991;Doepel et al, 2002;Sumner et al, 2008), indicating that FA synthesis in s.c. fat is shut off immediately at parturition irrespective of dietary nutrient composition. It is known from cattle that the major site for FA synthesis is adipose tissue, and not liver.…”

Genomic distribution of three promoters of the bovine gene encoding acetyl-CoA carboxylase α and evidence that the nutritionally regulated promoter I contains a repressive element different from that in rat

“…The observed heterogeneity of the 5h UTR regions of the bovine ACC-α mRNA conforms well to that what is known from rat and human [17,18]. However, neither has a splice variant of exon 3 been reported previously, nor has a class 2 message been found of the composition (2 : 3 : 5).…”

“…Our amplifications show that their concentration does not increase during lactation, although the total concentration of the ACC-α mRNA increases during lactation in this tissue (Figure 2) [13,14,21]. PI might not be the promoter driving the lactationally stimulated expression of the ACC-α encoding gene in mammary epithelial cells, either in cattle (this study) or in rat [17]. Rather, PIII is the lactationally stimulated bovine ACC-α promoter, as has previously been reported from sheep [20].…”