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Serotonin (5-HT) affects expression of liver metabolic enzymes and mammary gland glucose transporters during the transition from pregnancy to lactation.

Laporta J, Peters TL, Merriman KE, Vezina CM, Hernandez LL - PLoS ONE (2013)

Bottom Line: The aim of this experiment was to demonstrate the ability of feeding serotonin (5-HT; 5-hydroxytryptamine) precursors to increase 5-HT production during the transition from pregnancy to lactation and the effects this has on maternal energy metabolism in the liver and mammary gland.Feeding 5-HTP resulted in increased mRNA expression of key gluconeogenic and glycolytic enzymes in liver and glucose transporters 1 and 8 (GLUT-1, -8) in the mammary gland.Our results suggest that increasing 5-HT production during the transition from pregnancy to lactation increases mRNA expression of enzymes involved in energy metabolism in the liver, and mRNA abundance and distribution of glucose transporters within the mammary gland.

View Article: PubMed Central - PubMed

Affiliation: Department of Dairy Science, University of Wisconsin-Madison, Madison, Wisconsin, United States of America.

ABSTRACT
The aim of this experiment was to demonstrate the ability of feeding serotonin (5-HT; 5-hydroxytryptamine) precursors to increase 5-HT production during the transition from pregnancy to lactation and the effects this has on maternal energy metabolism in the liver and mammary gland. Pregnant rats (n = 45) were fed one of three diets: I) control (CON), II) CON supplemented with 0.2% 5-hydroxytryptophan (5-HTP) or III) CON supplemented with 1.35% L-tryptophan (L-TRP), beginning on d13 of pregnancy through d9 of lactation (d9). Serum (pre and post-partum), milk (daily), liver and mammary gland tissue (d9) were collected. Serum 5-HT was increased in the 5-HTP fed dams beginning on d20 of gestation and remained elevated through d9, while it was only increased on d9 in the L-TRP fed dams. 5-HT levels were increased in mammary gland and liver of both groups. Additionally, 5-HTP fed dams had serum and milk glucose levels similar to the CON, while L-TRP had decreased serum (d9) and milk glucose (all dates evaluated). Feeding 5-HTP resulted in increased mRNA expression of key gluconeogenic and glycolytic enzymes in liver and glucose transporters 1 and 8 (GLUT-1, -8) in the mammary gland. We demonstrated the location of GLUT-8 in the mammary gland both in the epithelial and vascular endothelial cells. Finally, phosphorylated 5' AMP-activated protein kinase (pAMPK), a known regulator of intracellular energy status, was elevated in mammary glands of 5-HTP fed dams. Our results suggest that increasing 5-HT production during the transition from pregnancy to lactation increases mRNA expression of enzymes involved in energy metabolism in the liver, and mRNA abundance and distribution of glucose transporters within the mammary gland. This suggests the possibility that 5-HT may be involved in regulating energy metabolism during the transition from pregnancy to lactation.

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Liver mRNA expression of gluconeogenic and glycolytic enzymes.Liver mRNA expression of dams on d9 of lactation of pyruvate carboxylase (PC), phosphoenolpyruvate carboxykinase-1 (PCK1), pyruvate dehydrogenase kinase, isozyme 4 (PDK4), and phosphofructokinase-1 (PFK1) in dams fed CON, 5-HTP, and L-TRP diets. Data are represented as mean ± SEM. Single asterisk (*) indicate statistical significance at P<0.05, two asterisks (**) at P<0.01, three (***) at P<0.001.
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pone-0057847-g003: Liver mRNA expression of gluconeogenic and glycolytic enzymes.Liver mRNA expression of dams on d9 of lactation of pyruvate carboxylase (PC), phosphoenolpyruvate carboxykinase-1 (PCK1), pyruvate dehydrogenase kinase, isozyme 4 (PDK4), and phosphofructokinase-1 (PFK1) in dams fed CON, 5-HTP, and L-TRP diets. Data are represented as mean ± SEM. Single asterisk (*) indicate statistical significance at P<0.05, two asterisks (**) at P<0.01, three (***) at P<0.001.

Mentions: Hepatic regulation of energy metabolism is critical for the support of glucose homeostasis during times of low energy supply, as seen during the transition from pregnancy to lactation [27]. Liver mRNA expression of key enzymes involved in energy metabolism was evaluated in this study. Maternal liver mRNA expression of pyruvate carboxylase (PC) was increased only in the dams consuming the 5-HTP diet (P = 0.0087, Figure 3), and phosphoenolpyruvate carboxykinase 1 (PCK1) tended to increase in those animals as well (P = 0.09, Figure 3). Liver mRNA expression of pyruvate dehydrogenase kinase, isozyme 4 (PDK4) was increased in animals consuming both the L-TRP and 5-HTP diets, but more significantly in 5-HTP fed dams (P<0.041, Figure 3). mRNA expression of PFK1 was only increased in the L-TRP group compared to CON (P = 0.001, Figure 3).


Serotonin (5-HT) affects expression of liver metabolic enzymes and mammary gland glucose transporters during the transition from pregnancy to lactation.

Laporta J, Peters TL, Merriman KE, Vezina CM, Hernandez LL - PLoS ONE (2013)

Liver mRNA expression of gluconeogenic and glycolytic enzymes.Liver mRNA expression of dams on d9 of lactation of pyruvate carboxylase (PC), phosphoenolpyruvate carboxykinase-1 (PCK1), pyruvate dehydrogenase kinase, isozyme 4 (PDK4), and phosphofructokinase-1 (PFK1) in dams fed CON, 5-HTP, and L-TRP diets. Data are represented as mean ± SEM. Single asterisk (*) indicate statistical significance at P<0.05, two asterisks (**) at P<0.01, three (***) at P<0.001.
© Copyright Policy
Related In: Results  -  Collection

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getmorefigures.php?uid=PMC3585179&req=5

pone-0057847-g003: Liver mRNA expression of gluconeogenic and glycolytic enzymes.Liver mRNA expression of dams on d9 of lactation of pyruvate carboxylase (PC), phosphoenolpyruvate carboxykinase-1 (PCK1), pyruvate dehydrogenase kinase, isozyme 4 (PDK4), and phosphofructokinase-1 (PFK1) in dams fed CON, 5-HTP, and L-TRP diets. Data are represented as mean ± SEM. Single asterisk (*) indicate statistical significance at P<0.05, two asterisks (**) at P<0.01, three (***) at P<0.001.
Mentions: Hepatic regulation of energy metabolism is critical for the support of glucose homeostasis during times of low energy supply, as seen during the transition from pregnancy to lactation [27]. Liver mRNA expression of key enzymes involved in energy metabolism was evaluated in this study. Maternal liver mRNA expression of pyruvate carboxylase (PC) was increased only in the dams consuming the 5-HTP diet (P = 0.0087, Figure 3), and phosphoenolpyruvate carboxykinase 1 (PCK1) tended to increase in those animals as well (P = 0.09, Figure 3). Liver mRNA expression of pyruvate dehydrogenase kinase, isozyme 4 (PDK4) was increased in animals consuming both the L-TRP and 5-HTP diets, but more significantly in 5-HTP fed dams (P<0.041, Figure 3). mRNA expression of PFK1 was only increased in the L-TRP group compared to CON (P = 0.001, Figure 3).

Bottom Line: The aim of this experiment was to demonstrate the ability of feeding serotonin (5-HT; 5-hydroxytryptamine) precursors to increase 5-HT production during the transition from pregnancy to lactation and the effects this has on maternal energy metabolism in the liver and mammary gland.Feeding 5-HTP resulted in increased mRNA expression of key gluconeogenic and glycolytic enzymes in liver and glucose transporters 1 and 8 (GLUT-1, -8) in the mammary gland.Our results suggest that increasing 5-HT production during the transition from pregnancy to lactation increases mRNA expression of enzymes involved in energy metabolism in the liver, and mRNA abundance and distribution of glucose transporters within the mammary gland.

View Article: PubMed Central - PubMed

Affiliation: Department of Dairy Science, University of Wisconsin-Madison, Madison, Wisconsin, United States of America.

ABSTRACT
The aim of this experiment was to demonstrate the ability of feeding serotonin (5-HT; 5-hydroxytryptamine) precursors to increase 5-HT production during the transition from pregnancy to lactation and the effects this has on maternal energy metabolism in the liver and mammary gland. Pregnant rats (n = 45) were fed one of three diets: I) control (CON), II) CON supplemented with 0.2% 5-hydroxytryptophan (5-HTP) or III) CON supplemented with 1.35% L-tryptophan (L-TRP), beginning on d13 of pregnancy through d9 of lactation (d9). Serum (pre and post-partum), milk (daily), liver and mammary gland tissue (d9) were collected. Serum 5-HT was increased in the 5-HTP fed dams beginning on d20 of gestation and remained elevated through d9, while it was only increased on d9 in the L-TRP fed dams. 5-HT levels were increased in mammary gland and liver of both groups. Additionally, 5-HTP fed dams had serum and milk glucose levels similar to the CON, while L-TRP had decreased serum (d9) and milk glucose (all dates evaluated). Feeding 5-HTP resulted in increased mRNA expression of key gluconeogenic and glycolytic enzymes in liver and glucose transporters 1 and 8 (GLUT-1, -8) in the mammary gland. We demonstrated the location of GLUT-8 in the mammary gland both in the epithelial and vascular endothelial cells. Finally, phosphorylated 5' AMP-activated protein kinase (pAMPK), a known regulator of intracellular energy status, was elevated in mammary glands of 5-HTP fed dams. Our results suggest that increasing 5-HT production during the transition from pregnancy to lactation increases mRNA expression of enzymes involved in energy metabolism in the liver, and mRNA abundance and distribution of glucose transporters within the mammary gland. This suggests the possibility that 5-HT may be involved in regulating energy metabolism during the transition from pregnancy to lactation.

Show MeSH
Related in: MedlinePlus