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Expression of phosphoenolpyruvate carboxykinase isoforms in the mammary gland of dairy goats is regulated by insulin status
Year:
2013
Source of publication :
Open Agriculture Journal
Authors :
Mabjeesh, Sameer Jermaya
;
.
Shamay, Avi
;
.
Volume :
7
Co-Authors:
Mabjeesh, S.J., Animal Science Department, The Hebrew University of Jerusalem, Israel
Argov-Argman, N., Animal Science Department, The Hebrew University of Jerusalem, Israel
Sabastian, C., Animal Science Department, The Hebrew University of Jerusalem, Israel
Mbogori, T., Animal Science Department, The Hebrew University of Jerusalem, Israel
Shamay, A., Animal Science Department, The Volcani Center, Agricultural Research Organization, Israel
Facilitators :
From page:
65
To page:
72
(
Total pages:
8
)
Abstract:
Phosphoenolpyruvate carboxykinase (PEPCK) isoforms (c, cytosolic; m, mitochondria) are expressed in the liver and mammary gland. PEPCK-c is a rate-controlling enzyme for gluconeogenesis and glyceroneogenesis; its activity is decreased by insulin. PEPCK-m expression is constitutive and functions to channel lactate toward gluconeogenesis. We hypothesized that the increase in milk protein but decrease in milk lactose and fat when a hyperinsulinemic-euglycemic clamp (HIEC) is applied to dairy goats is due to decreased expression of mammary PEPCK-c mRNA. Late lactation goats (n = 4; 150 ± 30 days in milk) were subjected to saline infusion and HIEC (104 μg insulin/h) for 4-day periods in a 2 × 2 crossover design. On day 4 of each period, a mammary biopsy (~1 g) was taken from an udder half to determine expression of PEPCK-m and PEPCK-c mRNA by real-time RT-PCR. Plasma insulin increased 3.5-fold (P< 0.002) due to the HIEC and euglycemia was maintained. The HIEC decreased (P< 0.0001) dry matter intake (28%) and milk yield (26%). While milk fat content was not affected, HIEC increased (P< 0.001) milk protein content (2.82% vs. 3.09%) but decreased (P< 0.001) milk lactose content (4.22% vs. 4.03%). Expression of PEPCK-m mRNA was 9-fold higher (P< 0.004) than that of PEPCK-c. The HIEC decreased (P< 0.03) PEPCK-c mRNA 7-fold but tended to increase (P< 0.236) PEPCK-m mRNA 1.3-fold. These results demonstrate that insulin regulates mRNA expression of mammary PEPCK isoforms, and this may underlie the changes in milk-component synthesis observed when a HIEC is applied. © Mabjeesh et al.
Note:
Related Files :
Goat
Insulin
Mammary gland
PEPCK
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More details
DOI :
10.2174/1874331520130722002
Article number:
Affiliations:
Database:
Scopus
Publication Type:
article
;
.
Language:
English
Editors' remarks:
ID:
24978
Last updated date:
02/03/2022 17:27
Creation date:
17/04/2018 00:11
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Scientific Publication
Expression of phosphoenolpyruvate carboxykinase isoforms in the mammary gland of dairy goats is regulated by insulin status
7
Mabjeesh, S.J., Animal Science Department, The Hebrew University of Jerusalem, Israel
Argov-Argman, N., Animal Science Department, The Hebrew University of Jerusalem, Israel
Sabastian, C., Animal Science Department, The Hebrew University of Jerusalem, Israel
Mbogori, T., Animal Science Department, The Hebrew University of Jerusalem, Israel
Shamay, A., Animal Science Department, The Volcani Center, Agricultural Research Organization, Israel
Expression of phosphoenolpyruvate carboxykinase isoforms in the mammary gland of dairy goats is regulated by insulin status
Phosphoenolpyruvate carboxykinase (PEPCK) isoforms (c, cytosolic; m, mitochondria) are expressed in the liver and mammary gland. PEPCK-c is a rate-controlling enzyme for gluconeogenesis and glyceroneogenesis; its activity is decreased by insulin. PEPCK-m expression is constitutive and functions to channel lactate toward gluconeogenesis. We hypothesized that the increase in milk protein but decrease in milk lactose and fat when a hyperinsulinemic-euglycemic clamp (HIEC) is applied to dairy goats is due to decreased expression of mammary PEPCK-c mRNA. Late lactation goats (n = 4; 150 ± 30 days in milk) were subjected to saline infusion and HIEC (104 μg insulin/h) for 4-day periods in a 2 × 2 crossover design. On day 4 of each period, a mammary biopsy (~1 g) was taken from an udder half to determine expression of PEPCK-m and PEPCK-c mRNA by real-time RT-PCR. Plasma insulin increased 3.5-fold (P< 0.002) due to the HIEC and euglycemia was maintained. The HIEC decreased (P< 0.0001) dry matter intake (28%) and milk yield (26%). While milk fat content was not affected, HIEC increased (P< 0.001) milk protein content (2.82% vs. 3.09%) but decreased (P< 0.001) milk lactose content (4.22% vs. 4.03%). Expression of PEPCK-m mRNA was 9-fold higher (P< 0.004) than that of PEPCK-c. The HIEC decreased (P< 0.03) PEPCK-c mRNA 7-fold but tended to increase (P< 0.236) PEPCK-m mRNA 1.3-fold. These results demonstrate that insulin regulates mRNA expression of mammary PEPCK isoforms, and this may underlie the changes in milk-component synthesis observed when a HIEC is applied. © Mabjeesh et al.
Scientific Publication
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