Abstract
Re-feeding 24-h-starved lactating rats resulted in a rapid (within 0.5 h) restoration of glucose uptake by the mammary gland and a slower (within 3 h) restoration of fatty acid synthesis. The rapid reactivation of glucose uptake (82% of fed value within 0.5 h of re-feeding) correlated with a rapid reactivation of 6-phosphofructo-1-kinase (6-PF-1-K) and glycolysis (as determined by a 97% decrease in the [fructose-6-phosphate]/[fructose-1,6-bisphosphate] ratio). This could not be fully explained by a fall (29%) in the tissue concentration of its allosteric inhibitor, citrate. The delayed reactivation of pyruvate dehydrogenase (PDH) correlated very closely with the delayed reactivation of fatty acid synthesis and explained the continued output of pyruvate and lactate within the first 0.5 h of re-feeding. PDH reactivation preceded the reactivation of acetyl-CoA carboxylase (ACC), which did not occur significantly until 1.5 h of re-feeding. ACC reactivation correlated with a decrease in the tissue concentration of citrate and a second late phase of 6-PF-1-K activation. It is clear that the important regulatory steps 6-PF-1-K, PDH and ACC, are reactivated asynchronously in the lactating mammary gland in response to re-feeding starved rats and that PDH is more important than ACC in the regulation of fatty acid synthesis.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 474-484 |
| Number of pages | 11 |
| Journal | Biochimica et Biophysica Acta - General Subjects |
| Volume | 1336 |
| Issue number | 3 |
| DOIs | |
| State | Published - Oct 20 1997 |
| Externally published | Yes |
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Keywords
- 6-Phosphofructo-1-kinase
- Acetyl-CoA carboxylase
- Fatty acid synthesis
- Glucose
- Lactating mammary gland
- Pyruvate dehydrogenase
ASJC Scopus subject areas
- Biophysics
- Biochemistry
- Molecular Biology
Cite this
The role of pyruvate dehydrogenase, phosphofructo-1-kinase and acetyl-CoA carboxylase in the regulation of fatty acid synthesis in the lactating rat mammary gland during the starved to re-fed transition. / Hagopian, Kevork; Munday, Michael R.
In: Biochimica et Biophysica Acta - General Subjects, Vol. 1336, No. 3, 20.10.1997, p. 474-484.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - The role of pyruvate dehydrogenase, phosphofructo-1-kinase and acetyl-CoA carboxylase in the regulation of fatty acid synthesis in the lactating rat mammary gland during the starved to re-fed transition
AU - Hagopian, Kevork
AU - Munday, Michael R.
PY - 1997/10/20
Y1 - 1997/10/20
N2 - Re-feeding 24-h-starved lactating rats resulted in a rapid (within 0.5 h) restoration of glucose uptake by the mammary gland and a slower (within 3 h) restoration of fatty acid synthesis. The rapid reactivation of glucose uptake (82% of fed value within 0.5 h of re-feeding) correlated with a rapid reactivation of 6-phosphofructo-1-kinase (6-PF-1-K) and glycolysis (as determined by a 97% decrease in the [fructose-6-phosphate]/[fructose-1,6-bisphosphate] ratio). This could not be fully explained by a fall (29%) in the tissue concentration of its allosteric inhibitor, citrate. The delayed reactivation of pyruvate dehydrogenase (PDH) correlated very closely with the delayed reactivation of fatty acid synthesis and explained the continued output of pyruvate and lactate within the first 0.5 h of re-feeding. PDH reactivation preceded the reactivation of acetyl-CoA carboxylase (ACC), which did not occur significantly until 1.5 h of re-feeding. ACC reactivation correlated with a decrease in the tissue concentration of citrate and a second late phase of 6-PF-1-K activation. It is clear that the important regulatory steps 6-PF-1-K, PDH and ACC, are reactivated asynchronously in the lactating mammary gland in response to re-feeding starved rats and that PDH is more important than ACC in the regulation of fatty acid synthesis.
AB - Re-feeding 24-h-starved lactating rats resulted in a rapid (within 0.5 h) restoration of glucose uptake by the mammary gland and a slower (within 3 h) restoration of fatty acid synthesis. The rapid reactivation of glucose uptake (82% of fed value within 0.5 h of re-feeding) correlated with a rapid reactivation of 6-phosphofructo-1-kinase (6-PF-1-K) and glycolysis (as determined by a 97% decrease in the [fructose-6-phosphate]/[fructose-1,6-bisphosphate] ratio). This could not be fully explained by a fall (29%) in the tissue concentration of its allosteric inhibitor, citrate. The delayed reactivation of pyruvate dehydrogenase (PDH) correlated very closely with the delayed reactivation of fatty acid synthesis and explained the continued output of pyruvate and lactate within the first 0.5 h of re-feeding. PDH reactivation preceded the reactivation of acetyl-CoA carboxylase (ACC), which did not occur significantly until 1.5 h of re-feeding. ACC reactivation correlated with a decrease in the tissue concentration of citrate and a second late phase of 6-PF-1-K activation. It is clear that the important regulatory steps 6-PF-1-K, PDH and ACC, are reactivated asynchronously in the lactating mammary gland in response to re-feeding starved rats and that PDH is more important than ACC in the regulation of fatty acid synthesis.
KW - 6-Phosphofructo-1-kinase
KW - Acetyl-CoA carboxylase
KW - Fatty acid synthesis
KW - Glucose
KW - Lactating mammary gland
KW - Pyruvate dehydrogenase
UR - http://www.scopus.com/inward/record.url?scp=0030665702&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0030665702&partnerID=8YFLogxK
U2 - 10.1016/S0304-4165(97)00061-5
DO - 10.1016/S0304-4165(97)00061-5
M3 - Article
C2 - 9367175
AN - SCOPUS:0030665702
VL - 1336
SP - 474
EP - 484
JO - Biochimica et Biophysica Acta - General Subjects
JF - Biochimica et Biophysica Acta - General Subjects
SN - 0304-4165
IS - 3
ER -