| Coordination of mammary metabolism and blood flow after refeeding in rats. | |
| | |
MedLine Citation:
|
PMID: 19307635 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
|
The production of milk is closely linked to nutritional state in many mammalian species, but the mechanisms by which changes in nutritional state are signaled to the mammary glands are poorly understood. Simultaneous measurements of mammary blood flow and glucose arterio-venous difference were made across the inguinal mammary glands of anesthetized, lactating rats. Blood flow to the mammary glands of previously fed rats was 0.48 mL/min per gram of mammary tissue. Glucose supply was 1.7 mumol/min per gram and 28% was extracted by the mammary glands. After food deprivation for 18 h, mammary blood flow decreased 48%, glucose arterio-venous difference decreased 72%, and hematocrit increased 7%, resulting in a 60% decrease in glucose supply and an 88% decrease in glucose uptake. After 1 h of refeeding, glucose supply had returned to a similar level to that of normally fed animals, but glucose uptake was 60% higher than in the normally fed state. Mammary glucose uptake was not closely linked to either blood flow or glucose supply, suggesting that substrate supply was not the primary determinant of mammary metabolism. Denervation experiments showed that the mammary metabolic response to altered nutritional state was also unlikely to be closely controlled by neural pathways. Severance of the cutaneous branch of the posterior division of the femoral nerve innervating the inguinal mammary glands did not reduce the high glucose uptake by mammary glands of either fed or refed rats, nor did denervation change the low glucose uptake by mammary glands of food-deprived rats. Denervation reduced blood flow in the associated mammary gland, however, indicating that neural pathways may play a role in supporting mammary blood flow when food is available. In in vitro experiments, the rate of glucose uptake was 35% lower in mammary acini from food-deprived rats than in fed rats 2.5 h after tissue removal, indicating some persistence of the food deprivation-induced suppression of mammary metabolism. Administration of insulin increased glucose uptake in acini from both fed and food-deprived rats, indicating that insulin may be involved in signaling the mammary gland of the restoration of nutrient supply when food-deprived rats are refed. The effects of administration of a gut extract in vivo and in vitro are discussed. |
| | |
Authors:
|
K W Stewart; G J S Cooper; S R Davis |
Related Documents
:
|
18805815 - Natural variation in plasticity of glucose homeostasis and food intake. 3534915 - Effect of intra-third ventricular administration of insulin on food intake after food d... 8920115 - Response of broilers to deprivation of food and water for 24 hours. 10231165 - Ethanol consumption by c57bl/6 mice: influence of gender and procedural variables. 6090985 - There are receptors for neurotensin in the caudate nucleus and posterior hypothalamus. 18943625 - Effect of germination initiation on competitive capacity of trichoderma atroviride p1 c... |
Publication Detail:
|
Type: Journal Article; Research Support, Non-U.S. Gov't |
Journal Detail:
|
Title: Journal of dairy science Volume: 92 ISSN: 1525-3198 ISO Abbreviation: J. Dairy Sci. Publication Date: 2009 Apr |
Date Detail:
|
Created Date: 2009-03-24 Completed Date: 2009-04-24 Revised Date: - |
Medline Journal Info:
|
Nlm Unique ID: 2985126R Medline TA: J Dairy Sci Country: United States |
Other Details:
|
Languages: eng Pagination: 1543-53 Citation Subset: IM |
Affiliation:
|
School of Science and Primary Industries, Waikato Institute of Technology, Hamilton, New Zealand. Kevin.Stewart@wintec.ac.nz |
Export Citation:
|
APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
|
Animals Blood Glucose / analysis Denervation / veterinary Eating / physiology* Female Glucose / metabolism Insulin / blood Lactation Mammary Glands, Animal / blood supply*, innervation, metabolism* Rats Rats, Sprague-Dawley Time Factors |
| Chemical | |
Reg. No./Substance:
|
0/Blood Glucose; 11061-68-0/Insulin; 50-99-7/Glucose |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
Previous Document: Effect of intrauterine infusion of ceftiofur on uterine health and fertility in dairy cows.
Next Document: Performance and metabolic and endocrine changes with emphasis on glucose metabolism in high-yielding...