HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Reynolds, C. K. Articles by Reynolds, P. J. Search for Related Content PubMed PubMed Citation Articles by Reynolds, C. K. Articles by Reynolds, P. J.

Net Metabolism of Hormones by Portal-Drained Viscera and Liver of Lactating Holstein Cows^1,2,

Department of Animal Science, University of Maryland, College Park 20742

Gerald B. Huntington, Theodore H. Elsasser, Henry F. Tyrrell and Paul J. Reynolds⁴

USDA, Agricultural Research Service, Livestock and Poultry Science Institute, Ruminant Nutrition Laboratory, Beltsville, MD 20705

ABSTRACT

Net flux of insulin, glucagon, somatotropin, somatomedin-C, and somatostatin across the portal-drained viscera and liver of four lactating Holstein cows was measured at 4 and 8 wk postpartum. Cows were fed for ad libitum intake a 60:40 corn silage:concentrate diet and milked at 12-h intervals. Milk yield and DM intake were 32.2 and 15.6 kg/d, respectively. Twenty-four consecutive measurements of insulin, glucagon, and somatotropin net flux were obtained at 30-min intervals; 12 hourly measurements were obtained for somatomedin-C and somatostatin. Net flux is venous-arterial concentration difference times blood flow. Net flux of somatomedin-C was not detectable across the portal-drained viscera or liver. Somatotropin was removed by total splanchnic tissues. There was net production of somatostatin across portal-drained viscera, but net flux of somatostatin across liver was not significant. On a net basis, removal of insulin and glucagon by liver accounted for 66% of portal-drained visceral production. Within cows and sampling days, increases in net portal-drained visceral production of insulin and glucagon often were mirrored by increases in net removal by liver. As in other species, the bovine liver is an important regulator of circulating concentrations of insulin and glucagon.

¹ Mention of a trade name, proprietary product, or specific equipment does not constitute a guarantee or warranty by the US Department of Agriculture and does not imply its approval to the exclusion of other products that may be suitable.

² Scientific Article Number A-4845, Contribution Number 7872 of the Maryland Agricultural Experiment Station, Department of Animal Sciences.

³ Present address: Ruminant Nutrition Laboratory, USDA, Agricultural Research Service, BARC-East, Beltsville, MD 20705.

⁴ Deceased.

This article has been cited by other articles:

				R. L. Baldwin VI, K. R. McLeod, J. P. McNamara, T. H. Elsasser, and R. G. Baumann Influence of abomasal carbohydrates on subcutaneous, omental, and mesenteric adipose lipogenic and lipolytic rates in growing beef steers J Anim Sci, September 1, 2007; 85(9): 2271 - 2282. [Abstract] [Full Text] [PDF]

				A. E. Relling and C. K. Reynolds Feeding Rumen-Inert Fats Differing in Their Degree of Saturation Decreases Intake and Increases Plasma Concentrations of Gut Peptides in Lactating Dairy Cows J Dairy Sci, March 1, 2007; 90(3): 1506 - 1515. [Abstract] [Full Text] [PDF]

				A. E. Relling and C. K. Reynolds Plasma Concentrations of Gut Peptides in Dairy Cattle Increase after Calving J Dairy Sci, January 1, 2007; 90(1): 325 - 330. [Abstract] [Full Text] [PDF]

				R. Berthiaume, M. C. Thivierge, R. A. Patton, P. Dubreuil, M. Stevenson, B. W. McBride, and H. Lapierre Effect of Ruminally Protected Methionine on Splanchnic Metabolism of Amino Acids in Lactating Dairy Cows J Dairy Sci, May 1, 2006; 89(5): 1621 - 1634. [Abstract] [Full Text] [PDF]