Metabolism of arterial plasma estrogens by the splanchnic organs of the dog in vivo

Delwood C. Collins; Hugh D. Robinson; Carolyn M. Howard; John R. K. Preedy

doi:10.1172/JCI106451

Metabolism of arterial plasma estrogens by the splanchnic organs of the dog in vivo

Delwood C. Collins, Hugh D. Robinson, Carolyn M. Howard, and John R. K. Preedy

Published December 1, 1970 - More info

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Abstract

In order to study the splanchnic metabolism of blood-borne estrogens, a constant infusion of estrone-6,7-³H was made in a series of dogs, and arteriovenous (A-V) differences at equilibrium were determined for estrone-6,7-³H and for its products estradiol-17β, estrone sulfate, estrone glucosiduronate, and estradiol-17β glucosiduronate across the splanchnic bed (artery-hepatic vein), the small intestine (artery-superior mesenteric vein), and the spleen (artery-splenic vein). Per cent extractions (100 - [V/A] 100) were calculated. The plasma metabolic clearance rate (MCR) for estrone was measured. Principal findings were as follows: mean MCR was 731 liters/day per m², SEM 50. By comparison with estimated hepatic plasma flow and using the observed splanchnic extraction of estrone, 45-71% of estrone metabolism was calculated to be extrasplanchnic. The significant mean per cent extractions were as follows (SEM in parentheses): splanchnic bedestrone 85.9 (1.92), estradiol-17β 88.11 (3.36), estrone sulfate 27.9 (5.22), estrone glucosiduronate -48.5 (9.33), estradiol-17β glucosiduronate -33.3 (80.3); small intestine—estrone 45.3 (2.60), estradiol-17β 46.1 (12.9), estrone glucosiduronate - 30.8 (7.9); spleen—estrone 35 (3.8), estrone glucosiduronate 12 (3.7). These results lead to the following conclusions. Both estrone and estradiol-17β are nearly completely extracted in one passage through the splanchnic bed. There is net uptake of estrone sulfate and net production of estrone glucosiduronate and of estradiol-17β glucosiduronate by the splanchnic bed. There is net uptake of estrone and of estradiol-17β by the intestine, associated with substantial net production of estrone glucosiduronate. There is net uptake of estrone by the spleen and a small but significant net uptake of estrone glucosiduronate.