Intrahepatic distribution of hepatic arterial and portal venous flows in the dog

Jn, Cohn; Pinkerson, AL

doi:10.1152/ajplegacy.1969.216.2.285

Cited by 23 publications

(8 citation statements)

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“…It might have been more desirable to determine portal and hepatic arterial flow separately. Whether distribution of hepatic arterial and portal venous flow through the hepatic lobule differs is not certain (29)(30)(31), so estimates of transport of metabolites based upon any measure of distribution of flow between portal vein and hepatic artery may be subject to an error for which there is no obvious remedy. For all the substances studied here (excepting extrahepatic production of FFA) contribution of the liver to uptake or production considerably exceeded that of the extrahepatic splanchnic region.…”

Section: Discussionmentioning

confidence: 99%

Hepatic metabolism of free fatty acids in normal and diabetic dogs

Basso¹,

Havel²

1970

J. Clin. Invest.

204

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A B S T R A C T Fasted dogs prepared with catheters in the femoral artery, portal vein, and hepatic vein and infused intravenously with palmitate-1-m4C were used to estimate uptake of free fatty acids in liver and their conversion to major metabolic products secreted into hepatic venous blood. Animals were studied under ordinary conditions and when fat mobilization was increased abruptly by infusing norepinephrine or for a prolonged period by withdrawing insulin from depancreatized dogs. 80% of hepatic blood flow was assumed to be derived from the portal vein.Hepatic uptake was proportional to net outflow transport of plasma free fatty acids in the three groups and, in each, hepatic extraction fraction was about 25%. Since specific activity of free fatty acids entering and leaving the liver was equal and their composition was closely similar in the three sites sampled, it was concluded that palmitate is a representative tracer for free fatty acids entering the liver and that the liver does not release free fatty acids into the blood.In norepinephrine-infused dogs, the fraction of free fatty acids secreted in triglycerides (13%) was similar to that of control animals, so that transport of triglycerides was increased. In diabetic dogs no increased transport could be demonstrated since an average of only 2% of free fatty acids was converted to plasma triglyceride fatty acids; the hyperlipemia uniformly observed therefore appeared to result from defective removal of triglycerides from the blood.A similar fraction of free fatty acids was converted to ketones in normal and norepinephrine-infused dogs. This fraction was somewhat higher in diabetic animals and, in addition, a substantial quantity of ketones was

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Section: Discussionmentioning

confidence: 99%

Hepatic metabolism of free fatty acids in normal and diabetic dogs

Basso¹,

Havel²

1970

J. Clin. Invest.

204

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“…38 A few studies with isotope clearance or indicator-dilution technique have reported unusual measurements suggesting the presence of functionally separate capillary beds for hepatic artery and portal vein, 9,39,40 and the regular bypass of arterial flow over hepatic parenchyma. 23,41,42 These interpretations have received little attention so far, because support from an anatomic entity had been lacking. Secondly, it strongly suggests that all tunics of hepatic veins do not receive sufficient oxygenation from luminal venous blood, but have to depend on the vasa vasorum, or more specifically vasa venarum, delivering fresh arterial blood to meet local metabolic needs.…”

Section: Morphological Considerationsmentioning

confidence: 99%

The isolated artery: An intrahepatic arterial pathway that can bypass the lobular parenchyma in mammalian livers

Ekataksin

2000

Hepatology

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Controversy persists concerning the distribution of intrahepatic arterial termination. Apart from nourishing structures in the portal tract, several authors have suggested arterial supply to some isolated vascular beds that bypass the parenchyma, but this was not verified morphologically. In the present study, the existence of an isolated hepatic artery unaccompanied by a portal vein or a bile duct was shown in livers of pigs and other mammals including the dog, seal, ox, horse, and man. After colored media injection, liver blocks were sampled near the hepatic capsule and hepatic vein and subject to histologic assessment. The hepatic artery dissociated from superficial portal tract, ramified, and anastomosed extensively, forming a capsular plexus that drained at places into peripheral sinusoids in which resistive structural elaborations were observed. The artery also dissociated and fed an intramural plexus (vasa vasorum) of hepatic veins. This was collected into a vessel that penetrated the intima into the vein's lumen. In smaller sublobular veins, the plexus emptied into adjacent sinusoids; in central veins, the plexus was poorly developed. In canine and phocine livers, which have a special throttling musculature in sublobular veins, the isolated arterioles were numerous; in bovine and equine livers, which have a thick fibrous investment, the capsular plexus was welldeveloped. Occurrence of the isolated artery also was confirmed in the human but not in the rodent liver. In conclusion, the isolated artery is responsible for isolated vascular beds, in which the transintimal pathway can bypass the lobular sinusoids. (HEPATOLOGY 2000;31:269-279.)There is no definite consensus concerning the distribution and functions of the hepatic artery. Intrahepatic termination of the arteria hepatica propria has been a controversial issue for more than a century. 1 Review of the literature shows that the subject became controversial in 1866, when Chrzonszczewsky, 2 with his classic experiments of selective ligation and injection, observed that branches of the hepatic artery penetrated into the depth of the lobule, and concluded subsequently that the artery nourished the central half of the liver lobule, whereas the portal vein supplied the peripheral half. One hundred years later, in 1966, not only were the statements unsupported, but also many studies extended the controversy about the anatomy 3-7 and physiology 8,9 of intrahepatic arterial distribution. As a result, the clinical and pathological significance of the hepatic artery has remained ill defined, because how the vessel ramifies in the liver has not been accurately described. 10 Microscopic terminations of the hepatic artery are classified into 2 categories, within the portal tract and outside of the portal tract. The former is associated with the formation of periductal plexus and arterioportal anastomosis, 11 whereas the latter is typically related to the distribution of intralobular arterioles. 12 It is the second category that has been most argued. From time to t...

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“…Field & Andrews, 1968;Cohn & Pinkerson, 1969). Accordingly the 'input' cortisol concentrations were taken to be those of a mixture of 0-2 vol arterial plasma and 0-8 vol portal venous plasma.…”

Section: Dissociation Of Transcortin-bound Cortisol At 22°cmentioning

confidence: 99%

The Rate Constants for the Interaction of Cortisol and Transcortin, and the Rate of Dissociation of Transcortin-Bound Cortisol in the Liver

Paterson¹

1973

Journal of Endocrinology

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The apparent rate of dissociation of transcortin-bound cortisol in human plasma was measured. After establishing equilibrium between plasma proteins and endogenous and added [3H]cortisol, this was perturbed by addition of a known amount of exogenous cortisol. Plasma protein-bound [3H]cortisol was then measured by gel filtration at timed intervals. This system can be described by six differential equations, one each for unbound, albumin-bound and transcortin-bound cortisol and [3H]cortisol.The rate constants for the transcortin\p=m-\cortisolreaction were estimated by numerical solution of these equations, using arbitrary rate constants for the albumin\p=m-\steroidreaction.At 2 \ s=deg\ Cthe dissociation of transcortin-bound cortisol has a rate constant of 0\m=.\00041s\ m=-\1, at 10 \ s=deg\ C0\m=.\00179s\ m=-\1 and at 22 \ s=deg\ C0\m=.\0353s\m=-\1. At 37 \ s=deg\ Cthe reaction was very rapid and equilibrium appeared to be attained in less than 5 s. The rate constant could only be estimated by using the Arrhenius equation, In (k) = const+E/RT, and was found to be 0\m=.\633s\m=-\1.The rate constants for cortisol\p=m-\plasmaprotein interaction were applied to a differential equation model for the splanchnic uptake of cortisol. Using experimental measurements of the visceral and hepatic uptake of cortisol in sheep the rate constant for the visceral removal of cortisol was found to be 0\m=.\0299\ m=+-\ 0\m=.\0065 (s.e.m.) s\m=-\1 and the hepatic constant was 0\m=.\4674\ m=+-\0\m=.\0540 (s.e.m.) s\m=-\1. In normal conscious sheep the total splanchnic uptake of cortisol appeared to be derived 42% from unbound, 31% from albuminbound and 27 % from transcortin-bound steroid.

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Intrahepatic distribution of hepatic arterial and portal venous flows in the dog

Cited by 23 publications

References 0 publications

Hepatic metabolism of free fatty acids in normal and diabetic dogs

Hepatic metabolism of free fatty acids in normal and diabetic dogs

The isolated artery: An intrahepatic arterial pathway that can bypass the lobular parenchyma in mammalian livers

The Rate Constants for the Interaction of Cortisol and Transcortin, and the Rate of Dissociation of Transcortin-Bound Cortisol in the Liver

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