ASSESSMENT OF RATE OF O-2 RELEASE FROM SINGLE HEPATIC SINUSOIDS OF RATS

Characteristics of O-2 release from single hepatic sinusoids are descr ibed in relation to the sinusoidal O-2 inflow for the first time. Micr ospectroscopic measurement of the rate of O-2 release (RO(2)) from sin gle sinusoids to surrounding hepatocytes was carried out at the edge o f the liver of anesthetized rats. The oxyhemoglobin inflow ([HbO(2)] i nflow) into sinusoids, which is a product of sinusoidal blood flow rat e and inflowing oxyhemoglobin concentration ([HbO(2)]), was varied by exchange transfusion of blood with physiological saline. 1) RO(2) from single hepatic sinusoids of control rats was fairly constant [0.66 +/ - 0.14 (SD) nmol.cm(-2).s(-1), with 18 sinusoids of 9 fats] over a wid e range of [HbO(2)] inflow (50-200 fmol/s). 2) In the cases of mild an emia, [HbO(2)] inflow scarcely decreased but RO(2) increased, probably because of the increased metabolism of hepatocytes. 3) In the cases o f severe anemia, [HbO(2)] inflow decreased below 50 fmol/s and RO(2) d ecreased accordingly. 4) In all cases no difference was observed betwe en the RO(2) values obtained from periportal zone and those from peric entral zone. These results are discussed on the bases of the vascular structure and function of hepatic sinusoids and on the animal model of hemorrhagic shock.