Uptake Of Serum Albumin Research Articles

Reserpine in experimental cerebral edema

Focal areas of hemorrhagic necrosis were produced in the brains of anesthetized rhesus monkeys by freezing through the intact skull. Half of the animals were given reserpine beginning one hour after injury, and all animals were killed 24 hours after injury. The edema associated with the lesions was assessed by various methods. The animals receiving reserpine showed significantly less edema than controls as judged by water changes in the damaged hemisphere and significantly less hemorrhage in the lesion as determined from changes in tissue iron. This was not accompanied by a decrease in serum albumin uptake but the uptake of Evans blue was diminished. Body temperature and systemic blood pressure were decreased in the reserpine-treated animals.

Contraluminal serum albumin uptake in isolated perfused renal tubules.

Contraluminal serum albumin uptake in isolated perfused renal tubules.

Intestinal Uptake of Macromolecules: Effect of Oral Immunization

Animals were orally immunized with horseradish peroxidase and bovine serum albumin, and absorption of these antigens was studied. In comparison with controls, a consistent and significant decrease in peroxidase uptake was noted in both germ-free and conventional rats immunized with peroxidase; a similar decrease in serum albumin uptake was also noted in animals immunized with serum albumin. There was no difference in the uptake of an unrelated macromolecule. These observations suggest that local immunization interferes specifically with the intestinal uptake of macromolecular antigens.

Serum albumin uptake in isolated perfused renal tubules. Quantitative and electron microscope radioautographic studies in three anatomical segments of the rabbit nephron.

Proximal convoluted, proximal straight, and cortical collecting tubular segments isolated from rabbit kidney were perfused with I 125-labeled rabbit serum albumin (RSA-I 125) in ultrafiltrate of serum for up to 3 hr After perfusion, the segments were fixed with glutaraldehyde, embedded in Epon, and either counted with a gamma spectrometer to quantitate protein accumulation or analyzed by electron microscope radioautography to sequentially localize radioactivity Proximal convoluted and proximal straight segments accumulate RSA-I 125 nearly linearly as a function of time whereas cortical collecting segments do not accumulate measurable amounts of protein. The rate of accumulation of RSA-I 125 in the proximal convoluted tubule is 2 6 times as great as that in the proximal straight tubule. Electron microscope radioautography of the isolated proximal tubule demonstrated that RSA-I 125 is taken up via small apical vesicles and tubular invaginations, released into large cytoplasmic vacuoles, and finally concentrated in membrane-bounded structures, some of which are acid phosphatase positive These results show that albumin is absorbed by proximal tubules and may be degraded intracellularly within lysosomes. In addition, less radioactivity was located at all times over the lateral intercellular and basilar labyrinthine spaces, suggesting that labeled albumin and/or its breakdown products may be transported across the peritubular cell membrane.