A transmission electron microscopic study of rabbit liver sinusoids with special remarks on an experimentally induced canalicular system and the "pored domes" in the endothelial cells.

Rabbits were starved for a week and then allowed to take the standard diet; the animals were sacrificed after 20 or 24 hr. One group of the animals were treated in winter, and the other, in summer. Control animals were fed solid rabbit food ad libitum. In the control rabbits, short rudimentary canaliculi and occasional small-sized pored domes were found in the thicker portions of the endothelial extension. In the animals experimentally treated in winter, well-developed meandering canaliculi with vacuolar expansions and constrictions appeared in the thicker portions and perikaryonal cytoplasm. In addition prominent pored domes were produced. The canaliculi often formed sponge-like networks with openings both to the sinusoid and the Disse's space. The development of the canalicular system and pored domes correlated to an increased blood flow through the sinusoids; this seemed to be induced upon sudden feedings after lengthy starvation. The rabbits subjected to the experimental treatment in summer exhibited no distinct development of the canaliculi and pored domes. This result was ascribed to the inhibited functions of the rabbit liver during this season.