葉酸投与による腎の肥大について

Abstract

Hyperplasia of rat kidneys induced by a single intraperitoneal injection of folic acid (250 mg per kg of body weight) was investigated by measuring the amount of Feulgen-DNA in renal cell nuclei and the mitotic rate. 1) Wet weight of the rat kidneys increased rapidly after folic acid injection. At 6 hours, there was a mean increase of 25%, rising to a maximum of 80% at 12 hours and declining to 16% at 4 days. 2) Then the kidney was halved along the long axis a strongly yellow stained band corresponding closely to the inner stripe of the outer medulla was seen across the exposed surface from 2 to 18 hours after folic acid injection. The lumens of the distal tubules were filled with folate crystals only 30 min. after injection and were almost free of folate deposits at 48 hours. At 48 hours after injection, the proximal and distal tubules were dilated but no collapsed tubules could be detected. 3) At 2 days after folate injection, the maximum increase of Feulgen-DNA content in the renal cell nuclei was observed, with a return to normal value within 3 days. 4) It was shown that the mitotic rate reached a maximum at 2-4 days after folate injection, declining nearly to the control value at 6 days. 5) The changing pattern of Feulgcn-DNA content in folate stimulated renal cell nuclei correlated well with that of mitotic activity.