Shogo Igarashi

The presence of collagenase in Kupffer cells of the rat liver

Abstract Collagenase was first demonstrated as an active form in the Kupffer cells of the rat liver. The cells were isolated by the method of protease digestion and bovine serum albumin floatation. The activity was approximately three to five times higher than that of the rat granulocytes.

Demonstration of collagenase activity in rat liver homogenate.

Abstract Collagenase activity became detectable in rat liver homogenate by washing liver tissue repeatedly with buffered saline before homogenization. This enzyme activity was inhibited by adding minute quantities of serum. These data suggest that collagenase is active in situ in the liver, but is made inactive during the homogenization by forming a complex with contaminating serum factors.

Collagenase-like peptidase activity in fibrotic liver tissue

Abstract Activities of an enzyme capable of digesting carbobenzoxy-glycyl-prolyl-leucyl-glycyl-proline proved to be significantly elevated in fibrotic and cirrhotic human liver tissues, as well as in experimentally induced fibrotic rat liver tissues. Hydroxyproline content was also elevated.

Effect of synthetic tripeptides on cell proliferation and protein biosynthesis of 3T6 cells and isolated rat hepatocytes

四つの合成tripeptide, lysyl-cysteinyl-histidine, histidyl-Phenylalanyl-lysine, lysyl-cy-steinyl-glycineおよびlysyl-tyrosyl-glycineの細胞増殖ならびに蛋白合成にたいする効果を,線維芽細胞(3T6 cell)とラットの遊離肝細胞の培養により検討した.1) 3T6細胞をDulbecco-Vogtのメジウム中で3H-proline 2μc, tripeptide 10μgを加え,コラーゲンの生合成を3H-hydroxyprolineを指標としてみると,メジウム中細胞内ともにtripeptideの投与により,その比放射能の増加が認められた.12時間の培養で細胞数の変化は認められなかった.2) コラゲナーゼの直接注入法により遊離させたラットの肝細胞を10%牛胎児血清を含むEagleのMEMで培養,tripeptide 10μg, 14C-leucine 1μcを加えて12時間後に細胞を集め,蛋白量,蛋白への14C-leucineのとりこみをみると,tripeptideの投与により蛋白量,比放射能ともに増加がみられたが細胞内の糖含量には変化が認められなかった.また細胞数にも著しい増加はみられなかった.3) 四つの合成tripeptideの中,蛋白合成にたいする効果は,lysyl-cysteinyl-histidineおよびhistidyl-phenylalanyl-lysineで他の二つよりも強いように思われた.tripeptideの蛋白合成にたいする効果の作用機序は詳かでないが,peptide中のpolar amino acid, aliphatic amino acidが何らかの関係を有するものと思われる.

Biochemical Analysis of The Collagen from Cirrhotic Human Liver

ヒトの乙型硬変肝のコラーゲンを1M食塩(中性溶性コラーゲン),および0.5M酢酸(酸溶性コラーゲン)で抽出し,そのアミノ酸組成,糖含量および分子量を測定した.1) ヒトの硬変肝から抽出されたコラーゲンもカルボキシメチルセルロースクロマトグラフィーによりα1,α2およびβ12鎖に分離出来る.2) α1,α2鎖のアミノ酸組成は,ハイドロオキシプロリン,メチオニンが少なく,ハイドロオキシリジン,ヒスチジンが多い.α2鎖により多く塩基性アミノ酸が含まれている.3) α1,α2,β12鎖ともに糖含量が著しく多く,糖を介する基質との結合が,ヒトの硬変肝のコラーゲンの抽出を困難にしているものと考えられる.4) α1,α2鎖の分子量は103,000, 106,000と推定される.

Effect of 3,5,3’triiodothyropropionic acid on fibrotic rat liver

ConclusionThyroxine derivative, 3,5,3′-triiodothyropropionic acid, has some effect on collagen degradation and showed an inhibitory effect on development of rat liver fibrosis induced by swine serum injection.