HCO 3 − -ATPase activity distribution in rat liver cell fractions prepared by zonal centrifugation

Summary Plasma membrane sheets prepared by zonal centrifugation of a premicrosomal pellet obtained from a rat liver homogenate are devoid of HCO ₃ ^– -ATPase activity. Since the microsomal fraction is also lacking in this ATPase activity, it can be concluded that the HCO ₃ ^– -ATPase is not involved in the secretion of HCO ₃ ^– into bile. Acknowledgments. This investigation was supported in part by grants No. DE-02600 and AM 80686 from the United States Public Health Service. The A-XII zonal rotor is used under subcontract No. 3796 with the Union Carbide Corporation.     

The distribution of bilirubin in rat liver fractions

Zusammenfassung Die Bilirubinmengen in den Geweben ikterischerGunn-Ratten werden zusammen mit den in den subzellulären Anterilen vorliegenden Bilirubinmengen ikterischerGunn-Rattenlebern bestimmt. Die Bilirubinbestimmung erfolgte nach i.v. Infusion von Bilirubin in die Rattenleber: es findet sich vorwiegend im Leberzellensaft der ikterischenGunn-Ratte, verteilt sich jedoch nach Bilirubininfusion gleichmässig über alle Leberanteile. Die teils bekannten, teils bestätigten Unterschiede können durch Plasma-Eiweiss-Bindung des Bilirubins erklärt werden.

---

---

We would like to thank Professor N. H.Martin for his advice and encouragement and the British Empire Cancer Campaign for financial assistance.     

Pantothenic acid distribution and protein synthesis in the particulate fractions of rat liver

Zusammenfassung Ratten wurden während 10 Wochen mit durch Pantothensäure angereicherte Nahrung oder mit Pantothensäure-Mangeldiät gefüttert. Im Anschluss daran wurden die durch Differentialzentrifugation gewonnenen Fraktionen von Leberhomogenat auf ihren Protein- und Panthothensäuregehalt untersucht. Die Resultate deuten darauf hin, dass Panthothensäure die Synthese von Leberproteinen, insbesondere in der Überstands-Fraktion, stimuliert.

---

---

Acknowledgement. Authors thank Dr. (Mrs.)A. Venkataraman and Dr.N. K. Dutta, Director of this Institute, for their encouragement and interest, and they are also grateful to Dr.M. J. Modak for his kind help.     

Enzymatic synthesis of trisialoganglioside by particulate fractions of rat liver

Summary Rat liver contains a particulate (membrane-bound) glycosyl transferase, concentrated in Golgi apparatus fractions, which catalyzes the synthesis of a trisialoganglioside from the ganglioside precursor disialohematoside (G_D3). Sialic acid was not incorporated into exogenous G_D1a from CMP-N-acetylneuraminic acid suggesting that G_D1a is an endproduct of the monosialoganglioside pathway. Thus, the disialoganglioside pathway may be a primary source of trisialoganglioside and higher ganglioside homologs in adult rat liver.     

Monoamine oxidase activity in membrane structures of rat liver cell

, .     

Evidence for enzymatic reduction of 1-nitropyrene by rat liver fractions

Summary 1-Nitropyrene, a mutagenic compound found in diesel exhaust and photocopy toners, is reduced anaerobically by rat liver fractions to 1-aminopyrene. This reaction is stimulated in the microsomal fraction by NADPH and in the cytosol by FMN. Addition of both cofactors produced more reduction in S-9, microsomes, or cytosol than either cofactor alone.     

Time course of the distribution of in vivo administered89Sr++ in rat liver subcellular fractions

Riassunto É stata studiata la distribuzione dello⁸⁹Sr⁺⁺ nelle frazioni subcellulari di fegato di ratto. Nei primi secondi dopo l'iniezione, la maggior parte dello⁸⁹Sr⁺⁺ si trova nei mitocondri. In alcuni minuti, la radioattività diminuisce nei mitocondri ed aumenta nel reticolo endoplasmico e nella fase solubile. Lo⁸⁹Sr⁺⁺ viene probabilmente trasferito da una struttura cellulare all'altra; i mitocondri ed il reticolo endoplasmico svolgono ruoli distinti nella deposizione dello Sr⁺⁺ nella cellula epatica.

---

---

This research was supported by the U.S. Public Health Service (Grant No. RO5 TW-00216) and by the Italian National Research Council, with the skilled technical assistance of MissDaniela Ceccarelli.     

Distribution of polyamine oxidase activity in rat tissues and subcellular fractions.

The activity of polyamine oxidase (PAO) in rat tissues, and its subcellular distribution, were assayed using a simple polarographic method. The highest PAO activity was measured in the liver and the lowest in the skeletal muscle. In liver, kidney and uterus the highest specific PAO activity was found in the light mitochondrial fraction. PAO was not found in the microsomal fraction except in the kidney.     

Causes of zonal distribution of glycogen in the liver acinus after a fat-rich diet

Zusammenfassung Nachweis, dass nach fettreicher Diät Glykogen hauptsächlich in der Zone 1 des Rappaportschen Leberacinus abgelagert wird, was durch den Abbau von Enzymen, die in den Zonen 2 und 3 am Glykogenaufbau beteiligt sind und durch die physiologische Regeneration in der Zone 1 verursacht wird.

---

---

Acknowledgments. The authors are grateful to Prof.A. de Minjer and Prof.L. W. J. Holleman for support and stimulating discussions. We acknowledge Mr.G. Tuit and MissT. Deijs for skilful technical assistance and Mr.A. J. H. Hosemans for preparing photomicrographs.     

Changes in transglutaminase activity in carbon tetrachloride-damaged rat liver.

A significant decrease in transglutaminase (TGase) activity was observed in the cytosol and nuclear fractions of carbon tetrachloride-damaged rat liver. The degree of decrease in TGase activity in the cytosol fraction was closely related to the serum transaminase level. Gel filtration studies revealed that TGase activity in 80 kDa fractions significantly decreased, but that in 160 kDa fractions slightly increased after carbon tetrachloride treatment.     

A histochemical study of succinic dehydrogenase activity in rat liver cancerogenesis induced by 3-methyl-4-dimethylaminoazobenzene

Résumé L'auteur a étudié histochimiquement l'activité de la succine déhydrogénase lors de la cancérogénèse expérimentale du foie des rats induite par le 3'-méthyl-4-diméthylaminoazobenzène. On a observé une augmentation de l'activité enzymatique dans les stades précancéreux (cholangiofibrose et hypertrophie parenchymateuse) suivie d'une diminution et disparition de cette activité dans les tumeurs développés.     

Localization of acid phosphatases in the cell fractions of chick liver

Summary 3 molecular forms (P1, P2 and P3) of acid phosphatase (E.C.3.1.3.2) have been detected in chicken liver homogenate. The different intracellular localization of these molecules has been demonstrated by cellular fractionation and electrophoretic analysis. P1 and P2 phosphatases are both present in the particulate fraction. P3 is present in a pure form in the soluble fraction. The difference between the enzyme molecules present in the particulate fraction and that in the soluble one is confirmed by the different activation-inhibition effect of various ions and substances on the enzymatic activity of subcellular fractions.     

Distribution of polyamine oxidase activity in rat tissues and subcellular fractions

The activity of polyamine oxidase (PAO) in rat tissues, and its subcellular distribution, were assayed using a simple polarographic method. The highest PAO activity was measured in the liver and the lowest in the skeletal muscle. In liver, kidney and uterus the highest specific PAO activity was found in the light mitochondrial fraction. PAO was not found in the microsomal fraction except in the kidney.