Presence of albumin mRNA precursors in nuclei of analbuminemic rat liver lacking cytoplasmic albumin mRNA

Analbuminemic rats, which lack serum albumin, were previously found to have no albumin mRNA in the cytoplasm of the liver. In the present study, the existence of nuclear albumin mRNA precursors in the liver of analbuminemic rats was examined by RNA X cDNA hybridization kinetics. Albumin mRNA precursors were present in the nuclei of analbuminemic rat liver at almost normal levels, despite the absence of albumin mRNA from the cytoplasm. Nuclear RNA of analbuminemic rat liver was subjected to electrophoresis on 1% agarose gel in parallel with nuclear RNA of normal rat liver. RNA was transferred from the gel to diazobenzyloxymethyl-paper and hybridized to cloned cDNA. Several bands of putative albumin mRNA precursors were obtained with nuclear RNA of analbuminemic rat liver and some of them were indistinguishable from those of normal rat liver. Nuclear RNA of analbuminemic rats was hybridized to 3'-end-labeled cloned cDNA under the conditions of RNA excess and then digested completely with S1 nuclease and subjected to electrophoresis on polyacrylamide gel. By this technique, nuclear RNA that could hybridized to cDNA was found to have the albumin mRNA sequence in at least the 3' half of the mRNa that was covered by cloned cDNA. For comparison of the structures of the albumin genes of analbuminemic and normal rats, DNAs from rat livers of both types were digested completely with EcoRI, HindIII, and Pst I; the fragments were separated by electrophoresis on 1% agarose gel, transferred to nitrocellulose paper, and hybridized to cloned cDNA. The intensities of the corresponding bands and the digestion patterns of the analbuminemic and normal rat genes were indistinguishable. From these data, it is concluded that analbuminemic rats have a unique type of mutation(s) affecting albumin mRNA maturation.

Perinatal changes of alpha-fetoprotein concentration in the serum and its synthesis in the liver of analbuminemic rats

The profile of appearance of disappearance of alpha-fetoprotein (AFP) in the serum of analbuminemic rats, which have a genetically controlled lack of serum albumin, was studied. During the perinatal stage, AFP was present in the serum of analbuminemic rats, its concentration at birth being 10 mg/ml as in normal rats. In analbuminemic rats, the concentration of serum AFP remained at about 10 mg/ml during the first week after birth and then decreased rapidly during the next 2 weeks, becoming undetectable about 4 weeks after birth. In normal rats, the serum AFP concentration reached a maximum of 11.5 mg/ml at birth and then decreased sharply to an undetectable level within 4 weeks after birth, although a small rebound of AFP concentration was observed about 1 week after birth. AFP synthesis in analbuminemic and normal rats was examined by injecting [3H]leucine i.p. and then measuring the radioactivity incorporated into the acid-insoluble fraction and immunoprecipitable fraction using anti-AFP antiserum. In analbuminemic rats, synthesis of AFP amounted to 7.5% of the total protein synthesis at birth and was maintained at about 7% of the total for the first week after birth and then decreased to 2% at 2 weeks after birth. In normal rats, AFP synthesis also amounted to 7.5% of the total protein synthesis at birth but decreased to about 2% at 2 days after birth and then remained at a low level for about 2 weeks. In both normal and analbuminemic rats, AFP synthesis was undetectable at 4 weeks after birth. These data show that AFP synthesis is shutoff after birth irrespective of the serum albumin concentration during neonatal development.

[Clinico-biochemical study on Ishibashi rats (author's transl)]

Ishibashi rats, a mutant strain with congenital spinal malformation discovered by Ishibashi in 1968, are generally regarded as an animal model for a human inborn error of spinal malformation. Biochemical values in serum or plasma of Ishibashi rats were compared with those of Wistar-Imamichi rats, and the following results were obtained: 1) In Ishibashi rat sera, alkaline phosphatase activity was significantly lower than that in sera of controls, and an intestinal type of isozyme was hardly detected. 2) All other serum biochemical parameters examined showed no significant difference between Ishibashi and Wistar-Imamichi rats. 3) The data suggest that Ishibashi rats may serve as an animal model of hypophosphatasia in man.

Changes of amylase during experimental pancreatic carcinogenesis in hamsters

Changes of amylase activity and isozymic pattern in the serum, urine, ascites, pancreas and parotid gland of hamsters during pancreatic carcinogenesis induced by N-nitrosobis (2-oxopropyl) amine (BOP) were examined. During the early stage of pancreatic carcinogenesis, amylase activity in the urine was greatly increased and the pancreatic type of isozyme increased in the serum and urine, but in the terminal stage, the activity decreased and the isozymic pattern reverted to normal. These alterations of amylase could be due to focal pancreatitis around dysplastic ductules and small carcinoma lesions causing leakage of pancreatic juice. This phenomenon may be of value in diagnosis of the early stage of pancreatic cancer.

Establishment of an albumin-deficient and jaundiced strain of rats

An albumin deficient and jaundiced rat (AJR) strain was established from crosses between Albumin-Deficient rats (NAR) and jaundiced Gunn rats. AJRs have a double homozygous mutant trait (alb/alb, j/j), and systemic jaundice and various neurological signs are observed 5--7 days after birth, kernicterus occurs and they die within three weeks after birth. This strain of rats may serve as a model of human kernicterus and also be useful in elucidating the mechanism of bilirubin metabolism.

Isolation and characterization of proteodermatansulfate from rat skin

A proteodermatansulfate was extracted from rat skin with 4 M guanidine hydrochloride containing protease inhibitors at 4 degrees C. It was separated from collagen on DEAE-cellulose in 7 M urea and was purified by cesium chloride density gradient centrifugation under associative conditions, DEAE-Sephadex column chromatography and then Sephadex G-200 gel filtration. On SDS-disc electrophoresis, the proteoglycan gave a single band staining for protein and a band of the same mobility staining with periodate-Schiff reagent. The proteoglycan contained 46% protein, and this was bound to dermatansulfate via an O-glycosidic linkage. The proteoglycan also contained 20% uronic acid and 16% hexosamine, but no detectable hydroxyproline. The ratio of galactosamine to glucosamine was 68. The dermatansulfate, the only glycosaminoglycan, had a hybrid structure containing iduronic acid and glucuronic acid as uronic acids. The content of glucuronic acid in uronic acid was much higher than that of pig skin dermatansulfate. The dermatansulfate had a slightly higher mobility on cellulose acetate electrophoresis than those from other sources. Gel chromatography on Sepharose CL-6B showed that the molecular weight of the dermatansulfate was 23,000, while that of the proteoglycan was 36,000. The elution profile of a mixture of the proteoglycan and hyaluronic acid on Sepharose 6B column chromatography was similar to that of the proteoglycan alone.

Absence of albumin in tissues of analbuminemic rats

Nagase analbuminemic rats (NAR) are deficient in serum albumin. Extravascular regions of the tissues of NAR were tested for rat serum albumin by the immunofluorescence staining technique. Albumin was not detectable in any of the tissues of NAR tested (liver, kidney, muscle, skin, and small intestine), whereas it was clearly demonstrated in all these tissues of normal rats. Furthermore, extracts of NAR tissues, including the liver, contained no albumin detectable by the single radial immunodiffusion method. These findings indicate that albumin is not present in either the serum or extravascular regions of tissues of NAR, and suggest that the deficiency of serum albumin in NAR is not due to impaired albumin secretion from the liver or alteration of the tissue distribution of albumin in certain tissues, but to the absence of its synthesis in the liver.

Characterization of hyperlipidemia in Nagase analbuminemia rat (NAR)

The mutant analbuminemia rat (NAR) was recently reported by Nagase (1) to spontaneously develop hypercholesterolemia. A detailed lipid analysis was carried out to characterize the hyperlipidemia. The concentrations of major phospholipids as well as cholesterol were increased in plasma, whereas the triacylglycerol level remained unchanged. Free fatty acid and lysophosphatidylcholine levels, on the contrary, declined. The liver lipids were not accumulated, but appeared to be depleted.

Absence of albumin mRNA in the liver of analbuminemic rats

Albumin synthesis in the liver of analbuminemic rats, established as a strain from a stock of Sprague-Dawley rats, was examined in vivo by labeling protein by intraperitoneal injection of L-[3H]leucine. Albumin was not synthesized in the liver of analbuminemic rats, whereas its synthesis amounted to about 14% of the total protein synthesis in the liver of normal rats. The RNA content and size distribution of the total polysomes in the liver of analbuminemic rats were not significantly different from those of normal rats. However, no functional mRNA coding for albumin was found in poly(A)-containing RNA from the liver of analbuminemic rats when tested with a cell-free translation system derived from rabbit reticulocytes. Moreover, the amount of the RNA sequence that could hybridize to purified albumin cDNA was more than 750 times greater in the liver of normal rats than in that of analbuminemic rats.

Albumin-deficient rat mutant: an animal model for analbuminemia

An analbuminemic rat colony (NAR, Nagase Analbuminemia Rat) was established from Sprague-Dawley rats. The Analbuminemia was inherited as an autosomal recessive trait. The rate of growth or propagation of the mutant rats was not different from those of normal rats. Biochemically the mutant was characterized by an extraordinarily low serum albumin and hyperlipidemia. Total protein level of the serum in the mutant rat was similar to that of control Sprague-Dawley rats and globulin increased compensatorily. Serum cholesterol concentration was inversely correlated with a decrease in albumin, its correlation coefficient was -0.92. NAR may serve as a model of human familial analbuminemia. It should be also useful in elucidating the functional roles of albumin.

[Comparative studies on release of enzymes from platelets during blood clotting in Rattus rattus flavitecus and Rattus norvegicus (author's transl)]

Increase of lactate dehydrogenase (EC 1.1.1.28) and creatine kinase (EC 2.7.3.2) in serum and plasma level during blood clotting was compared in R. rattus flavitectus (black rat) and R. norvegicus (albino rat). Both the enzyme level increased by the release from platelets in process of clotting in rat as previously described (Emori T., Takahashi M. and Nagase S. (1978) Exp. Animals, 27, 167), but the change in black rat was very slight. Owing to search for the reason to prove the difference in this phenomenon, physiological and chemical properties of blood from both the animals were compared, and it was demonstrated that the content of plasma fibrinogen in black rat is higher than that in albino rat, while the platelet number contained in each ml of blood and the enzyme activities in each platelet are not different between them. The analysis of the membrane proteins from platelets of both the animals by SDS-polyacrylamide gel electrophoresis showed that the fractional value of glycoproteins was found to be different between them.

Albumin-deficient rat mutant

An analbuminemic colony was established from Sprague-Dawley rats. Analbuminemia was inherited as an autosomal recessive trait. The rates of growth and reproduction of the mutant rats were no different from those of normal rats. Biochemically, the mutant was characterized by an extraordinarily low serum albumin content and a hyperlipidemia. Total serum protein in the mutant rat was similar to that of control Sprague-Dawley rats, with increased globulin. Serum cholesterol was inversely correlated with a decrease in albumin; the correlation coefficient for ablumin was --.92. These mutant rats may serve as a model of human familial analbuminemia and may also be useful in elucidating the functional roles of albumin.

[A simplified method for determination of biochemical marker genes in inbred strains of mice (author's transl)]

A rapid method is described for the determination of biochemical variants of mice by Titan III cellulose acetate electrophoresis. Variants examined were hemoglobin beta-chain, serum esterase-1, malic enzyme (supernatant form), and isocitrate dehydrogenase (supernatant form). The present procedure can be recommended as a simplified method to analyze biochemical variants for checking of marker genes in inbred strains of mice.

[Comparative studies on lactate dehydrogenase in serum and plasma of rats (author's transl)]

Values of serum and plasma LDH in rats were comparatively studied, and the following results were obtained: 1) The activity of LDH increased in serum with time during clotting, but no changes of LDH activity were found in plasma. 2) When platelet rich plasma (PRP) was recalcified and allowed to clot, LDH-release from platelets with a corresponding increase of serum LDH was observed, but addition of ADP or thrombin to PRP did not have an effect on LDH-release. 3) LDH-release from platelets by calcium was not inhibited by aspirin, and it was influenced by the quality of the test tube. 4) Values of serum and plasma LDH on experimentally induced liver-damaged or kidney-damaged rats and tumor-bearing rats were examined in relation to their tissue damages, revealing that plasma LDH activity represents the condition of a disease better than serum LDH activity.

Mucopolysaccharides of rat ascites hepatoma, AH-100B

The present study was undertaken to determine the mucopolysaccharide content of cells, AH-100B, and in the ascites, liver, and kidney of a rat bearing this hepatoma. AH-100B is similar to other mixed-type cells in having heparan sulfate as the main component in its mucopolysaccharides but its minor component was different in containing heparin. The main mucopolysaccharide in the ascites of AH-100B bearing rat was hyaluronic acid, which was similar to that of control ascites induced by injection of polypeptone, but minor component contained heparin derived from the cells. The content of hyaluronic acid in the liver of a rat bearing this hepatoma was higher than those of control liver and liver of a rat bearing other tumors. There were no significant differences between control kidney and kidney of a rat bearing this hepatoma.