Coprophagy in the germfree mouse

Coprophagy was observed in germfree (GF) ICR mice of both sexes, and the results were compared with those of conventional mice. Frequency of coprophagy per animal per day in GF mice was 5.1 in males and 5.8 in females. In conventional (CV) mice, the frequencies were 6.2 in males and 5.3 in females (data from Zoological Science 2:249-255, 1985), with no significant differences compared with GF mice. Coprophagy in CV mice was frequently observed during 6-8 hr after lighting, whereas such close time relationships tended to weaken in GF animals. In a comparison of levels of constituents per unit weight between feces and diet, fecal crude protein and crude fat exhibited lower values than those in the diet. Levels of fecal crude ash and crude fiber were higher than those in the diet, and nitrogen-free extract was almost equal to that in the diet. No essential difference in these tendencies was found compared with CV mice. Levels of fecal vitamin B1, B2, B12 and folic acid were lower than those in the diet. In CV mice, except for vitamin B1, these vitamins exhibited either almost equal or much higher levels compared with those in the diet (data from Experimental Animals 35: 381-386, 1986). From the fact that coprophagy was observed in GF mice, it is suggested that the behavior is inherent in the mouse.     

Immunohistochemical localization of gamma-aminobutyric acid (GABA) in the rat pancreas

The localization of gamma-aminobutyric acid (GABA) in rat pancreas was investigated using antiserum raised against GABA conjugated to bovine serum albumin with glutaraldehyde. Immunoreactive cells were only found in the center of the pancreatic islets, and these cells were surrounded by nonimmunoreactive cells. When two serial sections of rat pancreas were consecutively stained with GABA antiserum and with antibodies against insulin, both antisera stained the same population of endocrine cells within the islets. In rats pretreated with streptozotocin, a B-cell toxin, we observed a marked decrease in the number of cells exhibiting GABA-like immunoreactivity. These observations indicate that GABA is present in the B cells of rat pancreatic islets.     

Isolation and partial characterization of a novel form of low molecular weight kininogen from guinea pig plasma

Two kinds of low molecular weight kininogen (termed LK1 and LK2) were isolated from pooled plasma of guinea pigs. When polyclonal antisera raised against the individual proteins were used, immunological cross-reactions were observed between LK1 and high molecular weight kininogen (HK), but not either between LK1 and LK2 or between LK2 and HK. After tissue injury, plasma level of LK1 doubled while those of LK2 and HK remained relatively unchanged.     

Decrease in CuZn-superoxide dismutase mRNA level during differentiation of human monocytic and promyelotic leukemia cells

Change in the level of CuZn-superoxide dismutase (SOD) mRNA was examined using a molecular probe during differentiation of human monocytic leukemia U937 cells or promyelotic leukemia HL-60 cells induced by either 12-O-tetradecanoyl-phorbol-13-acetate (TPA) or dimethylsulfoxide (DMSO). CuZn-SOD mRNA levels were found to decrease during the course of differentiation, and this response is specific for differentiation, since the treatment of human B cell leukemia cells or normal diploid fibroblasts with TPA failed to have any effect on the level of CuZn-SOD mRNA. The activity of CuZn-SOD in U937 cells also decreased during differentiation, but following that of the CuZn-SOD mRNA level. The expression of the CuZn-SOD gene is thus concluded to diminish during the differentiation of HL-60 and U937 cells.     

Isolation and sequence determination of rat cardiac natriuretic peptide

We have isolated a cardiac natriuretic peptide of 5K daltons from the rat atrium and determined its amino acid sequence. The 5K cardiac natriuretic peptide was elucidated to be a 45-amino acid peptide with the sequence of S-Q-D-S-A-F-R-I-Q-E-R-L-R-N-S-K-M-A-H-S-S-S-C-F-G-Q-K-I-D-R-I-G-A-V-S-R- L-G-C-D - G-L-R-L-F by sequencing the native peptide and its lysyl endopeptidase digests. The sequence of this peptide was identical to the amino acid sequence [51-95] of the rat brain natriuretic peptide (BNP) precursor deduced from the cDNA sequence. The 5K cardiac natriuretic peptide, or BNP[51-95], was identified as the major storage and secretory form derived from the BNP precursor in the rat heart.     

Endothelin in human plasma and culture medium of aortic endothelial cells--detection and characterization with radioimmunoassay using monoclonal antibody

We have developed monoclonal (KY-ET-1-I) and polyclonal (ET-F5) antibodies against endothelin-1 (ET-1) and established sensitive radioimmunoassays (RIAs) with different specificities. The RIA with KY-ET-1-I detected ET-1, ET-2 and ET-3, while the RIA with ET-F5 recognized ET-3 very weakly. Using these RIAs, we have investigated the concentration and molecular forms of ET-1-like immunoreactivity (-LI) in culture medium of bovine aortic endothelial cells and human plasma. Culture medium of endothelial cells contained two major components compatible with big ET and ET-1. ET-1-LI was also detected in human plasma. ET-1-LI in human plasma consisted of apparent two components, the small molecular form emerging at the position of ET-1 and the large form with the peak eluting at the preceding fraction of the elution position of big ET. The concentration of the small form of ET in human plasma was about 5 pg/ml.     

Detection and characterization of endothelin-1-like immunoreactivity in rat plasma

Using two radioimmunoassays (RIAs) for endothelin-1 (ET-1) with and without a substantial cross-reactivity with ET-3, we have measured the plasma ET-1-like immunoreactivity (-LI) level in rat plasma. ET-1-LI was detected in plasma from male Wistar rats. ET-1-LI in rat plasma consisted of three components with molecular weights of 6K, 4K and 2.5K daltons by gel permeation chromatography. Two of the components were eluted at positions of big ET (4K) and synthetic ET-1 (2.5K). The remaining component was eluted at the preceding fraction (6K). No difference was observed in ET-1-LI of the small molecular form of ET (2.5K) between the two RIAs. Thus, there is little or no ET-3 in rat plasma, which has the sequence found originally in the rat genome. The concentration of the small molecular form of ET, presumably ET-1, in rat plasma was about 4 pg/ml.     

Molecular cloning of cDNA for sarcocystatin A and analysis of the expression of the sarcocystatin A gene during development of Sarcophaga peregrina

Sarcocystatin A is a cysteine proteinase inhibitor purified from the hemolymph of Sarcophaga peregrina larvae [Suzuki, T., & Natori, S. (1985) J. Biol. Chem. 260, 5115-5120]. We isolated a cDNA clone for sarcocystatin A and analyzed the structure and expression of the sarcocystatin A gene. Sarcocystatin A consists of 102 amino acid residues. Significant homology was found between amino acid sequences of sarcocystatin A and other mammalian cystatins, and highly conserved sequences among mammalian cystatins were also found in sarcocystatin A. Using cloned cDNA as a probe, we investigated expression of the sarcocystatin A gene during the development of Sarcophaga. Results showed that this gene was transiently activated in the very early embryonic stage and in the pupal stage, suggesting that sarcocystatin A participates in morphogenesis of larval and adult structures of Sarcophaga.     

Immunohistochemical localization of proteoglycans in interstitial elements of human pancreas and biliary system

Summary The immunohistochemical localization of large proteoglycan and small proteoglycan was observed, using antibodies 2B1 and 6B6 (Sobueet al., 1988, 1989a), in fetal and adult pancreas and biliary system as well as in tumour tissues, obtained from 11 autopsies and 74 biopsies. The distribution of chondroitin 4- and 6-sulphate side chains, type I and IV collagen and elastin were also studied. In adult pancreas and all the biliary tracts examined, periductal fibrous tissues consisted mainly of dermatan sulphate small proteoglycan with networks of fibrous elements, which were composed of large proteoglycan, elastin, type I collagen and type IV collagen. In the interstitial components of cystadenoma of pancreas and biliary duct carcinoma, similar small proteoglycan-rich components were relatively abundant, although large proteoglycan was present in much larger amounts than that in non-neoplastic adult tissues. In some cholangiomas, the extra-and intracellular hyaline globules formed by the carcinoma cells were found to contain chondroitin sulphate large proteoglycan, laminin and fibronectin.The distribution of proteoglycans was observed to be different in the arterial walls of the interlobular tissues of the adult and the fetal pancreas. The biological significance of large and small proteoglycans in the interstitial connective tissues was discussed.     

Heterogeneity of big-big hPRL in hyperprolactinemia

Sera from a patient with macroprolactinoma (case 1) and from a hyperprolactinemic woman with regular menstruation (case 2) were analyzed for prolactin activity by gel filtration using Sephadex G-100, Sephadex G-200 and TSK G3000SW columns. The chromatographic profile by Sephadex G-100 showed that the percentage of immunoreactive big-big hPRL was 10.7% in case 1 and 64.1% in case 2. On Sephadex G-200 and TSK G3000SW columns, the molecular weight of big-big hPRL was estimated to be more than 500,000 daltons (big-big1 hPRL) in case 1 and approximately 250,000-300,000 daltons (big-big2 hPRL) in case 2. Big-big1 hPRL in case 1 was converted to big and little hPRLs when the serum was treated with 2-mercaptoethanol (2-ME), but part of the big-big2 hPRL in case 2 was converted to a larger molecule. Radioactive big-big hPRL generated by mixing labeled hPRL with the serum from case 1 was eluted with the void volume on Sephadex G-100 column and was not converted to the other molecular forms after 2-ME treatment. There were two radioactive big-big hPRL on TSK G3000SW column and these estimated molecular weights were more than 300,000 daltons. The data demonstrated the existence of at least two forms of big-big hPRL in the serum and indicated that radioactive big-big hPRL may be different from these hPRLs in the serum.