Evidence for existence of somatostatin-like immunoreactivity with molecular heterogeneity in porcine ovaries

Measurement of somatostatin (SRIF) by RIA in porcine ovarian tissues after removal of the follicular fluid revealed the existence of immunoreactive (IR) SRIF at concentrations of 2.2 +/- 0.6 ng/g wet weight (mean +/- SD). On gel chromatographic analysis of ovarian extracts one major and two minor components with SRIF-like immunoreactivities have been detected. The major component comprised 59.5 +/- 15.1% of the total IR-SRIF and was coeluted with synthetic tetradecapeptide (SRIF 14). The two other components seemed to have almost the same molecular weights as synthetic octacosapeptide (SRIF 28) (25.1 +/- 10%) and pro-somatostatin (15.4 +/- 5.5%), respectively. It is concluded that SRIF in porcine ovaries is heterogeneous, comprising SRIF 14 as a major component, as well as larger forms of SRIF which probably represent SRIF precursors.

Stimulant effects of W-7, a calmodulin-antagonist, on renin release from rat kidney cortical slices

Effects of N-(6-aminohexyl)-5-chloro-1-naphthalenesulfonamide (W-7), a calmodulin-antagonist, on renin release was examined using rat kidney cortical slices. Although the amounts of renin release from the slices were stable during incubation of 3 consecutive 15 min periods in Krebs-Ringer bicarbonate solution (pH 7.4), the addition of W-7 to the incubation medium resulted in a concentration-dependent increase in renin release from the slices. The stimulant effect of W-7 on renin release was abolished by the removal of calcium from the incubation medium. These results suggest that the inhibition of the calcium-calmodulin system leads to the stimulation of renin release from rat kidney cortical slices.

Effects of dietary fats and phytosterol on serum fatty acid composition and lipoprotein cholesterol in rats

The effects of dietary fats and phytosterol on the fatty acid composition and lipoprotein cholesterol in serum were studied in female rats, with the following results. (1) The addition of 1% cholesterol to the 20% butter diet decreased the ratio of polyunsaturated fatty acid (PUFA) to saturated fatty acid (SFA) in serum. This phenomenon was negated when there was an intake of cod liver oil and wheat germ oil. (2) When cholesterol was added to the 20% butter diet, the serum total cholesterol increased 3.7-fold, due to an increase in the lower density lipoprotein (LDL + VLDL). (3) The addition of 5% phytosterol to the 10% butter-cholesterol diet reduced the total cholesterol level and increased the ratio of cholesterol in high density lipoprotein (HDL) to the cholesterol in LDL + VLDL. Although a 10% cod liver oil addition also reduced the total cholesterol level, the ratio of HDL/LDL + VLDL was similar to that of the 10% butter-cholesterol diet. (4) A direct relationship was found between the concentration of oleic acid (18:1) in serum and the total cholesterol level (r = 0.947) and also the level of LDL + VLDL-cholesterol (r = 0.935). These results show that cod liver oil, wheat germ oil, and phytosterol induce an increase in the PUFA/SFA ratio, promote hypocholesterolemia, and change lipoprotein concentration. However, there were indications that no relationship exists between the change in the total cholesterol level and the change in the ratio of HDL/LDL + VLDL, and that the increase of total cholesterol and LDL + VLDL-cholesterol was consistent with the increase of oleic acid in serum.

An international study of smoking and bladder cancer

The effects of smoking cigarettes and other forms of tobacco on the development of cancer of the lower urinary tract (bladder cancer) were evaluated in Boston, Massachusetts, Manchester, United Kingdom and Nagoya, Japan. Population-based series of incident cases and controls were identified and interviewed in each area. The present analyses were based on 592 cases and 533 controls in Boston, 553 cases and 731 controls in Manchester, and 290 cases and 588 controls in Nagoya. Smokers of cigarettes had about twice the incidence of bladder cancer as nonsmokers. In men the strength of the association between cigarette smoking and bladder cancer was similar in the 3 study areas. The strength of the association varied somewhat from area to area among women. Bladder cancer risk increased with frequency of cigarette smoking and with deep inhaling. In Boston men who smoked 2 or more packs of cigarettes per day and inhaled deeply had nearly 7 times the risk of nonsmokers. Ex-smokers had a level of risk between that of current smokers and nonsmokers. However, there was no clear relationship between risk and age at which cigarette smoking began, time since discontinuation among ex-smokers and use of filters. Over-all, there was little difference in bladder cancer risk between men who had and who had not smoked pipes but pipe smoking did appear to be associated with risk among men who had never smoked cigarettes. Cigar smoking was unrelated to bladder cancer.

Differentiation induction of murine erythroleukemia cells by butylated hydroxytoluene

Butylated hydroxytoluene (BHT) which is widely used as an anti-oxidant in food has been found to induce the differentiation of murine erythroleukemia cells. BHT also amplifies the differentiation inducing activity of DMSO.

Indomethacin augments inhibitory effects of interferons on lymphoproliferative response

Lectin-induced lymphoproliferative response was enhanced by the addition of indomethacin to the culture and in contrast, suppressed by the addition of interferon. However, when indomethacin and interferon were concomitantly present in the lectin-driven cultures, the suppressive effect of interferon on the lymphocyte blastogenesis surpassed the enhancing effect of indomethacin on the response. Furthermore, and unexpectedly, the inhibitory effect on the response due to interferon was definitely augmented in the presence of indomethacin as compared with the response in the absence of indomethacin.

Development of adenocarcinomas after transplantation of rat glandular stomachs treated in vitro with N-methyl-N'-nitro-N-nitrosoguanidine (MNNG)

Glandular stomachs of fetal and newborn Wistar rats were transplanted s.c. after treatment in vitro with N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) at concentrations of 10, 5 and 1 microgram/ml for 2 h. Eleven adenocarcinomas developed from 118 MNNG-treated transplants, whereas no adenocarcinomas developed from 28 untreated transplants. The incidence of adenocarcinomas in fetal glandular stomach (9/46) was significantly different (p less than 0.01) from that in glandular stomach of newborn rats (2/67). Various types of mesenchymal tumors also developed from untreated (9/28) and MNNG-treated (20/118) transplants.

New method for quantitative measurement of N-nitrosodimethylamine formation in the whole mouse

A simple method for the quantitative estimation of the formation of N-nitrosodimethylamine (NDMA) in mice has been developed. Mice were frozen in liquid nitrogen and homogenized. NDMA was then extracted and analyzed by a gas chromatograph equipped with a thermal energy analyzer. In normal mice NDMA (100 nmole) administered orally was rapidly metabolized and recovery of NDMA was about 10% after 60 min. However, when pyrazole (300 mg/kg) was injected i.p. to mice 60 min before the administration of NDMA, more than 80% of the administered NDMA could be recovered within 60 min. This result suggested that in pyrazole pretreated mice the accurate amount of NDMA formed could be estimated. Therefore the NDMA formation was measured in the pyrazole pretreated mice. When 0.25 mumole of aminopyrine and from 0.25 to 2.0 mumole of sodium nitrite were simultaneously administered orally, the amount of the NDMA formation in 20 min was found to be from 8.2 to 60.3 nmole. These values are equal to about from 30 to 200 micrograms/kg of body weight which are nearly daily doses expected to cause the carcinogenic effect on mice or rats. This method of measuring NDMA in pyrazole pretreated mice appears to be useful for investigating the in vivo formation of NDMA quantitatively.

Stimulation of renin release from rat kidney cortical slices by vitamin E-deficiency

Effect of vitamin E-deficiency on renin release was examined with rat kidney cortical slices. Male Wistar rats were fed either a control or a vitamin E-deficient diet for 4 weeks. When kidney cortical slices were incubated in a Krebs-Ringers' bicarbonate solution (pH 7.4) at 37 degrees C, the rate of renin release into the incubation medium in vitamin E-deficient group was significantly higher than that in the control group. However, dietary supplementation of alpha-tocopheryl acetate (TOCA) or N,N'-diphenyl-p-phenylenediamine (DPPD) to the vitamin E-deficient rats for 5 d suppressed the stimulation of renin release from kidney cortical slices by vitamin E-deficiency. On the other hand, the release of protein, acid phosphatase and alkaline phosphatase during incubation of kidney cortical slices was not affected by vitamin E-deficiency or supplementations of TOCA and DPPD. These findings indicate that vitamin E-deficiency specifically stimulates renin release from kidney cortical slices and this effect is attenuated by the dietary supplementation of TOCA or DPPD.

Effects of vitamin E depletion and repletion on renin release from renin granules

The present study was carried out to investigate the effects of vitamin E-deficiency and supplementation of alpha-tocopheryl acetate (TOCA) on renin release from renin granules. Male Wistar rats were fed either a control or a vitamin E-deficient diet for 4 weeks. Subsequently, the vitamin E-deficient rats received dietary supplementation of TOCA (40 mg/100 g diet) for 5 d. The renin granule fraction was prepared from the kidney cortex homogenate by a discontinuous sucrose density gradient centrifugation. The intake of vitamin E-deficient diet for 4 weeks resulted in an increased level of endogenous lipid peroxides in the renin granule fraction, accompanied by a marked decrease in alpha-tocopherol content, and led to a significant increase in the rate of renin release from the granules during incubation at 37 degrees C. These changes in alpha-tocopherol content, lipid peroxide level and renin release in the renin granule fraction were restored to the control values by dietary TOCA supplementation. Similarly, dietary supplementation of N,N'-diphenyl-p-phenylenediamine (80 mg/100 g diet), which has an antioxidative ability, suppressed the increases in lipid peroxidation and renin release due to vitamin E-deficiency, although this compound was ineffective in restoring alpha-tocopherol levels. These results suggest that vitamin E functions in maintenance of membrane integrity of renin granules by inhibiting the lipid peroxidation.

Enhancement by potassium bromate of renal tumorigenesis initiated by N-ethyl-N-hydroxyethylnitrosamine in F-344 rats

The effect of potassium bromate, a food additive, was examined in male F-344 rats based on two-stage renal carcinogenesis with N-ethyl-N-hydroxyethylnitrosamine (EHEN) as an initiator. Average numbers of dysplastic foci and renal cell tumors were significantly increased in rats given potassium bromate after initiation with EHEN. It was concluded that potassium bromate has an enhancing effect on renal tumorigenesis.

Effect of phenobarbital and 3-methylcholanthrene on the hepatic microsomal metabolism of N-nitrosodimethylamine, N-nitrosomethylbutylamine and N-nitrosomethylbenzylamine

The effect of phenobarbital (PB) and 3-methylcholanthrene (MC) pretreatment on dealkylations of N-nitrosodimethylamine (NDMA), N-nitrosomethylbutylamine (NMBuA) and N-nitrosomethylbenzylamine (NMBeA) was investigated in rat hepatic microsomes. PB increased the demethylation and the debutylation of NMBuA and the debenzylation of NMBeA. MC increased the debutylation of NMBuA and the debenzylation of NMBeA. However, MC decreased the demethylation of NMBeA. The demethylation of NDMA was not changed by the pretreatment of the inducers. These results suggest that the dealkylations of these nitrosamines are catalyzed by several enzymes, which probably depend on different cytochrome P-450 species.

Renin release and lipid peroxidation by ascorbic acid in the renin granule fraction of rat kidney cortex

This study was carried out to investigate the effect of lipid peroxidation in the renin granule fraction on renin release from the granules. Ascorbic acid was used to cause lipid peroxidation in the renin granule fraction prepared from rat kidney cortex homogenate. Renin activity was measured by radioimmunoassay and lipid peroxidation was estimated by means of the thiobarbituric acid test. Ascorbic acid, at the concentrations from 5 to 100 microM, produced a dose-dependent increase in lipid peroxidation during incubation of the renin granule fraction at 37 degrees C for 30 min, accompanied by increased release of renin from the granules. On the other hand, dehydroascorbic acid showed no effects on lipid peroxidation and renin release. The simultaneous increases in lipid peroxidation and renin release induced by ascorbic acid in the renin granule fraction were markedly suppressed by the addition of disodium ethylenediaminetetra-acetic acid and antioxidants such as N,N'-diphenyl-p-phenylenediamine and hydroquinone. These findings indicate that lipid peroxidation in the renin granule fraction results in the stimulation of renin release from the granules.

A possible role of "steroidogenic factor" in the corticoidogenic response to ACTH; effect of ACTH, cycloheximide and aminoglutethimide on the content of cholesterol in the outer and inner mitochondrial membrane of rat adrenal cortex

The role of a "steriodogenic factor" in the corticoidogenic response to adrenocorticotropic hormone (ACTH) was studied in this experiment. ACTH caused an accumulation of cholesterol within the adrenocortical mitochondria in rat after pretreatment with either cycloheximide (CH) or aminoglutethimide (AG). The cholesterol distribution in these cholesterol-rich mitochondria was examined by measuring the cholesterol concentrations in the outer and inner mitochondrial membranes. In the case of pretreatment with CH, cholesterol was accumulated in the outer membrane and not in the inner membrane. In contrast, in the case of pretreatment with AG, cholesterol was accumulated in the inner membrane and not in the outer membrane. It could be concluded from the presented data that the function of a "steroidogenic factor" in the corticoidogenic response to ACTH might take place at the step of cholesterol translocation from the outer mitochondrial membrane to the inner membrane.

Sero-epizootiological study on swine influenza in a prefecture of Japan

A total of 1799 swine sera collected in Toyama prefecture in the central part of Japan during the years 1978-82 were tested for antibody against swine influenza virus (SIV), A/New Jersey/8/76 (H1N1). A high prevalence of antibody was observed in the years after the severe epizootic of SI, 34.5% in 1979 and 51.7% in 1982. In other years, the percentages of positive sera were low and ranged from 1.7 to 12.4%. Regional variations were seen in relation to a small scale epizootic. No antibody to SIV was detected in any of the sera collected during the warm season. In the following dry and cold winter, however, a severe epizootic occurred among the swine populations.

Spontaneous tumors in F-344/DuCrj rats

Spontaneous tumors in 296 male and 297 female F-34/DuCrj rats used as control groups in six carcinogenicity tests were tabulated and evaluated. In males the most frequent tumors were testicular interstitial cell tumors, followed by mammary fibromas and fibroadenomas, mononuclear cell leukemias, pheochromocytomas, C-cell adenomas of the thyroid, pituitary adenomas, preputial adenomas, neoplastic nodules of the liver, and lung adenomas. In contrast, in females pituitary adenomas, uterine endometrial stromal polyps, mammary fibroadenomas, mononuclear cell leukemias and C-cell adenomas were the most common. Various other tumors of almost all other organs and/or tissues were found, although their incidences were low. Variability in the rates of incidence in some tumors was observed in different control groups.

Influence of temperature and growth phase on desaturase activity of the mesophilic yeast Candida lipolytica

Microsomal membranes prepared from Candida lipolytica cells grown at 10 degrees C had a higher lipid content and degree of unsaturation than membranes prepared from cells grown at 25 degrees C. The specific activities of stearoyl-CoA (18:0-CoA), oleoyl-CoA (18:1-CoA), and dioleoyl phosphatidylcholine (18:1-PC) desaturases in microsomes of cells grown at either 25 or 10 degrees C showed maximum values near midlog phase, coinciding with the respective maximum absolute content of linoleic (18:2) in the microsomal preparations. The 18:1-CoA desaturase activity in 10 degrees C cells was nearly double that in 25 degrees C cells, while the 18:0-CoA and 18:1-PC desaturases had considerably lower activities in 10 degrees C cells. An increase in aeration rate (shaking speed, 70 to 130 rpm) resulted in increased proportions of 18:2 (32 to 47%, respectively) in microsomes of cells grown at 25 degrees C and in increased 18:1-CoA desaturase specific activity (83 to 140 pmol X min-1 X mg-1); however, no significant changes occurred in 18:0-CoA or 18:1-PC desaturase activities.