Effect of diabetes on the vertebral column of rats and its modification by estradiol

Summary In vertebrae of genetically selected sucrose-fed diabetic rats a statistically significant bone deficit was found after diabetes had been present for about 8 months. No osteopenia was observed in diabetic rats following treatment with estrogenic hormone for 5–7 months. The development of osseous centers in the end plates of the vertebrae was retarded in diabetic rats, but was about normal in diabetic rats given estrogen.—No differences were noted in the growth zones or in the tendency to develop articular lesions in rats of the various groups. Possible differences in the amount of GAG in intervertebral discs of diabetic and non-diabetic rats respectively await further confirmation.These investigations were aided by grant No. 2 RO1 EYO 1837-03, of the Institute of Arthritis and Metabolic Disease, National Institutes of Health, Bethesda, Maryland, USA.We are indebted to Professor Dr J. Rüttner, Institute of Pathology, University of Zürich, for his permission to use the calculator.     

Increase of collagen synthesis in pulmonary arteries of monocrotaline-treated rats

Collagen synthesis in the pulmonary artery in animals with pulmonary hypertension was studied using monocrotaline-treated rats as a model. Incorporation of 14C-lateled proline into collagenase-digestible protein in the pulmonary artery was found to be 4-5 times higher in monocrotaline-treated rats than in control rats.     

Long-term depressor effects of catecholamine neuronal grafts in the third ventricle of the brain in normotensive rats

Neuronal tissue containing A-6 group noradrenalin (NA) neurons of the locus ceruleus, or A-10 group dopamine (DA) neurons of the substantia nigra, was grafted into the third ventricle at the level of the preoptic-anterior hypothalamic region, in normotensive male rats. A significant and long-lasting depressor effect was shown in rats with either graft. In rats with an NA neuron-rich graft, plasma concentrations of arginine-vasopressin (AVP), plasma renin activity (PRA), and corticosterone (CS) decreased significantly, whereas in rats with a DA neuron-rich graft, AVP and PRA concentrations also decreased significantly but CS showed no significant change. Neither NA nor adrenalin in plasma changed significantly in rats with either graft.     

Long-term depressor effects of catecholamine neuronal grafts in the third ventricle of the brain in normotensive rats

Summary Neuronal tissue containing A-6 group noradrenalin (NA) neurons of the locus ceruleus, or A-10 group dopamine (DA) neurons of the substantia nigra, was grafted into the third ventricle at the level of the preoptic-anterior hypothalamic region, in normotensive male rats. A significant and long-lasting depressor effect was shown in rats with either graft. In rats with an NA neuron-rich graft, plasma concentrations of arginine-vasopressin (AVP), plasma renin activity (PRA), and corticosterone (CS) decreased significantly, whereas in rats with a DA neuron-rich graft, AVP and PRA concentrations also decreased significantly but CS showed no significant change. Neither NA nor adrenalin in plasma changed significantly in rats with either graft.     

Decreased number of asialoglycoprotein receptors in diabetic BB Wistar rat

The binding of asialoglycoproteins by hepatic binding protein was studied in freshly isolated hepatocytes from genetically diabetic BB Wistar rats. The number of cell surface asialoglycoprotein receptors was dramatically decreased (58,000 +/- 38,000 for diabetic rats compared to 267,000 +/- 70,000 for normal rats), while the association equilibrium constant was not changed. These results parallel those obtained with streptozotocin-diabetic rats and support the hypothesis that insulin deprivation is responsible for the decrease in the receptor number.     

Copper metabolism in the LEC rat: Involvement of induction of metallothionein and disposition of zinc and iron

The Cu concentration was about 40 times higher in the liver of LEC (Long-Evans with a cinnamon-like coat color) rats aged 77 days (227.5±21.6 g/g liver) than in Fischer rats (5.2±0.1 g/g liver). However, in the kidney and brain of the LEC rats, Cu concentrations were lower than in these organs of the Fischer rats. Cu concentration in the hepatic metallothionein fraction was about 130 times higher in the LEC rats than in the Fischer rats. The LEC rats showed markedly low concentrations of Cu in the serum and bile. It seems likely that excretion of Cu from the liver into the bile and blood (as ceruloplasmin) is inherently lacking in the LEC rat.     

The effect of guanethidine treatment of testicular blood flow and testosterone production in rats

Testicular blood flow was measured by means of Xenon-133 clearance in control rats and rats treated with guanethidine for 3 weeks. Plasma and testis testosterone concentrations were also measured, and the effect of hCG-treatment was examined. No difference in testicular blood flow between the control group and the guanethidine-treated group was found. However, in guanethidine-treated rats, plasma and testis testosterone concentrations after hCG-treatment were significantly decreased. The results may indicate that adrenergic nerves are involved in the regulation of Leydig cell function.     

The effect of guanethidine treatment of testicular blood flow and testosterone production in rats

Summary Testicular blood flow was measured bymeans of Xenon-133 clearance in control rats and rats treated with guanethidine for 3 weeks. Plasma and testis testosterone concentrations were also measured, and the effect of hCG-treatment was examined. No difference in testicular blood flow between the control group and the guanethidinetreated group was found. However, in guanethidine-treated rats, plasma and testis testosterone concentrations after hCG-treatment were significantly decreased. The results may indicate that adrenergic nerves are involved in the regulation of Leydig cell function.     

Effect of a restricted diet on the in vitro glucose-induced insulin release of aging rats.

To study the effect of a sudden loss of body weight on the beta-cell function of aging rats, basal and glucose-induced insulin secretion was measured in pancreatic islets obtained from young (2-month-old), adult (12-month-old) and aging (24-month-old) rats, either fed ad libitum or fed a restricted diet (50% caloric restriction). Basal insulin secretion was similar in islets of young, adult and older rats. Glucose stimulated insulin release was significantly reduced in aging rats as compared to young animals. Animals fed a restricted diet showed a prolonged and higher secretory rate during first phase release when compared to animals fed ad libitum.     

Decreased number of asialoglycoprotein receptors in diabetic BB Wistar rat

Summary The binding of asialoglycoproteins by hepatic binding protein was studied in freshly isolated hepatocytes from genetically diabetic BB Wistar rats. The number of cell surface asialoglycoprotein receptors was dramatically decreased (58,000±38,000 for diabetic rats compared to 267,000±70,000 for normal rats), while the association equilibrium constant was not changed. These results parallel those obtained with streptozotocin-diabetic rats and support the hypothesis that insulin deprivation is responsible for the decrease in the receptor number.     

Increase of collagen synthesis in pulmonary arteries of monocrotaline-treated rats

Summary Collagen synthesis in the pulmonary artery in animals with pulmonary hypertension was studied using monocrotaline-treated rats as a model. Incorporation of¹⁴C-labeled proline into collagenase-digestible protein in the pulmonary artery was found to be 4–5 times higher in monocrotaline-treated rats than in control rats.     

Carcinogenicity examination of betel nuts and piper betel leaves.

A dry powder of betel nuts, piper betel leaves and lime was administered to rats. Epidermal thickening was frequently observed in the upper digestive tracts of rats in groups fed the betel nut diet mixed with lime and the betel leaves diet, and a forestomach papilloma was seen in 1 rat given betel leaves diet. These epidermal changes were scarcely seen in rats given either betel nut or normal diet alone.     

Carcinogenicity examination of betel nuts and piper betel leaves

Summary A dry powder of betel nuts, piper betel leaves and lime was administered to rats. Epidermal thickening was frequently observed in the upper digestive tracts of rats in groups fed the betel nut diet mixed with lime and the betel leaves diet, and a forestomach papilloma was seen in 1 rat given betel leaves diet. These epidermal changes were scarcely seen in rats given either betel nut or normal diet alone.This work was supported by a grant from the U.S.-Japan Cooperative Medical Science Program     

A follow-up electrophysiological study of rats with poor intrauterine fetal growth: the development of visual evoked responses (VERs)

Summary The development of some electrophysiological activities of the visual system (VERs) was compared in control rats and in young rats with poor intrauterine fetal growth caused by an electrolytic lesion of the placenta. Treated rats showed a delayed development of the electrophysiological functions considered, thus confirming the postnatal effect of poor intrauterine fetal growth.This research was supported by grants of CNR and Ministero Pubblica Istruzione.     

Experimental liver fibrosis induced in rats receiving high doses of alcohol and alternating between regular and vitamin-depleted diets

Liver fibrosis was induced in rats by simulating human alcoholic eating and drinking patterns. Alcohol addiction was established by gradually increasing the ethanol concentration in the drinking water; salts were added at the terminal stage. The hepatocytes of rats receiving alcohol concentrations exceeding 50% (v/v) (similar to vodka) exhibited alcoholic hyaline (Mallory bodies). Alcoholic liver fibrosis was induced by alternating between regular and autoclaved (vitamin-depleted) diets, simulating the irregular eating habits of human alcoholics. In the livers of rats receiving 70% (v/v) ethanol (comparable to absinthe) with 25% saline and fed the alternating diets, pericellular fibrosis was induced. No significant difference in calorie intake between control and alcohol rats was detected except when rats underwent drinking bouts (heavy drinking phase). This indicates that neither a high-fat diet nor a choline-depleted diet is necessary to induce the alcoholic fibrosis seen in human alcoholics.     

Changes with hypertension and maturation in the response of stomach fundus to acetylcholine

The purpose of these experiments was to compare the contractile response to ACh of stomach fundal strips from hypertensive (SHR) and normotensive (WKY) rats during the development of hypertension. The results indicate that the reactivity to ACh is the same in fundal strips from young SHR and WKY rats; however, with maturation strips from WKY rats undergo a reduction in responsiveness which does not occur in the SHR. Therefore, strips from older SHR rats are more reactive to ACh than are those from age matched WKY rats.     

Influence of light on the plasma gonadotropin concentrations in the newborn rat.

The physiological increase in plasma gonadotropin (LH and FSH) levels in newborn rats is indisputably influenced by light. Permanent illumination accentuates this increase, whereas darkness decreases it in 16-day-old female rats. In male rats of the same age, only permanent illumination was tested with the same results.     

Changes with hypertension and maturation in the response of stomach fundus to acetylcholine

Summary The purpose of these experiments was to compare the contractile response to ACh of stomach fundal strips from hypertensive (SHR) and normotensive (WKY) rats during the development of hypertension. The results indicate that the reactivity to ACh is the same in fundal strips from young SHR and WKY rats; however, with maturation strips from WKY rats undergo a reduction in responsiveness which does not occur in the SHR. Therefore, strips from older SHR rats are more reactive to ACh than are those from age matched WKY rats.Acknowledgment. The authors wish to acknowledge the assistance of Mark Kunneman and Elaine Hughes. This work was supported by the following grants: American Heart Association (Texas Affiliate) and National Institutes of Health HL 23815, HL 25349 and HL 24585.     

Genetic and histological aspects of stomach lesions induced by systemic injection of phenylbutazone in the rat

Roman high-avoidance (RHA/Verh) rats, food-deprived (F-D) for 5 days, had higher stomach lesion scores than did F-D Roman low-avoidance (RLA/Verh) rats. F-D RLA/Verh rats which were injected i.p. with phenylbutazone (PBZ) 24 h before examination, however, had higher scores than did PBZ-treated, F-D RHA/Verh rats. Histologically, extensive edema and cellular infiltration (including numerous erythrocytes) were seen below the lesions, in the submucosa, denoting vascular damage. An attenuating influence of food on the ulcerogenic effects of PBZ, which were much more severe in F-D than in fed rats, was also indicated.     

Effect of chronic alloxan diabetes and insulin treatment on adipose tissue lipid composition of rats

Summary Decreased content of the adipose tissue lipids was observed in chronic alloxan diabetic rats and was restored to normal with insulin treatment. Prolonged insulin treatment in normal rats also resulted in increase of the lipid content of the adipose tissue.