Biomedical subjects

C Treves

Publications and source records attributed to C Treves.

At least 19 recordsLinked to original sources

PubMed2007

Biocompatibility evaluation of surface-treated AISI 316L austenitic stainless steel in human cell cultures.

The effects of AISI 316L austenitic stainless steel, tested in untreated state or subjected to glow-discharge nitriding (at 10 or 20 hPa) and nitriding + post-oxidizing treatments, on human umbilical vein endothelial cells (HUVEC) and on peripheral blood mononuclear cells (PBMC) were evaluated. All the treated samples showed a better corrosion resistance in PBS and higher surface hardness in comparison with the untreated alloy. In HUVEC put in contact for 72 h with the sample types, proliferation and apoptosis decreased and increased, respectively, in the presence of the nitrided + post-oxidized samples, while only slight differences in cytokine (TNF-alpha, IL-6, and TGF-beta1) release were registered. Intercellular adhesion molecule-1 (ICAM-1) increased in HUVEC incubated with all the treated samples, while vascular cell adhesion molecule-1 (VCAM-1) and E-selectin increased in the presence of all the sample types. PBMC incubated for 48 h with the samples showed a decrease in proliferation and an increase in apoptosis in the presence of the untreated samples and the nitrided + post-oxidized ones. All the sample types induced a remarkable increase in TNF-alpha and IL-6 release in PBMC culture medium, while only the untreated sample and the nitrided at 10 hPa induced an increase in ICAM-1 expression. In HUVEC cocultured with PBMC, previously put in contact with the treated AISI 316L samples, increased levels of ICAM-1 were detected. In HUVEC coincubated with the culture medium of PBMC, previously put in contact with the samples under study, a noteworthy increase in ICAM-1, VCAM-1, and E-selectin levels was always registered, with the exception of VCAM-1, which was not affected by the untreated sample. In conclusion, even if the treated samples do not show a marked increase in biocompatibility in comparison with the untreated alloy, their higher corrosion resistance may suggest a better performance as the contact with physiological environment becomes longer.

Biocompatible Materials↗

PubMed2001

Suppressive effect of 1,25-dihydroxyvitamin D3 and its analogues EB 1089 and KH 1060 on T lymphocyte proliferation in active ulcerative colitis.

This study examined the effect exerted by 1,25-dihydroxyvitamin D3 [1,25(OH)2D3] and two vitamin D analogues, EB 1089 and KH 1060, on the proliferation of T lymphocytes obtained from ulcerative colitis (UC) patients and healthy controls. The proliferative response of T lymphocytes to phytohaemagglutinin treatment was first analyzed on days three, five, and seven of culture. Cell proliferation was significantly lower in UC patients than that observed in healthy controls. The highest proliferation value, in either controls or patients, was registered on day five of culture. On day seven, a decrease in proliferation occurred, less evident in patients with respect to controls, whereas on day three, controls and patients showed the same proliferation value. The response of T lymphocytes of either healthy controls or UC patients to 1,25(OH)2D3, EB 1089, or KH 1060 was then investigated, treating the cells for three, five, and seven days with 10 nM vitamin D derivatives. In the presence of these compounds, cell proliferation was significantly inhibited in both groups, but on day seven, the inhibition of lymphocyte proliferation was remarkable in controls, whereas in patients it was similar to that registered on day five. The highest inhibition values were always obtained in the presence of KH 1060, and the time dependence was continuous in controls, but in the presence of EB 1089 only in patients. T lymphocytes prepared from healthy controls and UC patients were then cultured for five days in the presence of vitamin D derivatives at three different concentrations (0.1, 1, and 10 nM). In the two groups, a dose-dependent inhibition was registered in the presence of 1,25(OH)2D3 or EB 1089, while the inhibition of proliferation exerted by KH 1060 was not dose-dependent. The results obtained suggest an option for the use of the two non-hypercalcemic vitamin D analogues in the therapy of UC patients, perhaps in association with other immunosuppressive drugs.

Adult↗

PubMed2001

Synergistic anti-proliferative effects of vitamin D derivatives and 9-cis retinoic acid in SH-SY5Y human neuroblastoma cells.

This study examines the effect of 1,25-dihydroxyvitamin D(3) [1,25(OH)(2)D(3)], 24,25-dihydroxyvitamin D(3) [24,25(OH)(2)D(3)], two vitamin D analogues (KH 1060 and EB 1089, which are 20-epi-22-oxa and 22,24-diene-analogues, respectively), 9-cis retinoic acid and all-trans retinoic acid on proliferation of SH-SY5Y human neuroblastoma cells, after treatment for 7 days. Cell number did not change when the cells were incubated with 1, 10 or 100 nM 1,25(OH)(2)D(3) or its derivatives, but significantly decreased in the presence of the two retinoids (0.001--10 microM final concentration). A synergistic inhibition was observed, when SH-SY5Y cells were treated combining 0.1 microM 9-cis retinoic acid and 10 nM 1,25(OH)(2)D(3) or 10 nM KH 1060, and 1 microM 9-cis retinoic acid and 10 nM 1,25(OH)(2)D(3) or 10 nM EB 1089. Acetylcholinesterase activity showed a significant increase, in comparison with controls, after treatment of the cells for 7 days with 0.1 or 1 microM 9-cis retinoic acid, alone or combined with 10 nM 1,25(OH)(2)D(3) or 10 nM KH 1060 or 10 nM EB 1089. This increase was synergistic, combining 1 microM 9-cis retinoic acid and 10 nM 1,25(OH)(2)D(3) or EB 1089. The levels of the c-myc encoded protein remarkably decreased after treatment of SH-SY5Y cells for 1, 3, 7 days with 0.1 and 1 microM 9-cis retinoic acid, alone or combined with 10 nM 1,25(OH)(2)D(3) or 10 nM KH 1060 or 10 nM EB 1089. In particular, the association of 1 microM 9-cis retinoic acid and 10 nM 1,25(OH)(2)D(3) or 10 nM EB 1089 resulted in a synergistic c-myc inhibition, in comparison with that obtained in the presence of the retinoid alone. These findings may have therapeutic implications in human neuroblastoma.

Acetylcholinesterase↗

PubMed1999

Vitamin D receptor in SH-SY5Y human neuroblastoma cells and effect of 1,25-dihydroxyvitamin D3 on cellular proliferation.

This study examines the effect of 1,25-dihydroxyvitamin D3 [1,25(OH)2D3] on proliferation of SH-SY5Y human neuroblastoma cells and demonstrates, for the first time, the presence of vitamin D receptor (VDR) in this cell line. Cell number showed a significant decrease, when the cells were incubated with 1 or 10 nM 1,25(OH)2D3 for 24, 48, 72, 96 and 144 h, while 100 nM 1,25(OH)2D3 was ineffective after 24 and 96 h incubation. The highest inhibition (about 35%) was observed after 72 h treatment with the hormone at the three concentrations used. Protein content per cell increased, in comparison with controls, after treatment of SH-SY5Y neuroblastoma cells with 1,25(OH)2D3, at the three concentrations, up to 96 h incubation. 1, 10 or 100 nM 1,25(OH)2D3 positively affected [3H]thymidine incorporation after treatment of the cells for 48 and 72 h, while, after 24 h, only 10 nM 1,25(OH)2D3 exerted a stimulatory action. To study the expression of the VDR gene, Northern blot analysis was performed. Subconfluent SH-SY5Y neuroblastoma cells were treated for 24 h with medium containing 10 nM 1,25(OH)2D3 or vehicle alone. A main transcript of an approximate size of 4.5 kb, present either in controls or in cells incubated with the hormone, was revealed. A limited increase in VDR mRNA levels was observed in the cells treated with 1,25(OH)2D3, fetal bovine serum or forskolin. Only slight differences in morphology were perceived between SH-SY5Y cultures maintained with or without 10 nM 1,25(OH)2D3 for 7 days.

Calcitriol↗

PubMed1999

Role of 1,25-dihydroxyvitamin D3 and extracellular calcium in the regulation of proliferation in cultured SH-SY5Y human neuroblastoma cells.

This study examines the effects of 1,25-dihydroxyvitamin D3 [1,25(OH)2D3] on SH-SYSY human neuroblastoma cells cultured in the presence of medium containing varying concentrations of calcium (0.1, 0.9, 1.4, 1.8 mM). Pyruvate kinase activity was assayed in SH-SY5Y cells incubated in variable calcium medium with or without 1, 10 or 100 nM 1,25(OH)2D3 for 48 h. The enzyme levels showed a significant increase in comparison with control, when the cells were incubated with 100 nM hormone in the presence of 0.1 mM calcium, while pyruvate kinase activity decreased, when the cells were treated with 100 nM 1,25(OH)2D3 in the presence of 1.8 mM calcium. The proliferative activity of SH-SY5Y was dependent on the extracellular concentration of calcium, being the highest at 1.8 mM calcium and completely absent at 0.1 mM calcium. In the presence of 1,25(OH)2D3, at the three concentrations used and after 48 h incubation, a significant decrease in cell number was always observed, without a direct correlation between 1,25(OH)2D3 effect and calcium concentration in the medium. [3H]Thymidine incorporation in SH-SY5Y cells significantly increased in comparison with control, when the 48 h incubation with 1, 10 or 100 nM 1,25(OH)2D3 was carried out in the presence of 0.1 mM calcium, while, at the other calcium concentrations, the hormone did not cause any significant change in this parameter. The treatment of SH-SYSY cells with 1 nM 1,25(OH)2D3 for 48 h did not affect cell morphology, when 0.1 mM calcium was present, while, in the medium containing 1.8 mM calcium, the treated cells showed a slight trend to differentiation. The differentiating effect of 10 microM all-trans retinoic acid, even if incomplete after 48 h treatment, was only observed in the cultures grown in 1.8 mM calcium, in comparison with those maintained in 0.1 mM calcium.

Calcitriol↗

PubMed1997

Vitamin D receptor in IMR-90 human fibroblasts and antiproliferative effect of 1,25-dihydroxyvitamin D3.

This study examines the effect of 1,25-dihydroxyvitamin D3 [1,25(OH)2D3], serum or forskolin on the proliferation of IMR-90 fetal lung fibroblasts and demonstrates, for the first time, the presence of 1,25(OH)2D3 receptor (VDR) in this cell line. In quiescent, subconfluent cultures neither the treatment with 100 nM 1,25(OH)2D3 nor that with 50 microM forskolin influenced proliferation, while a significant increase was observed after incubation of the cells with 10% fetal bovine serum. Either cell number, determined on growing IMR-90 human fibroblasts after 48 or 72 h incubation with 100 nM 1,25(OH)2D3 or [3H]thymidine incorporation (24, 48 or 72 h incubation) significantly decreased, while protein content per cell increased. Northern blot analysis revealed the expression of the VDR gene, the VDR mRNA bands being prominent in 1,25(OH)2D3, serum or forskolin treated fibroblasts. VDR mRNA levels slightly decreased, when growing fibroblasts were exposed to 100 nM 1,25(OH)2D3 for 48 or 72 h.

Animals↗

PubMed1996

Effect of 1,25-dihydroxyvitamin D3 on proliferation in senescent IMR-90 human fibroblasts.

The response of IMR-90 human fetal lung fibroblasts at high population doubling level (PDL > 42) to 1,25-dihydroxyvitamin D3[1,25(OH)2D3] was investigated to clarify whether some metabolic and molecular parameters of senescent cells are affected by the hormone treatment. Pyruvate kinase, lactate dehydrogenase and glucose-6-phosphate dehydrogenase activity significantly increased after treatment of confluent-phase cells with 10 nM 1,25(OH)2D3 for 24 h. Steroid specificity was established by the failure of 10 nM levels of 25-hydroxyvitamin D3 to affect the enzyme activities, while estradiol-17 beta and progesterone produced a slight increase in glucose-6-phosphate dehydrogenase and lactate dehydrogenase levels, respectively. 1,25(OH)2D3 also affected fibroblast proliferation, protein content/cell and DNA synthesis. The cell number significantly decreased after a 48 h incubation with 1,25(OH)2D3 at various concentrations (0.01-1 nM) when compared with control fibroblasts, while an increase in the protein content/cell was demonstrated. The same experiment, carried out by protracting the incubation with the hormone for 72 h, showed a similar trend, but 10 nM 1,25(OH)2D3 was also able to inhibit cell proliferation and to stimulate protein synthesis. The incorporation of [3H]thymidine into DNA increased after the treatment of high PDL fibroblasts with 0.01-1 nM of hormone for 48 h in comparison with controls.

Aging↗

PubMed1995

1,25-dihydroxyvitamin D3 inhibits proliferation of IMR-90 human fibroblasts and stimulates pyruvate kinase activity in confluent-phase cells.

This study tested the hypothesis that 1,25-dihydroxyvitamin D3 (1,25(OH)2D3) plays a role in regulating some aspects of metabolism in IMR-90 normal human fetal lung fibroblasts. Among the enzymes studied, only pyruvate kinase showed a significant increase after treatment of confluent-phase cells with 1,25(OH)2D3 at various concentrations (0.1-100 nM range) for 24 h. A parallel increase in lactate output was observed. Steroid specificity was established by the failure of 10 nM levels of 25-hydroxyvitamin D3, estradiol-17 beta and progesterone to affect pyruvate kinase activity. The determination of the time course of [3H]-2-deoxy-D-glucose transport indicated that the hormone did not influence the transmembrane transport system of D-glucose. The addition of the inhibitors cycloheximide and actinomycin D to the culture medium abolished, at least in part, the 1,25(OH)2D3 stimulation of pyruvate kinase activity, suggesting the probable dependence of the hormone effect on cellular RNA and protein synthesis. 1,25(OH)2D3 also affected fibroblast growth and DNA synthesis. Cell number significantly decreased after 2-5 days treatment with 10 nM hormone in comparison with control fibroblasts, and also the incorporation of [3H]thymidine into DNA decreased after treatment of the cells with 1 and 10 nM hormone for 48 h. In conclusion, these data demonstrate that 1,25(OH)2D3 stimulates pyruvate kinase activity in confluent-phase IMR-90 human fibroblasts by a mechanism probably dependent on de novo protein synthesis, and also affects cell growth and DNA synthesis in sub-confluent-phase cells.

Biological Transport↗

PubMed1995

Vitamin D--related modification of enzyme activities in synaptosomes and mitochondria isolated from rat cerebral cortex.

We previously demonstrated that feeding rats the Steenbock and Black rickets-inducing diet produces remarkable changes in the metabolic pattern of intestinal mucosa, kidney, liver, cerebral cortex and heart. We have now determined the levels of calcium, phosphorus and citrate in cerebral cortex and the activity of some enzymes in synaptosomes and cerebral cortex mitochondria of three rat groups: control (Group A), fed a vitamin D-deficient diet (Group B), fed a vitamin D-deficient diet and treated with 1,25-dihydroxyvitamin D3 (Group C). While calcium content increased in Groups B and C, phosphorus concentration increased only in Group C and citrate in Group B in comparison with control. The increase in acetylcholinesterase and citrate synthase registered in Group B was restored to control values by 1,25-dihydroxyvitamin D3 treatment, while, neither the decrease in cytochrome c oxidase, nor the increase in glucose-6-phosphate dehydrogenase, acid phosphatase and NADP+(-)isocitrate dehydrogenase observed in Group B were corrected by 1,25-dihydroxyvitamin D3 supply. Acyl phosphatase showed a remarkable increase in consequence of 1,25-dihydroxyvitamin D3 administration.

Animals↗

PubMed1994

Effect of vitamin D deficiency and 1,25-dihydroxyvitamin D3 on rat heart metabolism.

The purpose of this study was to investigate whether vitamin D3 deficiency and 1,25-dihydroxyvitamin D3 treatment affect some aspects of heart metabolism in the rat. To this end, five experimental groups were studied: (1) the control group of the vitamin D3 supplemented rats (Group A); (2) rachitic rats (Group B); (3) rachitic rats treated with 1,25-dihydroxyvitamin D3 (Group C); (4) rats fed a vitamin D-deficient diet (Group D); (5) rats fed a vitamin D-deficient diet and treated with 1,25-dihydroxyvitamin D3 (Group E). The five groups were compared by checking in the heart some metabolic parameters, i.e. citrate content, and enzyme activities in cytosol and mitochondria. Citrate content was higher in the heart of treated animals when compared with the control. As regards the enzymatic activities in heart mitochondria, NAD(+)-dependent isocitrate dehydrogenase remarkably decreased in Group B rats and 1,25-dihydroxyvitamin D3 restored quite normal values. NADP(+)-dependent isocitrate dehydrogenase decreased in Group B and Group D animals, and 1,25-dihydroxyvitamin D3 treatment was effective in restoring control values. Cytochrome c oxidase activity did not change, while citrate synthase showed an increase in all the treated rats. As regards the cytosolic enzymes, fructose-6-phosphate kinase increased in the two groups of vitamin D-deplete rats in comparison with the control. Glyceraldehyde-3-phosphate dehydrogenase and 3-phosphoglycerate kinase showed a similar trend: an increase in all the treated animals. In heart homogenate, acylphosphatase and acid phosphatase activities were also determined. Acylphosphatase increased in the treated rats, while acid phosphatase decreased in the rats injected with 1,25-dihydroxyvitamin D3. These results support the hypothesis of a participation of 1,25-dihydroxyvitamin D3 in some aspects of heart metabolism.

Animals↗

PubMed1993

Effect of vitamin D deficiency and 1,25-dihydroxyvitamin D3 on metabolism and D-glucose transport in rat cerebral cortex.

We previously demonstrated that feeding rats Steenbock and Black's rickets-inducing diet produces remarkable changes in the metabolic pattern of the intestinal mucosa, kidney, and liver and in some membrane transport systems of intestinal mucosa and kidney. 1,25-Dihydroxyvitamin D3 administration to rachitic rats did not always prove to be effective in restoring normal values. We have now investigated the effect of 1,25-dihydroxyvitamin D3 on the levels of some metabolites in rat cerebral cortex, on the activity of some enzymes, and on the transport of 2-deoxy-D-glucose and D-glucose in synaptosomes. Our experiments were carried out on three rat groups: control, rachitic, and rachitic treated with 1,25-dihydroxyvitamin D3. The decrease in phosphorus content and the increase in citrate concentration observed in rachitic rat cerebral cortex were corrected by 1,25-dihydroxyvitamin D3 treatment. The activity of acetylcholinesterase, glucose-6-phosphate dehydrogenase, and acyl phosphatase significantly increased in rachitic rat synaptosomes, as well as NAD(+)-dependent isocitrate dehydrogenase in cerebral cortex mitochondria; the administration of 1,25-dihydroxyvitamin D3 to rachitic rats restored enzyme levels to normal. The transport of 2-deoxy-D-glucose and D-glucose in rachitic rat synaptosomes was lower than in the control group and returned to control values in consequence of 1,25-dihydroxyvitamin D3 treatment. The results reported here support the hypothesis of a participation of 1,25-dihydroxyvitamin D3 in some aspects of cerebral cortex metabolism.

Acetylcholinesterase↗

PubMed1993

Age and GSH metabolism in rat cerebral cortex, as related to oxidative and energy parameters.

A comprehensive study on GSH metabolism in relation to some markers of oxidative and energy status in rat cerebral cortex as a function of age was performed. Reduced GSH, total GSH and the GSH Redox Index decreased both during growth (defined as the period between 1 and 5 months) and during aging (defined as the period between 5 and 27 months) while GSSG levels increased during the two periods, but most significantly during aging. Also GSH-associated enzymes and adenine-pyridine nucleotide levels show age characteristic changes. The obtained results suggest that decreases in oxidative and energy metabolism occur during aging. They probably contribute to decreases in the activity of the biosynthetic processes (i.e., NADP+(H) and GSH synthesis) and in the antioxidant capacity of the GSH system. However, the oxidative stress does not seem to be a typical characteristic of the aging period; as an oxidative status is present during the growth period too. Typical parameters of aging process are mainly the low levels of reduced GSH, total GSH and GSH Redox Index and the high levels of GSSG as well as the high levels of GSH peroxidase and GSH transferase and the low levels of gamma-glutamylcysteine synthetase.

Adenosine Diphosphate↗

PubMed1991

Effect of vitamin D deficiency on D-glucose and citrate transport in rat renal basolateral membrane vesicles.

We had previously reported that feeding rats on Steenbock and Black's rickets-inducing diet markedly influences the metabolic picture of the kidney and the transmembrane transport systems of D-glucose and citrate in renal brush-border membrane vesicles. We have now studied D-glucose and citrate transport into basolateral membrane vesicles prepared from kidney cortex of control and rachitic rats and the effect of 1,25-dihydroxyvitamin D3 on these transport systems was also investigated. D-glucose and citrate uptake, determined in the presence of a Na(+)-gradient, was lowered in rachitic animals and 1,25-dihydroxyvitamin D3 administration proved to be ineffective in restoring normal values. Citrate transport, determined in the presence of a K(+)-gradient, was not influenced by both rickets and 1,25-dihydroxyvitamin D3 supply. The in vitro addition to vesicle preparations of calcium or phosphate or citrate or 1,25-dihydroxyvitamin D3 did not show a selective influence on D-glucose and citrate uptake.

Animals↗

PubMed1990

Changes in metabolite transport by small intestine and kidney of young and old rats.

We have studied the influence of the ageing phenomenon on metabolite absorption by the small intestine and the kidney of the rat, using isolated brush-border membrane vesicles prepared from 2 groups, one composed of 2 month, and the other of 24 month, animals. "Overshoot", which is typical of Na(+)-glucose cotransporter activity, disappeared in the duodenum and decreased in the kidney of the old rats. Short-circuiting of vesicles with valinomycin showed that, in the presence of K+ and valinomycin, "overshoot" decreased in both groups by about the same percentage. The Na(+)-dependent uptake of aspartate and phenylalanine showed contrasting pictures in the jejunum and kidney of the aged animals: aspartate transport decreased only in the kidney, while phenylalanine uptake was negatively affected in the jejunum. Na(+)-dependent citrate uptake, studied in renal brush-border membrane vesicles, was lower in the old rats. The Km values determined for Na(+)-dependent D-glucose and citrate uptake in the kidney did not meaningfully differ between the two groups. A continuous decrease in Na(+)-dependent D-glucose and citrate uptake in the rat kidney, during ageing, was demonstrated.

Aging↗

PubMed1989

Glucose transport during ageing by human intestinal brush-border membrane vesicles.

Glucose absorption by the small intestine is a complex phenomenon, that can be successfully studied by means of isolated brush-border and basolateral membrane vesicles of the enterocytes. We have carried out transport experiments on isolated brush-border membrane vesicles from the human small intestine, taking into account the age of the subjects. Our studies demonstrated that Na+-glucose cotransporter activity decreased as age increased with the "overshoot" phenomenon disappearing altogether in the oldest subjects. This effect was compared to that observed in intestinal membrane vesicles of young patients suffering from Crohn's disease; in this case there was a marked decrease in the Na+-dependent D-glucose uptake, but the "overshoot", even though low, was present. K+-dependent D-glucose transport, diffusion of L-glucose and the levels of some enzyme markers for intestinal brush-border membranes were also studied.

Adult↗

PubMed1989

[Influence of a rachitogenic regime on hepatic metabolism in the rat].

We have previously reported that rats fed on the Steenbock and Black's rickets-inducing diet (deficient in vitamin D and with an altered Ca/P ratio) show metabolic modifications in kidney and intestinal mucosa. We have therefore decided to investigate if also in liver, seat of vitamin D hydroxylation, changes in the metabolic pattern occur. An increase of mitochondrial NAD+-dependent isocitrate dehydrogenase and a decrease of citrate and ATP content was demonstrated in liver of rachitic rats, together with changes in ATP-citrate lyase and glucose-6-phosphate dehydrogenase activity. The inhibitory effect of ATP on liver mitochondria NAD+-dependent isocitrate dehydrogenase was also studied.

ATP Citrate (pro-S)-Lyase↗

PubMed1988

[Effect of natural or synthetic detergents on the transport of D-glucose in the membranes of vesicles of the brush border of the intestine of the rabbit].

We describe here the effects of natural and synthetic detergents on the D-glucose transport into brush-border membranes of vesicles of rabbit's intestine. Two synthetic detergents: Triton X-100 and dodecyltrimethylammonium bromide have been found very strong inhibitors (more than 50 p. 100 of inhibition of maximal D-glucose uptake). Kinetic studies showed that these detergents behaved as mixed type inhibitors. The Na+-dependent transport of amino acids (aspartic acid, lysine, phenylalanine) is only poorly affected by dodecyltrimethylammonium bromide, while Triton X-100 inhibits unspecifically all the transport studied.

Animals↗

PubMed1988

Effect of 25-hydroxyvitamin D3 on Na+-dependent D-glucose transport in rachitic rats.

We have previously reported that feeding rats on Steenbock and Black's rickets-inducing diet, deficient in vitamin D and with an altered Ca/P ratio, leads to metabolic consequences and a marked decrease of Na+-dependent D-glucose uptake at the jejunum-ileum level. To clarify the relationship between experimental rickets and D-glucose uptake, 25-hydroxyvitamin D3 (25-OH-D3) was given to rats fed on the rickets inducing diet. In the jejunum-ileum of these animals Na+-dependent D-glucose uptake returned to the values of the controls while the decrease in D-glucose uptake in the brush-border membrane vesicles prepared from kidney cortex of rachitic animals was not corrected by the administration of 25-OH-D3.

Animals↗