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J C Basabe

Publications and source records attributed to J C Basabe.

At least 19 recordsLinked to original sources
PubMed2005

Effect of troglitazone on the desaturases in a rat model of insulin-resistance induced by a sucrose-rich diet.

A sucrose-rich diet generates time-dependent metabolic disorders similar to those found in diabetes type 2. After 8 month (mo) this diet evoked in the rat an increase of blood glucose, free fatty acids (FFA) and triacylycerides (TG) without insulin modification, an interruption of liver stearoyl-CoA desaturase-1 (SCD-1) mRNA and activity increase found at 6 mo, and an enhacement of Delta6 and Delta5 desaturase mRNA and Delta6 activity. We found that the administration of troglitazone (TRO), a peroxisome-proliferator-activated receptors gamma (PPAR-gamma) agonist, for 2 mo normalized plasma FFA, TG, and glucose without altering the insulinemia. It depressed liver SCD-1 mRNA in both control and sucrose-fed rats, decreasing the 18:1n-9/18:0 ratio in serum and liver lipids, and eliminated the increasing effect on mRNA and activity of Delta6 and Delta5 desaturases. These findings evidence again that desaturases are not affected through an insulin resistant effect evoked by the sucrose-rich diet and TRO recovers the altered metabolic plasma parameters as it corresponds to a PPAR-gamma agonist, but its effect on hepatic desaturases can not be attributed to a direct action on liver by PPAR-gamma, insulin, and even by an insulin sensitizing mechanism, suggesting it would be evoked indirectly through hepatic PPAR-alpha deactivation induced by the FFA decrease.

Animals↗
PubMed2001

Effect of modified diabetic splenocytes on mice injected with splenocytes from multiple low-dose streptozotocin diabetic donors.

Etiological agents of autoimmune processes that have been made nonvirulent by several treatments, i.e., mitomycin C (Mit C), can be used as a vaccine to protect against disease. In this work we studied the effects of splenocytes from diabetic mice on animals that had been injected with modified splenocytes (Mit C-treated splenocytes from multiple low-dose streptozotocin [mld-sz] mice) 15 days before. Splenocytes from mld-sz diabetic donors altered i.p. glucose tolerance and the first peak of insulin secretion pattern when injected into normal singeneic recipients. These effects can be prevented partially (one injection in a vaccine form) or completely (two injections with a 15-day interval) by a previous injection of Mit C-treated mononuclear splenocytes (MS) from mld-sz mice. The fact that control splenocytes previously treated with Mit C were not able to achieve similar results indicates that donor splenocytes have to be diabetic to prevent the disease. On the other hand, Mit C-treated diabetic MS were not effective in preventing the alterations in glucose tolerance and in the pattern of insulin secretion when injected into athymic mice. This suggests that the preventive effect of Mit C-treated diabetic MS injection also implies an active role of the T cells from the recipient mice. Mit C-treated diabetic splenocytes are preferentially trapped by the pancreas and the lymph nodes from recipient mice. Our results show that the impairment in glucose tolerance and in the insulin secretion pattern produced by diabetic splenocyte transfer can be prevented by one or two previous injections of Mit C-modified diabetic splenocytes.

Animals↗
PubMed2000

Branched-chain amino acid-enriched diet: effects on insulin secretion and cellular immune aggression.

Several reports have demonstrated that high-protein diets may have beneficial effects on experimental models of diabetes and have raised the possibility that branched-chain amino acids could play a role in these protective effects. We investigated the effect of a normoproteic, branched-chain amino acid-enriched diet (experimental diet) on insulin secretion from C57BL/6N mice transferred with splenocytes from diabetic syngeneic donors. Mice previously fed with the experimental or control diet received three intraperitoneal injections, every other day, of 5 x 107 viable mononuclear splenocytes obtained from control or diabetic donors. Results showed that mice fed with the experimental diet and transferred with "diabetic" splenocytes presented: i) normoglycemia, and (ii) significantly higher levels in both phases of glucose-induced insulin secretion and normal values of arginine-glucose-induced insulin secretion. To evaluate the in vitro cellular immune aggression, dispersed mouse islet cells were co-cultured with splenocytes from syngeneic diabetic mice. First, dispersed islet cells from mice on the experimental or control diet were co-cultured with splenocytes from control or diabetic mice on a commercial diet. In the presence of "diabetic splenocytes, dispersed islet cells from mice on the experimental diet presented a significantly lower in vitro cellular immune aggression. On the other hand, "diabetic" splenocytes from mice fed with the experimental diet produced a significantly reduced cellular immune aggression on dispersed islet cells. Our results showed that feeding branched-chain amino acids increased the capacity of beta cells to withstand a functional assault and diminished the extent of in vitro cellular immune aggression.

Amino Acids, Branched-Chain↗
PubMed2000

Troglitazone (CS-045) normalizes hypertriglyceridemia and restores the altered patterns of glucose-stimulated insulin secretion in dyslipidemic rats.

Rats fed a sucrose-rich diet ([SRD] 63% wt/wt) up to 270 days develop stable hypertriglyceridemia, impaired glucose tolerance, and insulin insensitivity. The aim of the present study is to investigate whether the hypoglycemic agent troglitazone introduced as a pharmacologic intervention could improve and/or reverse the whole-body insulin insensitivity and related abnormalities present after feeding normal rats with a SRD long-term. For this purpose, male Wistar rats were fed a SRD for 210 days. While half of the animals continued with this diet for up to 270 days, troglitazone (0.2 g/dL wt/wt) was added to the SRD of the other half for up to 270 days. Troglitazone markedly reduced in vivo the hepatic triglyceride secretion rate (TGSR) and enhanced its removal from the circulation, leading to a normalization of plasma triglyceride levels. It also normalized the whole-body peripheral insulin resistance, the glucose homeostasis, and the elevated free fatty acids (FFAs) without detectable changes in plasma insulin levels. The clear alteration of the biphasic pattern of glucose-stimulated insulin secretion in the in vitro perfused beta-cell islets of rats fed the SRD long-term (270 days) was also completely normalized when the SRD was supplemented with troglitazone for 2 months. The normalization of the altered patterns of glucose-stimulated insulin secretion, as well as the enhancement of peripheral insulin sensitivity without detectable changes in plasma insulin, might be largely a result of the significant action of troglitazone in the decrease of circulating lipids and enhancement of whole-body glucose metabolism.

Animals↗
PubMed1996

Inhibition of nitric oxide generation: normalization of in vitro insulin secretion in mice with multiple low-dose streptozotocin and in mice injected with mononuclear splenocytes from diabetic syngeneic donors.

We studied the effect on in vitro glucose-induced insulin secretion of in vivo administration of L-Ng-monomethyl-arginine (L-NMMA), a competitive inhibitor of nitric oxide (NO) synthase, to mice injected with multiple low-dose streptozotocin (mld-SZ). In addition, the effect of L-NMMA treatment on the capacity of mononuclear spleen cells (MS) from mld-SZ mice to transfer alterations in insulin secretion from normal syngeneic receptors was also investigated. We also studied the effect of in vivo treatment with L-NMMA on anti-beta-cell cellular immune aggression (CIA) by coculturing MS from mld-SZ mice with rat dispersed islet cells. Our results show that mld-SZ mice treated with 0.25 mg L-NMMA/g body weight had normoglycemia, first and second-phase glucose-stimulated insulin secretion similar to those obtained in nondiabetic mice-effects not observed with a lower dose of L-NMMA (0.17 mg/g body weight)-and a diminished anti-beta-cell CIA. We also demonstrate that mice injected with MS from syngeneic donors treated with mld-SZ plus 0.25 mg L-NMMA/g had normal levels for first-phase glucose-stimulated insulin secretion and an absence of CIA. Taken together, these findings seem to indicate that prevention of in vivo NO production may block the onset of diabetes in mld-SZ mice, and that L-NMMA administration to diabetic donor mice prevents inhibition of first-phase insulin secretion and CIA in the transferred recipient mice. Although a nonimmunological mechanism or mechanisms of diabetes prevention by L-NMMA cannot be excluded, these results suggest that L-NMMA treatment could also be acting on T-cell-dependent immune reactions.

Animals↗
PubMed1996

Effect of high-protein feeding on insulin secretion in mice injected with splenocytes from diabetic mice.

We report here our study of the in vitro glucose-induced insulin secretion from mice fed with a high-protein diet and injected with mononuclear splenocytes from streptozotocin-diabetic syngeneic donors. Results show that transfer of "diabetic" splenocytes caused significant diminutions in first phase of stimulated-insulin secretion. Nevertheless, insulin secretory levels attained in recipient mice fed with the high-protein diet were significantly higher than in mice fed with control diets. We also evaluated the effect of high-protein feeding on the capacity of "diabetic" splenocytes to transfer an impaired insulin secretion in recipient mice. For this purpose, splenocytes donor mice were fed with high-protein or control diets and injected with multiple low doses of streptozotocin. "Diabetic" splenocytes from high-protein, or control diets fed donors caused in recipient mice similar impairments in glucose-stimulated insulin secretion. Taken together, these results seem to support the hypothesis of a protective effect of a high-protein diet on the beta-cell function.

Animals↗
PubMed1996

[Autoimmune hypoglycemia syndrome with specific anti-human insulin antibodies].

A 33 year old woman with episodes of severe hypoglycemia is presented. The studies showed anti-insulin antibodies and variable C-peptide levels. Circulating insulin measured after acid-ethanol extraction, was of 1,600 uU/ml and shown to be human insulin after characterization by HLPC. Specific anti-human insulin antibodies were of high affinity (Ka1: 6.20 x 10(10) M-1; Ka2: 2.42 x 10(9) M-1). A small cross-reactive porcine and bovine antibody subpopulation was also detected (IgG, light k type chain). Plasmapheresis was undertaken when symptoms were spontaneously declining and turned antibody title negative. Prolonged follow-up showed no relapse of this syndrome.

Adult↗
PubMed1995

Insulin secretion by pancreas of athymic mice injected with peripheral mononuclear cells from insulin-dependent diabetic patients.

We studied the effect of peripheral blood mononuclear cells (PBMNC) from insulin-dependent diabetic (IDDM) children on the insulin secretion pattern of the pancreas from recipient athymic mice. PBMNC from healthy controls or IDDM patients in different stages of disease were injected into athymic mice. PBMNC from newly diagnosed IDDM children elicited basal nonfasting hyperglycemia and in vitro inhibition of the first and second phases of glucose-stimulated insulin secretion in recipient mice. Animals injected with cells from chronically IDDM children showed normoglycemia, abnormal tolerance to glucose, and inhibition of first-phase insulin secretion. Mitomycin C treatment of MNC from IDDM patients abolished insulin secretion inhibition in recipient mice. PBMNC from newly diagnosed and chronically IDDM patients showed positive anti-beta-cell cellular immune aggression. Mice injected with cells from patients during the remission period showed normoglycemia and no alteration of insulin secretion patterns. When relapsed to their former clinical stage, injection of the cells significantly inhibited first-phase glucose-induced insulin secretion in recipients. PBMNC from newly diagnosed IDDM patients were found to migrate to the pancreas of recipient mice preferably as compared with cells from controls. Cells from chronically IDDM patients cultured with concanavalin A (Con A) increased insulin secretion inhibition; despite this, cells from children during the remission period cultured with Con A failed to modify insulin secretion in recipients. These results show that injection of PBMNC from diabetic patients leads to insulin secretion impairment in recipient mice pancreas, and provide a basis for the study of mechanisms involved in the onset and modulation of anti-beta-cell cellular immune aggression induced by human PBMNC.

Adolescent↗
PubMed1994

Beta-cell function in mice injected with mononuclear splenocytes from multiple-dose streptozotocin diabetic mice.

Multiple low doses of streptozotocin (mid sz 40 mg/kg/day, five consecutive days) induce autoimmune diabetes in mice. The aim of the present work was to study beta-cell function in mice injected with splenocytes from mid-sz diabetic mice. Mononuclear splenocytes (MS) from control or diabetic donors were injected into syngeneic C57BL/6J healthy mice (5 x 10(7) MS, ip). MS from diabetic donors did not produce basal hyperglycemia, but they induced abnormal ip glucose tolerance in recipient mice. These "diabetic" MS were also preferentially trapped by the recipient's pancreas. Perifused pancreas from mice injected with MS from mid sz-diabetic donors showed a diminished first and second phase of glucose-induced insulin secretion after 15 days of the cell injection. At this time, pancreatic insulin content among MS recipients did not differ from that found in controls or diabetic donors. Diabetic MS treated with Mitomycin C prior to transfer did not inhibit insulin secretion in recipient mice. Injection of MS from mice made diabetic by a single high sz dose (200 mg/kg) did not induce any alterations of the insulin secretion in recipients. There is enough evidence when using athymic and euthymic (BALB/c nu/nu and +/nu) mice to suggest that proliferation of the injected splenocytes enhanced the progression to the diabetic state, and that both donor and recipient T lymphocytes played an important part in this progression. The results suggest that injection of MS from mid sz-diabetic mice interfere with glucose-stimulated insulin secretion in recipient mice and provide a basis for the study of the mechanisms involved in the onset and modulation of autoimmune pancreatic aggression.

Animals↗
PubMed1992

Cellular and humoural autoimmunity markers in type 2 (non-insulin-dependent) diabetic patients with secondary drug failure.

In some cases patients with Type 2 (non-insulin-dependent) diabetes mellitus fail to respond to treatment with oral hypoglycaemic agents. These patients may respond in the same way as Type 1 (insulin-dependent) diabetic patients. Cellular immune aggression (defined as the capacity of peripheral mononuclear cells to inhibit stimulated insulin secretion by dispersed rat islet cells), insulin autoantibodies, C-peptide response and HLA antigens were determined in 31 Type 2 diabetic patients with secondary failure to oral hypoglycaemic agents and in 22 control subjects. Nine (29.03%) of the 31 Type 2 diabetic patients showed positive cellular immune aggression (2 SD below control group) and 22 (70.97%) presented no cellular immune aggression. There was a relationship between positive cellular immune aggression and each of the following parameters: age, body mass index and microangiopathy. No correlation was found between positive cellular immune aggression and glycaemia, HbA1, blood lipids or atherosclerosis. Patients with positive cellular immune aggression showed a significantly lower glucagon-stimulated C-peptide response vs those with no cellular immune aggression. Within a sub-group of patients who had never been treated with insulin, insulin autoantibodies were present in four of six patients with positive cellular immune aggression. DR2 antigen was found with decreased frequency in patients whereas no DR3/DR4 heterozygotes were observed. Our data support the hypothesis that a group of Type 2 diabetic patients with secondary failure to oral hypoglycaemic agents presented autoimmunity towards pancreatic Beta cells.

Analysis of Variance↗
PubMed1992

High-protein diet: effect on insulin secretion patterns from streptozotocin-diabetic rats and mice.

In the present study we have investigated the effect of a high-protein feeding on glucose induced-insulin secretion patterns from high dose streptozotocin (SZ) injected rats and mice, and from mice given multiple low doses of SZ. For this purpose male rats and mice were fed either a high-protein, carbohydrate-free diet, or control diets, before and after i.p. injections of SZ, or citrate buffer only. Our results show that when SZ was given as a single diabetogenic dose, rats and mice kept on the high-protein diet presented lower serum glucose levels, normal basal insulin values, and higher first and second phases of stimulated insulin release, when compared with diabetic animals on control diets. Furthermore, when rats prolonged their high-protein feeding from 4 to 11 days after SZ injection, there was an additional increment in insulin secretory capacity with a further diminution in serum glucose levels. We also show that high-protein feeding in mice given multiple low doses of SZ (a model of autoimmune diabetes), produced a diminution in serum glucose values, and an improvement in both phases of stimulated insulin release. Thus, in the two models of experimental diabetes used here, high-protein feeding exerts beneficial effects in beta cell responsiveness to glucose.

Animals↗
PubMed1992

[The effect of a protein-free diet on insulin and somatostatin secretion in rats].

We have used a model of experimental protein-energy malnutrition induced in weaned rats by administration of a protein free diet during 2 weeks. Some malnourished rats were then refed with a control diet for 4, 9 or 30 days. Control rats were fed for the same periods with the balanced control diet. Malnourished rats showed a loss in body weight of approximately 25%. After 30 days of refeeding, the animals gained weight reaching values higher than that of control rats. Insulin secreted by perifused pancreatic slices from malnourished rats, was impaired in first and second glucose-induced secretory phases. Basal secretion was also diminished in incubation of pancreatic slices. When malnourished rats were refed for 4 days, basal insulin secretion reached control values. Stimulated insulin secretion was normalized at 9 and 30 days of refeeding. Our result on somatostatin (SRIF) secretion in malnourished rats showed basal hypersecretion and diminished first and second glucose-induced secretory phases. During refeeding basal SRIF secretion was normalized from day 4. On the contrary stimulated secretion was significantly increased at 4 and 9 days of refeeding, and on day 30 values did not differ from controls. In protein energy malnutrition, the disturbed hormonal state can represent adaptative mechanisms to the protein depletion and hormonal changes have also an essential role in refeeding.

Animals↗
PubMed1991

[Insulin/glucagon relationship in spontaneous diabetic remission].

We define diabetic remission as the disappearance of clinical symptoms with normalization of blood glucose for a period over 15 days after withdrawal of insulin therapy. We studied 21 insulin-dependent diabetic children in remission (10 boys and 11 girls) and 29 normal children matched in age and sex as controls. Two tests were performed, intravenous glucose (IVGT) and glucose post-tolbutamide (PTGT). Two remission groups were studied with IVGT. Glucose, insulin, somatotropin and glucagon were determined in one and glucose and C-peptide in the other. Insulin secretion after IVGT was very low in the remission group, not surpassing basal value when stimulated. Only two girls showed normal or high insulin values during the study, and one of them showed the common hypoinsulinism of the remission group in a second study. The kinetics of glucagon and somatotropin secretion in the remission group were normal with low values of glucagon. When the integrated area (0-120 min) of hormone secretion (insulin, somatotropin and glucagon) was determined, the remission group had lower insulin and glucagon values (p less than 0.05) and identical growth hormone as the normal group. The insulin/glucagon ratio in normals and in remission were similar. During IVGT the remission group studied for C-peptide showed lower C-peptide values than normal group, resembling insulin behavior. In both groups, the glucose disappearance rate ("K" value) was higher in normals than in remissions (p less than 0.001). During the PTGT the normal group showed a peak of insulin secretion after tolbutamide and glucose stimulation. In the remission group, glucose was higher and insulin secretion lower than in the normal group, without a peak of insulin, and growth hormone and glucagon secretion were also lower.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1989

Glucagon secretion and alpha-cell sensitivity to somatostatin in genetically diabetic mice C57BL/KsJ-mdb.

In previous studies in C57BL/KsJ mdb/mdb mice, we observed alterations in glucose-induced insulin secretion in vitro, and a defective inhibitory effect of somatostatin on insulin secretion. In this work we studied glucagon secretion patterns under arginine-glucose stimulation, in perifused pancreatic slices from genetically diabetic mice aged 20 to 90 days. We also explored whether alpha-cells present a diminished sensitivity to somatostatin. Results showed that: a) in mdb/mdb mice aged 20 to 90 days, glucagon secretion patterns exhibited basal hypersecretion and a diminished first peak; b) somatostatin inhibited stimulated-glucagon secretion below baseline values in mdb/mdb mice aged 20 to 30 days. In later stages (40 to 90 days), somatostatin exerted a lower inhibitory effect since glucagon levels remain above basal values. This could indicate a progressive impairment in alpha-cell sensitivity to somatostatin, as it was previously observed in beta-cells.

Age Factors↗
PubMed1988

First phase of insulin secretion stimulated by glucose plus theophylline and inhibitory effect of somatostatin in genetically diabetic mice (C57BL/KsJ-mdb).

In a previous study in C57BL/KsJ mdb/mdb mice aged 4 to 12 days we observed a diminished first phase of glucose-induced insulin secretion in vitro, and alterations in the inhibitory effect of somatostatin on insulin secretion. This study explores, using perifused pancreatic slices, whether the reduced B-cell responsiveness to somatostatin in mdb/mdb mice can be overcome upon induction of a biphasic insulin release by using theophylline. Under these conditions our results show: (1) in mdb/mdb mice aged 4 to 6 days, the restoration of the first peak of insulin secretion overcomes the reduced B-cell sensitivity to somatostatin; and (2) in mdb/mdb mice aged 7 to 12 days, the addition of theophylline only causes a partial restoration of B-cell responsiveness to somatostatin, suggesting that other mechanisms could be involved in the progressive impairement of B-cell sensitivity to somatostatin inhibitory effect.

Aging↗
PubMed1988

Effect of superior cervical ganglionectomy on insulin release by murine pancreas slices.

The effect of superior cervical ganglionectomy (SCGx) on basal and glucose-stimulated insulin release in vitro was examined in pancreas slices of BALB/c mice subjected to surgery 14-96 h earlier. Fourteen or 20 h after SCGx a significant increase of insulin response to 11 mM glucose was detectable, while 96 h after SCGx a depression in response was found. Perifused pancreas slices obtained from mice subjected to SCGx 7 days earlier showed a decreased in vitro insulin response to glucose during both phases of insulin secretion. In sham-operated mice, injection of the beta-adrenoceptor blocker propranolol or of the cholinergic muscarinic antagonist atropine decreased basal and glucose-stimulated insulin release, while the alpha-adrenoceptor blocker phenoxybenzamine did not affect it significantly. In mice subjected to SCGx 14 h earlier, propranolol treatment decreased basal insulin release and impaired the release elicited by glucose to values similar to those found in controls, phenoxybenzamine injection increased the basal and amplified the enhanced glucose-stimulated insulin release, and atropine injection, although unable to affect basal insulin release, impaired partially the amplification of response detectable after surgery. Our results support the existence of significant effects of SCG neurons on insulin release in mice.

Animals↗