PubMed Health⌕ Search

Biomedical subjects

G Ribes

Publications and source records attributed to G Ribes.

116 records · Page 7Linked to original sources
PubMedDate not supplied

Long-term antidiabetic activity of vanadyl after treatment withdrawal: restoration of insulin secretion?

In its vanadate (V5+) or vanadyl (V4+) forms, vanadium has been demonstrated to possess antidiabetic activity. Oral treatment of streptozotocin (STZ)-diabetic animals with either form is associated with correction of hyperglycemia, and prevention of diabetes-induced complications, although weight gain is unaffected. Vanadium treatment of non-diabetic animals lowers plasma insulin levels by reducing insulin demand, as these animals remain normoglycemic. These results suggest that vanadium has in vivo insulin-mimetic or insulin-enhancing effects, in agreement with several in vitro observations. Chronic treatment with vanadium has also been shown to result in sustained antidiabetic effects in STZ-diabetic animals long after treatment has ceased. Thus, at 13 weeks after withdrawal from treatment, corrected animals had normalized glucose and weight gain, and improved basal insulin levels. In addition, near-normal glucose tolerance was found despite an insignificant insulin response. Since vanadium accumulates in several tissue sites (e.g. bone, kidney) when pharmacological doses are administered, it is possible that stored vanadium may be important in maintaining near-normal glucose tolerance at least in the short-term following withdrawal from treatment. Recently, following withdrawal of vanadyl treatment up to 30 weeks, diabetic animals which had remained normoglycemic and had normalized glucose tolerance showed improvements in plasma insulin levels both in the basal state and in response to oral glucose, as compared to those which had reverted to hyperglycemia. The observed significant improvements in insulin capacity over the long-term ( > 3 months) suggests that a restored and/or preserved insulin secretion may be essential for maintained reversal of the diabetic state over a prolonged period after treatment is withdrawn.

Animals↗
PubMedDate not supplied

Long-term correction of STZ-diabetic rats after short-term i.p. VOSO4 treatment: persistence of insulin secreting capacities assessed by isolated pancreas studies.

We have previously shown that 3 week oral VOSO4 treatment of streptozotocin (STZ, 60 mg/kg)-induced diabetic rats was able to correct diabetes for 13 weeks after treatment withdrawal. In the present study, we investigated whether a short-term (8 days) i.p. VOSO4 treatment was similarly able to reverse the diabetic state. Insulin secretory capacities were assessed at distance of treatment using the isolated pancreas preparation. Seven treatment-groups were performed: high dose VOSO4-treated diabetics (HVD, 1.3 mM/kg/8 days), food-restricted diabetics (FRD, food adjusted to HVD levels), low dose VOSO4-treated diabetes (LVD, 0.06 mM/kg/day), insulin-treated diabetics (ID, dose adjusted to normalize glycaemia) and VOSO4 (0.06 mM/kg/day) + insulin (dose adjusted to normalize glycaemia in the presence of vanadium)-treated diabetics (IVD), in addition to the corresponding untreated non-diabetic controls (C) and diabetics (D). Our results indicate that long-term correction of diabetes (a) can be obtained after an 8 day treatment using i.p. VOSO4 in diabetic animals retaining some degree of pancreatic function, (b) is not obtained with insulin treatment or food restriction although the association of VOSO4 and insulin was found beneficial, (c) can be prolonged in some individuals for at least 4 months, i.e. in conditions such that tissue vanadium concentrations had returned to values close to pre-treatment levels, (d) is associated with improved and in some cases normalized insulin secretion from isolated pancreas. The protective or corrective role of VOSO4 on diabetes-related pancreatic alterations, as well as the potential of the VOSO4-insulin association should be further studied in view of the possible use of vanadium derivatives in the treatment of diabetes.

Animals↗
PubMedDate not supplied

Age-dependent changes in insulin-like immunoreactivity in rat submandibular salivary glands.

In recent years, a growing interest had arisen in hormonal factors in salivary glands. We have investigated the changes in the content of an insulin-like immunoreactive (ILI) compound in the submandibular salivary glands of Sprague Dawley rats during physiological aging, in the range 15 days-27 months. The amount of ILI in the submandibular glands of young adult rats was found to be doubled in the post-natal period until the age of puberty and was maintained in senescence. No significant correlation was found between age-dependent variations in ILI levels of submandibular salivary glands and circulating insulin concentrations, further supporting previous indications that ILI is being synthesized in situ. It is possible that ILI could exert paracrine effects within the glands, as regards the development of other glandular structures during the first months of life, as well as the preservation of glandular function in senescent animals as well.

Age Factors↗
PubMedDate not supplied

[Kinetic aspects of the glipizide-induced hypoglycemia in the dog (author's transl)].

The study of the kinetics of hypoglycemia induced by glipizide (second generation hypoglycemic sulfonamide) was carried out on the normal conscious dog. 1. In a first series of experiments glipizide was given intravenously at the dose of 0.1 mg .kg-1. The hypoglycemic effect of the drug occurred rapidly and reached a maximum at the 30th minute. This maximum effect did not much vary from one animal to another. The hypoglycemic action persisted at least 7 hours after the injection, and at the 24th hour blood glucose level returned practically to the initial values. 2. The kinetics of hypoglycemia after per os administration were studied when glipizide was given either in solid form preparation or in solution form. Glipizide given per os in powder form at the dose of 0.1 mg . kg-1 induced a kinetics of hypoglycemia which varied from one animal to another. The hypoglycemic effect which appeared within 1 to 4 hours after administration, reached its maximum within 2 to 6 hours; it ranged from -6 p. 100 to -52 p. 100. A tenfold higher dose (1 mg . kg-1) produced a hypoglycemia which occurred more rapidly, with less dispersion in the intensity of the response. When glipizide was given at the dose of 0.1 mg . kg-1 in solution form, it can be noted that in all cases hypoglycemia occurred earlier than after administration in powder form at the same dose, while the dispersion in the maximum effect is still considerable. These results lay stress once again on the importance of the form of administration on the kinetics of hypoglycemia and on its intensity.

Administration, Oral↗