Experimental Diabetes Impairs Endothelial IKCa Channel Function in Uteroplacental Arteries from Pregnant Rats

This present study has demonstrated that during normal pregnancy in the rat the number of β-cells is increased (hyperplasia) and the volume of the individual β-cells is increased (hypertrophy). During experimental diabetes, however, the endocrine pancreas has an impaired capacity to compensate during pregnancy. In the experimental diabetic pregnant rat the β-cells cannot replicate due to the unfavourable metabolic environment. This could reflect the complications caused by diabetes during human pregnancy.

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Methyl-Beta-Cyclodextrin Restores KIR Channel Function in Brain Endothelium of Female Alzheimer’s Disease Mice

Journal of Alzheimer s Disease Reports ◽

10.3233/adr-210016 ◽

2021 ◽

Vol 5 (1) ◽

pp. 693-703

Author(s):

Md A. Hakim ◽

Erik J. Behringer

Keyword(s):

Alzheimer’S Disease ◽

Alzheimer's Disease ◽

The United States ◽

Extracellular Potassium ◽

Membrane Cholesterol ◽

Brain Endothelium ◽

Channel Function ◽

Kir Channel ◽

Before And After ◽

Ikca Channel

Background: As the sixth-leading cause of death in the United States, Alzheimer’s disease (AD) entails deteriorating endothelial control of blood flow throughout the brain. In particular, reduced inward-rectifying K+ (KIR) channel function in animal models of aging and AD compromises endothelial function and optimal perfusion of brain parenchyma. Deficient endothelial KIR channels may result from aberrant interaction with plasma membrane cholesterol as a primary regulator of membrane fluidity and ion channels. Objective: We tested the hypothesis that mild methyl-β-cyclodextrin (MβCD) treatment to reduce membrane cholesterol may restore endothelial KIR channel function in brain endothelium of old AD mice. Methods: Membrane potential was continuously measured in isolated endothelial tubes from posterior cerebral arteries of young (1 to 3 months) and old (16 to 19 months) female 3xTg-AD mice before and after mild treatment with the cholesterol-removing agent MβCD (1 mmol/L). Elevated extracellular potassium ([K+]E; 15 mmol/L) and NS309 (1μmol/L) activated KIR and Ca2+-activated K+ (SKCa/IKCa) channels respectively before and after MβCD treatment. Results: SKCa/IKCa channel function for producing hyperpolarization remained stable regardless of age group and MβCD treatment (ΔVm: ∼–33 mV). However, as deficient during AD, KIR channel function was restored (ΔVm: –9±1 mV) versus pre-MβCD conditions (–5±1 mV); a progressive effect that reached –14±1 mV hyperpolarization at 60 min following MβCD washout. Conclusion: In female animals, MβCD treatment of brain endothelium selectively restores KIR versus SKCa/IKCa channel function during AD. Thus, the endothelial cholesterol-KIR channel interface is a novel target for ameliorating perfusion of the AD brain.

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Effects of experimental diabetes on the vitamin D metabolism of pregnant rats and their fetuses

Calcified Tissue International ◽

10.1007/bf02556345 ◽

1988 ◽

Vol 42 (2) ◽

pp. 127-135 ◽

Cited By ~ 10

Author(s):

J. Demignon ◽

C. Rebut-Bonneton

Keyword(s):

Vitamin D ◽

Experimental Diabetes ◽

Vitamin D Metabolism ◽

Pregnant Rats

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gamma-Linoleic acid and ascorbic acid ameliorate the effects of experimental diabetes on electrolyte and bone homeostasis in pregnant rats

Journal of Endocrinology ◽

10.1677/joe.0.1730273 ◽

2002 ◽

Vol 173 (2) ◽

pp. 273-284 ◽

Cited By ~ 1

Author(s):

R Braddock ◽

CM Siman ◽

K Hamilton ◽

H Devlin ◽

H Garland ◽

...

Keyword(s):

Linoleic Acid ◽

Experimental Diabetes ◽

Urine Volume ◽

Diabetic Rats ◽

Control Group ◽

Bone Homeostasis ◽

Pregnant Rats ◽

Significant Difference ◽

Urine Production ◽

Electrolyte Loss

Experimental diabetes in rats is associated with excessive electrolyte loss in the urine, which is further accentuated by pregnancy, particularly of Ca. Supplementation with essential fatty acids and antioxidants has proven beneficial in treating several types of complications, including nephropathy. The present study investigated the effect of gamma-linoleic acid (GLA; 500 mg/kg per day; group DG) and ascorbate (290 mg/kg per day; group DA), alone and in combination (group DGA), as well as ascorbyl-GLA (790 mg/kg per day; group DASG), on urinary electrolyte output and skeletal composition in pregnant streptozotocin-diabetic rats. Urine was collected in metabolism cages before and throughout pregnancy. Diabetic rats (DP) increased their urine volume as compared with control (CP) throughout the experiment, reaching an output of more than 13 times that of the control group by the end of pregnancy (CP 24+/-4, DP 316+/-21, DG 223+/-21, DA 221+/-14, DASG 163+/-17, DGA 220+/-19 ml urine/24 h). Concomitant with increased urine volume was a reduction of urinary Na (CP 47+/-14, DP 22+/-5 mmol/l), K (CP 210+/-34, DP 31+/-1 mmol/l) and Mg (CP 14+/-1, DP 3.8+/-0.2 mmol/l) concentration, but not of Ca concentration (CP 5.4+/-1.5, DP 6.3+/-0.6 mmol/l), and hence total Ca loss was relatively most severe. All the treatments reduced urine volume with no effects on electrolyte concentration as compared with DP, with no significant difference between the treatments. A reduced bone size and bone Ca content was partially ameliorated by the diet supplementation. We have concluded that GLA and ascorbate, alone or in combination, prevent urinary electrolyte loss in pregnant rats and do so by reducing urine production.

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Modification of Pineal Ultrastructure by Exogenous Hormones

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100060866 ◽

1967 ◽

Vol 25 ◽

pp. 170-171

Author(s):

R. A. Turner ◽

A. E. Rodin ◽

D. K. Roberts

Keyword(s):

Electron Microscopy ◽

Endoplasmic Reticulum ◽

Rough Endoplasmic Reticulum ◽

Estradiol Benzoate ◽

Female Rats ◽

List Type ◽

Type Number ◽

Pregnant Rats ◽

Gonadal Atrophy ◽

Pineal Ultrastructure

There have been many reports which establish a relationship between the pineal and sexual structures, including gonadal hypertrophy after pinealectomy, and gonadal atrophy after injection of pineal homogenates or of melatonin. In order to further delineate this relationship the pineals from 5 groups of female rats were studied by electron microscopy:ControlsPregnant ratsAfter 4 weekly injections of 0.1 mg. estradiol benzoate.After 8 daily injections of 150 mcgm. melatonin (pineal hormone).After 8 daily injections of 3 mg. serotonin (melatonin precursor).No ultrastructural differences were evident between the control, and the pregnancy and melatonin groups. However, the estradiol injected animals exhibited a marked increase in the amount and size of rough endoplasmic reticulum within the pineal cells.

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