Effects of prolactin on ventricular myocyte shortening and calcium transport in the streptozotocin-induced diabetic rat

The effects of insulin and thyroid hormone treatments on cardiac sarcoplasmic reticular function were investigated in chronic streptozotocin-induced diabetes in rats. ATP-dependent Ca2+ transport and Ca2+-stimulated ATPase activities were depressed significantly in microsomal samples from diabetic rats in comparison with control (P less than 0.05). This defect was seen at various times of incubation (1-20 min) and different concentrations of free Ca2+ (10(-7) to 10(-5) M Ca2+) and was accompanied by changes in the protein composition and phospholipid contents of the microsomal fraction. The defect in calcium transport in microsomal vesicles was not evident until 28 days after streptozotocin (65 mg/kg iv) injection, whereas increases in plasma glucose levels due to insulin-deficiency occurred within 3 days. All changes in function and composition of the sarcoplasmic reticulum were reversed by insulin administration to the diabetic rats. Although the plasma level of thyroid hormone was decreased in the diabetic rat, thyroid hormone treatment did not restore microsomal calcium transport in the diabetic animals. The results of this study provide some evidence that the depression in cardiac sarcoplasmic reticular calcium accumulation during diabetes is a consequence of insulin deficiency and associated chronic metabolic changes but the hypothyroid condition that accompanies experimental diabetes does not appear to play any role in this defect.

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The effects of heavy long-term exercise on ventricular myocyte shortening and intracellular Ca2+ in streptozotocin-induced diabetic rat

Journal of Diabetes and its Complications ◽

10.1016/j.jdiacomp.2009.03.001 ◽

2010 ◽

Vol 24 (4) ◽

pp. 278-285 ◽

Cited By ~ 10

Author(s):

Frank Christopher Howarth ◽

Fadwa A. Almugaddum ◽

Muhammud A. Qureshi ◽

Milos Ljubisavljevic

Keyword(s):

Diabetic Rat ◽

Ventricular Myocyte

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Contraction and intracellular calcium transport in epicardial and endocardial ventricular myocytes from streptozotocin-induced diabetic rat

Hamdan Medical Journal ◽

10.4103/hmj.hmj_32_18 ◽

2019 ◽

Vol 12 (3) ◽

pp. 111

Author(s):

FrankChristopher Howarth ◽

ManalM A. Smail ◽

MuhammadAnwar Qureshi ◽

Anatoliy Shmygol ◽

Jaipaul Singh ◽

...

Keyword(s):

Intracellular Calcium ◽

Calcium Transport ◽

Ventricular Myocytes ◽

Diabetic Rat

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Cardiac sarcoplasmic reticulum function in insulin- or carnitine-treated diabetic rats

AJP Heart and Circulatory Physiology ◽

10.1152/ajpheart.1983.245.6.h969 ◽

1983 ◽

Vol 245 (6) ◽

pp. H969-H976 ◽

Cited By ~ 18

Author(s):

G. D. Lopaschuk ◽

A. G. Tahiliani ◽

R. V. Vadlamudi ◽

S. Katz ◽

J. H. McNeill

Keyword(s):

Sarcoplasmic Reticulum ◽

Calcium Transport ◽

Heart Function ◽

Diabetic Rats ◽

Left Ventricular ◽

Diabetic Rat ◽

Cardiac Sarcoplasmic Reticulum ◽

Rat Hearts ◽

Developed Pressure ◽

Heart Apparatus

Cardiac sarcoplasmic reticulum (SR) function and SR levels of long-chain (LC) acylcarnitines were determined in streptozotocin-induced diabetic rats treated with insulin or D,L-carnitine. ATP-dependent calcium transport was significantly depressed in cardiac SR isolated from untreated diabetic rats compared with control rats. Diabetic rat cardiac SR levels of LC acylcarnitines were also significantly elevated. Various parameters of heart function (left ventricular developed pressure, +dP/dT, and -dP/dT), as determined on an isolated working heart apparatus, were found to be depressed in untreated diabetic rats. Cardiac SR isolated from diabetic rats treated throughout the study period with insulin or D,L-carnitine did not have elevated levels of LC acylcarnitines associated with SR membrane nor was SR calcium transport activity depressed. Heart function in the diabetic rats treated with insulin was similar to control rat hearts but heart function remained depressed in diabetic rats treated with D,L-carnitine. The data suggest that the LC acylcarnitines are involved in the observed impairment of cardiac SR function in diabetic rats. Other factors, however, must be contributing to the depression in heart function noted in these animals.

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Ca++-ATPase activity in the hepatopancreas cells of Oniscus asellus

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100124501 ◽

1992 ◽

Vol 50 (1) ◽

pp. 820-821

Author(s):

G.M. Vernon ◽

A. Surace ◽

R. Witkus

Keyword(s):

B Cells ◽

Epithelial Cell ◽

Atpase Activity ◽

Calcium Transport ◽

Carcinus Maenas ◽

Cell Types ◽

Molt Cycle ◽

Copper And Zinc

The hepatopancreas consists of a pair of bilobed tubules comprised of two epithelial cell types. S cells are absorptive and accumulate metals such as copper and zinc. Ca++ concentrations vary between the S and B cells and during the molt cycle. Roer and Dillaman implicated Ca++-ATPase in calcium transport during molting in Carcinus maenas. This study was undertaken to compare the localization of Ca++-ATPase activity in the S and B cells during intermolt.

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Immunogold localization of calmodulin in root caps of the maize Cultivar Merit

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100160923 ◽

1990 ◽

Vol 48 (3) ◽

pp. 674-675

Author(s):

P.T. Nguyen ◽

C. Uphoff ◽

C.L. Stinemetz

Keyword(s):

Calcium Binding ◽

Calcium Transport ◽

Primary Role ◽

Immunogold Localization ◽

Root Tips ◽

Electrical Currents ◽

Considerable Evidence ◽

Maize Cultivar ◽

Gravity Response ◽

Induced Changes

Considerable evidence suggest that the calcium-binding protein calmodulin (CaM) may mediate calcium action and/or transport important in the gravity response of plants. Calmodulin is present in both shoots and roots and is capable of regulating calcium transport in plant vesicles. In roots calmodulin is concentrated in the tip, the gravisensing region of the root; and is reported to be closely associated with amyloplasts, organelles suggested to play a primary role in gravi-perception. Inhibitors of CaM such as chlorpromazine, calmidazolium, and compound 48/80 interfere with the gravitropic response of both snoots and roots. The magnitude of the inhibition corresponded well with the extent to which the drug binds to endogenous CaM. Compound 48/80 and calmidazolium block gravi-induced changes in electrical currents across root tips, a phenomenon thought to be associated with the sensing of the gravity stimulus.In this study, we have investigated the subcellular distribution of CaM in graviresponsive and non-graviresponsive root caps of the maize cultivar Merit.

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Troglitazone prevents falty changes of the liver in obese diabetic rat

Gastroenterology ◽

10.1016/s0016-5085(01)81032-5 ◽

2001 ◽

Vol 120 (5) ◽

pp. A207-A208

Author(s):

D JIA ◽

T AKIYAMA ◽

K FUKUMITSU ◽

M YAMAMOTO ◽

S ABE ◽

...

Keyword(s):

Diabetic Rat

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