Metabolic and Ultrastructural Changes Induced in Adipose Tissue by Insulin

Barrnett, Russell J.; Ball, Eric G.

doi:10.1083/jcb.8.1.83

Cited by 162 publications

(22 citation statements)

References 21 publications

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“…However, small specialized invaginations of the plasma membrane were more frequently observed in retinoltreated fibroblasts than in the controls, These small invaginations, and those seen in studies of erythrocytes , are reminiscent of the observations of Paul & Pearson (1960), and of Barrnett & Ball (1960), on the ultrastructural changes induced by insulin. However, small specialized invaginations of the plasma membrane were more frequently observed in retinoltreated fibroblasts than in the controls, These small invaginations, and those seen in studies of erythrocytes , are reminiscent of the observations of Paul & Pearson (1960), and of Barrnett & Ball (1960), on the ultrastructural changes induced by insulin.…”

Section: (4) Mammalian Fibroblastsmentioning

confidence: 53%

Vitamin A, Carotenoids and Cell Function

1965

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Summary I. Both deficiency and excess of vitamin A produce many diverse pathological changes. Lipoprotein membranes have recently been found to be concerned in a number of the actions of excess of the vitamin. This article is devoted principally to a discussion of the interactions and possible functions of vitamin A within membranes, both in hypervitaminosis and under physiological conditions. 2. Excess of vitamin A. (a) As a result of its amphipathic molecular structure, retinol is highly surface active. (b) The initial action of excess of retinol on erythrocytes is an expansion of the cell membrane; this is followed by haemolysis unless the cells are kept cold, or inhibitors, such as vitamin E, are present. (c) Addition of retinol to fibroblasts growing in vitro causes degranulation and swelling of the endoplasmic reticulum, swelling of Golgi vacuoles and mitochondria, and the formation of cytolysomes. (d) Isolated mitochondria from certain tissues also swell in the presence of retinol. This swelling is apparently not dependent on respiration, but is inhibited by vitamin E. (e) Lysosomal enzymes are released by excess of retinol, both in vivo and in vitro. A number of the effects of excess vitamin A on connective tissues may be ascribed to this action; these effects are inhibited by hydrocortisone, which stabilizes lysosomes, but are not significantly inhibited by vitamin E. (f) Closely related, but physiologically inactive, derivatives of retinol are relatively inactive towards membranes; membranes might therefore also be concerned in the physiological functions of retinol. (g) Vitamin A has recently been shown to have marked effects on the membranes of certain bacteria and viruses. 3. Deficiency of vitamin A. (a) The diminished synthesis of mucopolysaccharide observed in deficiency may result from an interference with the synthesis of ‘active sulphate’ but, in view of conflicting observations, this cannot be considered as proven. (b) Suggestions have been made that lipoprotein membranes may be concerned in the actions of vitamin A on both mucopolysaccharide and steroid biosynthesis. (c) The action of the vitamin in biological oxidations is far from clear. Recently it has been found that deficiency increases, and excess of vitamin A decreases, the oxidation of succinate by homogenates of rat liver. (d) Organ culture experiments indicate that vitamin A acts directly on mouse prostate glands to prevent the squamous changes that are characteristic of deficiency. 4. A conjugated chain of alternating single and double bonds is a chemical feature common to vitamin A and the carotenoids. (a) Such a chain is characterized by a high electron mobility; this has been studied both theoretically and experimentally in relation to electron transfer in photosynthesis, to ion transport, and to super‐conduction and semi‐conduction in biological systems. (b) The role of vitamin A in vision may be an evolutionary development of the function of the carotenoids in photosynthesis. In the eye, retinal is intimately conce...

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Section: (4) Mammalian Fibroblastsmentioning

confidence: 53%

Vitamin A, Carotenoids and Cell Function

1965

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“…In this connection, the abnormal T-system proliferation in both cultured and atrophied muscle might be somehow associated with the absence of innervation. It is possible that proteins or other substances in our culture medium stimulate multiple caveolation in the muscle cells much as they have been shown to stimulate pinocytosis in amebae (see Holter, 1959 and and in some mammalian cells (Barrnett and Ball, 1960). The overproduction of the T-system tubules in denervated muscle fibers (and in rather later stages after denervation, Pellegrino and Franzini, 1963) might be explained by assuming that some mate-FIGuRE 13 Ferritin experiment.…”

Section: Discussionmentioning

confidence: 99%

Formation of Elaborate Networks of T-System Tubules in Cultured Skeletal Muscle With Special Reference to the T-System Formation

Ishikawa

1968

The Journal of Cell Biology

238

109

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Muscle cells, cultured for 1-28 days from I 1-day chick embryo breast muscles, often show elaborate, three-dimensional networks of a membranous system. The network consists of tubular units which are quite regularly arranged. The tubular units composing the network are accessible to ferritin particles suspended in the culture medium; this suggests continuity with the extracellular fluid. These networks can be regarded as a special morphological elaboration of the T-system tubules. Such network formations can be seen much more often in well-developed myotubes. The networks usually exhibit a hexagonal pattern, which is formed of tubular units of a constant diameter. However, some early myotubes contain tetragonal networks, which are composed of spherical pockets with channels of lesser diameter connecting the pockets. Networks are also observed which probably represent a transitional form between these two patterns. Myotubes show many inpocketings of the sarcolemma similar to what are commonly referred to as caveolae or micropinocytotic vesicles. The similarity in configuration and dimension of the tubular units of the network to the caveolae leads to the plausible suggestion that repeated caveola-formation from the sarcolemma or T-system tubule may result in formation of these networks. In this connection, a possible mechanism of the T-system tubule formation is discussed.

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“…Adipocytes have a signet-ring appearance with a large central amorphous fat deposit, an eccentric nucleus and a thin layer of cytoplasm containing mitochondria, the endoplasmic reticulum and the Golgi apparatus (2,10,11,21,22,30,31,32,33). The adipocyte membrane shows numerous microvesicular invaginations and is covered by a basal membrane (Fig.…”

Section: Resultsmentioning

confidence: 99%

“…The fine structure of adipocytes in young rats has been examined by conventional thin-section electron microscopy by many investigators (2,3,10,11,21,23,27,30,31,32,33), but there are few reports on the morphology of adipocytes of obese rats. This may be because of the technical difficulty of examining these cells by electron microscopy owing to their very high lipid content.…”

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confidence: 99%