Restoration of glucagon responsiveness in spontaneously transformed rat hepatocytes (RL-PR-C) by fusion with normal progenitor cells and rat liver plasma membranes.

Reilly, Thomas M.; Blecher, Melvin

doi:10.1073/pnas.78.1.182

Cited by 8 publications

References 29 publications

(23 reference statements)

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Alterations in hormone-sensitive adenylate cyclase of cloned rat osteosarcoma cells during long-term culture

Gutiérrez

Mundy

Katz

1986

Journal of Bone and Mineral Research

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The hormone-sensitive adenylate cyclase system of a cloned bone cell line (UMR-106) derived from a rat osteosarcoma was compared in preparations from cells of early passages (less than 50) and cells maintained in continuous culture for over two years (late passages). Late passage cells showed greater calcitonin (CT)-stimulated adenylate cyclase activity than did early passages, whereas stimulation by PTH and the beta-adrenergic agonist isoproterenol decreased in late passages. Hormone concentrations giving half-maximal stimulation were the same in early and late passages. Stimulation by agents (GTP and fluoride) which act at the stimulatory guanine nucleotide regulatory component (Ns) of adenylate cyclase was equivalent in early and late passages. Forskolin stimulation, which assessed catalytic component (and possibly Ns) activity, was reduced in late passages. These results are consistent with acquisition by cultured UMR-106 cells of CT receptors linked to adenylate cyclase and loss of PTH and beta-adrenergic receptors. Alteration of catalytic component (and/or Ns) function may also occur after long-term culture. Since late passage cells appear dedifferentiated by chromosomal analysis and since cAMP may regulate differentiation, altered hormone-sensitive adenylate cyclase may be a marker for and a potential modulator of differentiation occurring in UMR-106 cells over long periods.

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Alterations in hormone-sensitive adenylate cyclase of cloned rat osteosarcoma cells during long-term culture

Gutiérrez

Mundy

Katz

1986

Journal of Bone and Mineral Research

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Expression of glucagon sensitivity by transformed MDCK cells normally unresponsive to glucagon: Early commitment to differentiation

Beckner

Lin

1985

Journal Cellular Physiology

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A cloned line of canine kidney cells (MDCK) transformed with Harvey murine sarcoma virus, in contrast to the parental, untransformed line, expressed glucagon sensitivity only under controlled culture conditions. The glucagon sensitivity of transformed MDCK cells appeared after 10 days of culture if plated at less than 100,000 cells/dish or after 3 days if cells were plated at greater than 300,000 cells/dish. As there was no effect of conditioned medium from glucagon-sensitive cells on insensitive cells, media components seemed not to be involved in this phenomenon. Glucagon sensitivity appeared more readily in defined as opposed to serum-containing medium. In fact, as little as 2% fetal bovine serum inhibited the expression of glucagon sensitivity when included in defined medium over the course of the experiment. Furthermore, when transformed MDCK cells were exposed to serum for only the first 24 hr of culture, glucagon sensitivity on day 11 was identical to that of cells exposed to serum throughout the entire experiment. In contrast, exposure to serum later in culture (days 4-8) had no inhibitory effect on the expression of glucagon sensitivity on day 11. The data suggest that differentiation, or glucagon sensitivity, occurs when transformed, glucagon-insensitive cells achieve a critical high density and that differentiation is sensitive to inhibition by serum only during the first 24 hr of culture.

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Role of the β-Adrenergic Receptor in the Regulation of Adenylate Cyclase

1984

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Restoration of glucagon responsiveness in spontaneously transformed rat hepatocytes (RL-PR-C) by fusion with normal progenitor cells and rat liver plasma membranes.

Abstract: Spontaneously transformed RL-PR-C rat hepatocytes, unlike their normal differentiated progenitor

Cited by 8 publications

References 29 publications

Alterations in hormone-sensitive adenylate cyclase of cloned rat osteosarcoma cells during long-term culture

Alterations in hormone-sensitive adenylate cyclase of cloned rat osteosarcoma cells during long-term culture

Expression of glucagon sensitivity by transformed MDCK cells normally unresponsive to glucagon: Early commitment to differentiation

Role of the β-Adrenergic Receptor in the Regulation of Adenylate Cyclase

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