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Biomedical subjects

F Legros

Publications and source records attributed to F Legros.

At least 55 records · Page 3Linked to original sources
PubMed1981

alpha-Melanocyte-stimulating hormone binding and biological activity in a human melanoma cell line.

Synthetic alpha-melanocyte-stimulating hormone (alpha-MSH) was found to bind to the plasma membrane of the HM6A human melanoma cell line, using an immunocytochemical method. When treated with 10(-7) to 10(-9) M alpha-MSH, melanoma cells exhibited an increase of intracellular cyclic adenosine 3':5'-monophosphate, followed by stimulation of tyrosinase activity. Significant inhibition of DNA synthesis measured by [3H]thymidine uptake and inhibition of cell growth was found. A retrovirus expression was detected in the supernatant of HM6A cells as assayed by the KC cell syncytium-forming test. In he presence of 10(-7) M alpha-MSH, the number of syncytium-forming units was increased 15-fold. These results demonstrate that alpha-MSH modulates human melanoma differentiation and virus expression in vitro.

Cell Differentiation↗
PubMed1976

Insulin receptor sites as membrane markers during embryonic development. I. Data obtained with unfertilized and fertilized sea urchin eggs.

Binding of insulin to sea urchin egg plasma membrane has been studied by biochemical and immunocytochemical methods. Unfertilized and fertilized eggs as well as embryos during the first cell division have been used. 1. Competition experiments between 125I-insulin (1 nM) and an excess of native insulin (30 muM) indicate a specific hormone fixation to membrane crude extracts from unfertilized and fertilized eggs. The magnitude of "specific binding" is comparable to values recorded for mammalian cells. 2. Inhibition of insulin fixation by concanavalin A (100 mug/ml) suggests the glycoprotein composition of plasma membrane receptors. 3. An 30-min incubation of unfertilized and fertilized eggs in the presence of insulin leads to a significant increase in cyclic AMP content. 4. An immunocytochemical method demonstrates that insulin is selectively and specifically bound to the plasma membrane of eggs incubated in the presence of insulin before fixation. It can be concluded that insulin receptor sites are components of sea urchin eggs plasma membrane. Insulin binding which leads to cyclic AMP accumulation is not deeply modified by fertilization and does not include visible morphological changes in the eggs.

Animals↗
PubMed1975

[Intracellular processes leading to the induction of insulin membrane receptors. Study on Acetabularia mediterranea].

Algal cells have been incubated for 7 to 10 days in darkness in sea water containing either actinomycin D or cycloheximide (10 mug/ml) or fructose glucose (5.5 mM). Measurements of insulin fixation to whole cells, plasma membranes or cytosol fractions after that treatment indicate that dark consumption of chloroplastic fructosans stored in photosynthetic conditions would lead to a "signal" inducing translation and transcription of nuclear DNA genetic message resulting in an increase of the number of insulin cellular receptor sites.

Acetabularia↗