ISSN:
1615-6102
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Summary Three methods have been used to study fixation of insulin to the unicellular algaAcetabularia mediterranea grown in darkness. 1. Significant cell radioactivity after dipping in125I-insulin dissolved in sea water, saturation kinetics of labelling, competition between radioactive and native insulins for cell fixation, acceleration of radioactive insulin release in the presence of native hormone, decrease of radioactivity attached to the cells in the presence of concanavalin A or after treatment with trypsin, effect of various concentrations of phospholipase C agree with data obtained on animal cells indicating a specific binding of insulin to receptor sites. 2. Homogenization of algae prelabelled with radioactive hormone has indicated that insulin preferentially binds to plasma membrane receptor sites. Some insulin molecules penetrate into the cell. 3. Immunocytochemical methods have confirmed that insulin binds to plasma membrane receptors and that some hormone molecules are located at the level of intracellular membranes and organelles.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF01275626
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