Autoradiographic Localization and Characterization of Angiotensin II Receptors: DISCUSSION(2)


Autoradiography showed a marked 125I-[Sar1-Ile5-Ile8]-Ang II binding in the intercotyledonary membrane and the placentome, whereas the binding to the allantoamnionic membrane appeared less intense. Data from Ang II receptor binding studies showed, however, that the amount of receptor related to the extracted cell membrane protein (Table 2) was lower in the placentome than in the allantoamnionic and intercotyledonary membrane. The allantoamnionic membrane is a tissue that contains relatively few scattered cells, whereas the intercotyledonary membrane and the pla-centome have a much higher cell density. flovent inhaler

In these tissues, much more cell membrane protein can thus be extracted per gram of tissue. Therefore, the amount of Ang II receptor per gram wet tissue was higher in the placentome than in the allantoamnionic membrane (Table 3). This corresponds with the Ang II receptor densities observed in the autoradiograms. Our findings underline the possibility that receptor densities obtained by visual subjective scoring or by computer-assisted conversion of the optical density of autoradiograms, as in reference, may not be comparable with those obtained by receptor binding studies, in which the amount of receptor is related to the cell membrane protein as in Table 2 in this paper.

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