Cell Fractionation by Centrifugation Methods.- - Introduction.- - Homogenization.- - Fractionation methods.- - Analysis of the fractions and interpretation of the results.- - Conclusion.- - References.- Binding of Ligands to Receptors: Theory.- - Introduction.- - Experimental approach to the hormone-receptor interaction.- - Molecular models of receptors.- - Graphical representations of saturation experiments.- - Methodologic errors and graphical representations.- - Conclusion.- - References.- On the Modes of Regulation of Intracellular Cyclic AMP: Desensitization of Adenylyl Cyclases to Hormon.