Activation of actin-containing microfilaments by vasopressin in the amphibian urinary bladder epithelium: a fluorescent study using NBD-phallacidin.

The effect of an antidiuretic hormone (ADH, vasopressin) on the microfilament system of the toad urinary bladder lumenal epithelium was investigated using NBD-phallacidin (NBD-ph). The latter material is a specific fluorescent label for F actin. In the presence of an osmotic gradient, both ADH and cyclic adenosine monophosphate (cAMP) appear to induce the polymerization of monomeric actin into F actin-containing microfilaments. The latter may then be involved in the morphological changes, including the formation of lateral intercellular lakes, associated with the typical hydroosmotic response.