Increased Permeability of the Frog Bladder to Water in Response to Dehydration and Neurohypophysial Extracts

Dehydration, neurohypophysial extracts and synthetic oxytocin all increase the rate of reabsorption of urine from the bladder of the frog. Increased permeability of the frog bladder to water, facilitating the osmotic flow of water, appears to be the basis for this response. Increased permeability of the skin and the renal tubule occurs under similar circumstances. The hypothesis is advanced that a common mechanism is involved, possibly the dilatation of pores, in response to neurohypophysial hormones in amphibian skin, bladder and nephron and in the mammalian nephron.