Toad

About: Toad is a research topic. Over the lifetime, 1624 publications have been published within this topic receiving 28732 citations.

Renal function during osmotic stress in the aquatic toad Xenopus laevis.

Abstract: MCBEAN, RALPH L., AND LEON GOLDSTEIN. Renal function during osmotic stress in the aquatic toad Xenopus laevis. Am. J. Physiol. 2 19 (4) : 1115-1123. 1970.~Xenopus toads, which are normally aquatic and arnmonotelic, became ureotelic after maintenance in a hyperosmotic saline solution for 2-3 weeks. In addition, blood urea levels were elevated more than 15-fold, and this increase contributed significantly to achieving osmotic balance in the animals. Within a few hours after transfer of the toads to saline, urine flow fell to ${o of the rate in freshwater. By 7 days after transfer, flow had returned to about one-fourth of the freshwater level, where it remained. Changes in glomerular filtration rate paralleled those in urine flow. It was estimated that the reduction in urine flow was essential to the observed urea accumulation; however, an increase in net urea synthesis also appeared necessary. The suppression of urine flow in Xenopus after transfer to saline appeared to be related to an increase in plasma sodium concentration. Dehydration per se did not occur.

Hypophyseal Functions in the Toad Bufo Arenarum Hensel

Abstract: BY BERNARDO A. HOUSSAY Instituto de Biologia y Medicina Experimental, Buenos Aires T H HE study of the functions of the hypophysis of Bufo arenarum Hensel (and other batrachians) was started forty years ago in Argentina. This toad is perhaps the species in which the largest number of functions related to the hypophysis has been found and studied. The importance of this work lies in the general principle of endocrinology that hormonal actions have a fundamental similarity in all species. The hypophysis is necessary for the preservation of the life of the individual toad and also of the species. Its removal is followed by metabolic disturbances which are fatal in a few weeks, and by interference with the sexual functions, which prevents reproduction. Personal experience with over twenty thousand individuals of the species Bufo arentarum Hensel, has convinced the author of the many advantages it has for experimental purposes. It is easy to obtain in large numbers cheaply. It has great resistance to trauma. It offers facility of operative techniques; a great variety and severity of the symptoms of hypophyseal insufficiency; rapidity and intensity in its response to the implantation of one or the other of the lobes of the hypophysis; and the possibility of making experiments and obtaining p)roofs more easily and in larger numbers than with any other animal.. This toad is preferable to the frog Leptodactylus ocellatus (L.) Gir., which was studied in 1910 to 1916 and in 1924, and which is common in the Argentina, but is much less resistant. The symptoms of hypophysectomy or hypophyseal insufficiency observed in Bufo arenarum are very similar, except for slight differences, in Leptodactylus ocellatus (L.) Gir. (Houssay, 1910, 1916; Houssay and Ungar, 1924a, b, 1925a, b); Bufo marinus, Bufo paracnemis, Bufo d'Orbigny, Ceratophrys ornata, Hyla sp., and Atelopus telzneri. (In the first papers published by myself and my collaborators Bufo arenarum Hensel was mistakenly called Bufo marinus (L.) Schneid, according to the advice of the zoologists consulted; but in 1930 the error was corrected and since then the right name has been used.)