Mudpuppies Research Articles

Carbonic anhydrase and red blood cell anion exchange in the neotenic aquatic salamander, Necturus maculosus.

Carbonic anhydrase (CA) activity in blood and other tissues and red blood cell (rbc) anion exchange were measured in the mud puppy, Necturus maculosus, in order to gain insight into the strategy for CO2 transport used by these neotenic salamanders and to further explore evolutionary relationships between rbc CA activity and anion exchange in nonmammalian vertebrates. CA activity was detectable in all of the tissues examined, but CA activity in blood was much lower than that in most vertebrates. There was no indication, however, that additional CA had been incorporated into the membrane fraction of other tissues to compensate for this low blood CA activity. In further contrast to most other animals, low levels of CA activity were also detectable in mud puppy plasma. Preliminary characterization of the rbc CA indicated that the Type II, fast-turnover enzyme was indeed present, but that there are a very low number of active sites in mud puppy rbc's. Further experiments showed that the rbc's were highly permeable to anions and that the relative rate of anion flux could be inhibited by 4, 4-diisothiocyanostilbene-2,2-disulphonic acid. Thus, the process of CO2 transport in the blood of mud puppies probably involves components of the Jacobs-Stewart cycle, as in most other vertebrates.

Pituitary and prolactin influences on calcium regulation in the mud puppy, Necturus maculosus

Hypophysectomized male mud puppies ( Necturus maculosus) adapted to fresh water exhibited hyponatremia and hypocalcemia which were alleviated by ovine prolactin injections. However, if the animals were adapted to 0.6% sodium chloride solution, hypophysectomy produced hypocalcemia but not hyponatremia. These data suggest that mud puppy pituitary glands are specifically involved in calcium regulation in addition to their involvement in sodium regulation. Injection of ovine prolactin produced hypercalcemia and hypernatremia in intact mud puppies adapted to 0.6% sodium chloride solution containing high levels of calcium. However, the hormone had no significant effect on plasma calcium or sodium values in animals adapted to low-sodium fresh water with or without addition of calcium.

Effects of prolactin on hypophysectomized mud puppies Necturus maculosus.

Effects of prolactin on hypophysectomized mud puppies Necturus maculosus.