-transparent.png){kind=logo}
The osmoregulatory responses to warmer temperatures and hormone treatment in cold-adapted (5 degrees C) Rana catesbeiana tadpoles and newly metamorphosed frogs were examined. Tadpoles transferred to 11 degrees C and 18 degrees C and left for 5 days lost 7% and 10% of their body weight. Plasma [Na+] was elevated 28% and 21%, respectively. Control (5 degrees C) animals maintained their body weight and plasma [Na+] constant. Daily treatment with either ovine prolactin (oPRL) or ovine growth hormone (oGH) prevented the weight loss and the increase in extracellular [Na+] that occurred when tadpoles were transferred to 18 degrees C. Neither propylthiouracil (PTU) nor arginine vasotocin (AVT) were effective in countering temperature-induced weight loss in tadpoles. Newly metamorphosed frogs transferred to 18 degrees C also lost weight; this was not prevented by daily treatment with saline, oPRL, oGH or PTU. However, in frogs treated daily with AVT, initial BW was regained by day 6. When warm-adapted (18 degrees C) tadpoles were treated daily for 18 days with saline, bPRL, bGH, thyroxine (T4), ergocornine, cortisol, or cortisol + T4, bPRL was most effective in retarding weight loss and maintaining body water content, whereas T4 + cortisol caused the greatest loss of weight and body water. By day 20, the correlations between weight loss and both body water content and hematocrit were highly significant. These data suggest that reported increases in plasma solute concentrations in larval amphibians may actually reflect decreases in extracellular fluid volume, rather than increased amounts of solutes, per se.
S C Brown, and
E A Horgan, and
L M Savage, and
P S Brown
November 1971,
Comparative biochemistry and physiology. B, Comparative biochemistry,
S C Brown, and
E A Horgan, and
L M Savage, and
P S Brown
January 1970,
Giornale di igiene e medicina preventiva,
S C Brown, and
E A Horgan, and
L M Savage, and
P S Brown
October 1977,
General and comparative endocrinology,
S C Brown, and
E A Horgan, and
L M Savage, and
P S Brown
April 1969,
Journal of ultrastructure research,
S C Brown, and
E A Horgan, and
L M Savage, and
P S Brown
May 1978,
Journal of applied physiology: respiratory, environmental and exercise physiology,
S C Brown, and
E A Horgan, and
L M Savage, and
P S Brown
February 1966,
Annals of physical medicine,
S C Brown, and
E A Horgan, and
L M Savage, and
P S Brown
May 1979,
Poultry science,
S C Brown, and
E A Horgan, and
L M Savage, and
P S Brown
January 1991,
Akusherstvo i ginekologiia,
S C Brown, and
E A Horgan, and
L M Savage, and
P S Brown
May 2002,
JPMA. The Journal of the Pakistan Medical Association,
S C Brown, and
E A Horgan, and
L M Savage, and
P S Brown
May 1974,
Acta physiologica Scandinavica,
