Effects of prolactin on water balance and kidney function in bullfrog tadpoles.
In four experiments of similar design, stage III-XII bullfrog tadpoles were treated for 5-13 days with either 10 micrograms/day ovine prolactin (PRL) or 10 microliters/day saline (0.7% NaCl). In all cases, saline-treated tadpoles lost ca. 10% of their body weight, whereas PRL-treated animals either maintained their weight or gained slightly. Compared with controls, PRL-treated tadpoles showed a significantly higher water content and a 10-20% increase in inulin space (= extracellular volume). PRL treatment also significantly decreased plasma [Na+] (but not total extracellular [Na+]), and the rates of renal inulin clearance (= glomerular filtration rate) and urine production. PRL-treated tadpoles showed significant retention of the water taken up in response to a salt load. These data suggest that the PRL-induced weight gain observed in bullfrog tadpoles is accompanied by major changes in renal function and the size, water content, and sodium concentration of the extracellular fluid compartment.
Brown
P S
PS
Department of Biology, Siena College, Loudonville, New York 12211.
Murphy
M J
MJ
Brown
S C
SC
D000818:Animals; D001834:Body Water / Q000187:drug effects*; D007668:Kidney / Q000187:drug effects / Q000502:physiology*; D011388:Prolactin / Q000494:pharmacology*; D011892:Rana catesbeiana / Q000502:physiology*
D011388:Prolactin