Effects of prolactin on Na+K(+)-ATPase activity in the nephron during maturation in the rat.
The effect of prolactin (PRL) on renal Na+K(+)-ATPase was investigated in 7-d-old neonatal rats. Animals were treated by bromocriptine (Br; a blocker of endogenous PRL secretion), and the enzyme activity was compared with that of untreated controls. Na+K(+)-ATPase was determined in renal sections in the medullary thick ascending limb of Henle's loop and in the distal tubule by cytochemistry. In the distal tubule, Na+K(+)-ATPase activity was significantly lower in Br-treated animals than in controls (330 +/- 169 versus 558 +/- 146 pmol inorganic phosphate/mm/h, respectively); values did not differ in the medullary thick ascending limb of Henle's loop between Br-treated and control animals (132 +/- 74 versus 165 +/- 113 pmol inorganic phosphate/mm/h, respectively). In vitro effects of PRL were investigated by determining the enzyme activity after incubation of renal sections from Br-treated and untreated animals with different concentrations of PRL. Results suggest that PRL may affect renal Na+K(+)-ATPase activity in the distal tubule in the neonatal period but do not support a major role of PRL in the enzyme maturation.
Laborde
K
K
Department of Physiology, Hôpital Necker-Enfants Malades, Paris, France.
Bussieres
L
L
Dechaux
M
M
Shahedi
M
M
Sachs
C
C
D000818:Animals; D000831:Animals, Newborn; D001971:Bromocriptine / Q000494:pharmacology; D009399:Nephrons / Q000187:drug effects / Q000201:enzymology* / Q000254:growth & development; D011388:Prolactin / Q000037:antagonists & inhibitors / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains; D000254:Sodium-Potassium-Exchanging ATPase / Q000378:metabolism* / Q000502:physiology
D001971:Bromocriptine; D011388:Prolactin; D000254:Sodium-Potassium-Exchanging ATPase