Postnatal development of cyclooxygenase-2 in the rat kidney.
Prostaglandins are local mediators/modulators of kinin effects in the kidney. The prostaglandin G2/H2 synthase (cyclooxygenase, COX) is the key regulatory enzyme of prostanoid synthesis pathway. Two COX isoenzymes (constitutive or COX-1 and inducible or COX-2) have been described in the rat kidney. We have demonstrated the presence of COX-2 in a subset of thick ascending limb of Henle (TAL) cells in normal adult rats [Vio, C.P., Cespedes, C., Gallardo, P., Masferrer, J.L., 1997. Renal identification of cyclooxygenase-2 in a subset of thick ascending limb cells. Hypertension 30, 687-692]. The present work was designed to evaluate COX-2 during the postnatal development of the rat kidney. Kidneys from Sprague-Dawley rats were studied during postnatal days 5, 10, 15 days and adult (60 days) (n = 8 each group). Renal tissue was immunostained with specific antibodies against COX-2. COX-2 was observed exclusively in TAL. A small number of COX-2 cells were observed during early postnatal life, increasing from day 5 to 15, and decreasing thereafter to reach adult levels. During maximal expression, near 20% of TAL were COX-2 positive whereas in early postnatal period and adults, only 2% of TAL cells contain COX-2. This transient induction of COX-2 during development suggest that the enzyme is necessary for the postnatal development of the kidney. This change in COX-2 seems to correspond to a derepression of COX-2 gene expression secondary to low levels of glucocorticoids.
Vio
C P
CP
Departamento de Ciencias Fisiológicas, Facultad de Ciencias Biologicas, Pontificia Universidad Católica de Chile, Santiago. cvio@genes.bio.puc.cl
Balestrini
C
C
Recabarren
M
M
Cespedes
C
C
D000818:Animals; D000831:Animals, Newborn / Q000254:growth & development / Q000378:metabolism*; D051546:Cyclooxygenase 2; D007124:Immunoenzyme Techniques; D007150:Immunohistochemistry; D007527:Isoenzymes / Q000378:metabolism*; D007668:Kidney / Q000201:enzymology* / Q000254:growth & development*; D010544:Peroxidases; D011451:Prostaglandin-Endoperoxide Synthases / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley
D007527:Isoenzymes; D010544:Peroxidases; D051546:Cyclooxygenase 2; D011451:Prostaglandin-Endoperoxide Synthases