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Studies were conducted to evaluate inducible cyclooxygenase-2 expression in bladder during during fetal development and the expressions of cyclooxygenase-1 and 2 after obstruction. Cyclooxygenase-2 expression during early bladder development was found high but declined as gestation progressed. Results demonstrate that cyclooxygenase-2 expression is significantly enhanced by bladder outlet obstruction.

The distribution of the messenger RNAs of parathyroid hormone-related proteins (PTHrPs), PTH/PTHrP and the RaKCaR kidney calcium receptor was analyzed via reverse transcription-polymerase chain reaction (RT-PCR). RT-PCR analysis of complementary DNA from dissected rat nephron segments indicated the presence of RaKCaR messenger RNA (mRNA) in the medullary and cortical ascending limbs. On the other hand, PTHrP mRNA was expressed in the glomeruli and lower levels of the proximal convoluted tubules.

Yang, Tianxin, Daniel E. Michele, John Park, Ann M. Smart, Zhiwu Lin, Frank C. Brosius III, Jurgen B. Schnermann, and Josephine P. Briggs. Expression of peroxisomal proliferator-activated receptors and retinoid X receptors in the kidney. Am. J. Physiol. 277 (Renal Physiol. 46): F966-F973, 1999.--The discovery that 15-deoxy-[[Delta].sup.12,14]-prostaglandin [J.sub.2] (15d-[PGJ.sub.2]) is a ligand for the [Gamma]-isoform of peroxisome proliferator-activated receptor (PPAR) suggests nuclear signaling by prostaglandins. Studies were undertaken to determine the nephron localization of PPAR isoforms and their heterodimer partners, retinoid X receptors (RXR), and to evaluate the function of this system in the kidney. PPAR[Alpha] mRNA, determined by RT-PCR, was found predominately in cortex and further localized to proximal convoluted tubule (PCT); PPAR[Gamma] was abundant in renal inner medulla, localized to inner medullary collecting duct (IMCD) and renal medullary interstitial cells (RMIC); PPAR[Beta], the ubiquitous form of PPAR, was abundant in all nephron segments examined. RXR[Alpha] was localized to PCT and IMCD, whereas RXR[Beta] was expressed in almost all nephron segments examined. mRNA expression of acyl-CoA synthase (ACS), a known PPAR target gene, was stimulated in renal cortex of rats fed with fenofibrate, but the expression was not significantly altered in either cortex or inner medulla of rats fed with troglitazone. In cultured RMIC cells, both troglitazone and 15d-[PGJ.sub.2] significantly inhibited cell proliferation and dramatically altered cell shape by induction of cell process formation. We conclude that PPAR and RXR isoforms are expressed in a nephron segment-specific manner, suggesting distinct functions, with PPAR[Alpha] being involved in energy metabolism through regulating ACS in PCT and with PPAR[Gamma] being involved in modulating RMIC growth and differentiation. 15-deoxy-[Delta]12,14-prostaglandin [J.sub.2]; reverse transcription-polymerase chain reaction; acyl-coenzyme A synthase; microdissected nephron segments

To provide a frame of reference for studies of renal divalent cation and phosphate metabolism, we assessed the cellular localization of kidney calcium receptor (RaKCaR), parathyroid hormone- related protein (PTHrP), and parathyroid hormone/ parathyroid hormone-related protein (PTH/PTHrP) receptor mRNA. The studies used using reverse transcription-polymerase chain reaction (RT-PCR) applied to cDNA prepared from dissected rat nephron segments and from primary cultures of mouse juxtaglomerular granular cells. With species-specific primers, PCR products of expected size were obtained for RaKCaR (967 bp), PTHrP (420 bp), and PTH/PTHrP receptor (817 bp), with product identity being confirmed by restriction digestion. RaKCaR mRNA was found in medullary and cortical thick ascending limbs (MTAL and CTAL, respectively), the macula densa-containing segment, distal convoluted tubules (DCT), and, to a lesser extent, in cortical collecting ducts (CCD). It was not found in glomeruli, proximal convoluted and straight tubules (PCT and PST, respectively), outer and inner medullary collecting ducts (OMCD and IMCD, respectively), or in juxtaglomerular granular cell isolates. PTHrP mRNA was predominantly expressed in glomeruli and at lower levels in PCT and the macula densacontaining segment but was not detectable in CTAL, MTAL, DCT, and CD segments. Presence of PTH/PTHrP receptor mRNA was demonstrated in glomeruli, PCT, PST, CTAL, MTAL, and DCT but not in CD segments. These results suggest that the function of TAL and DCT cells, in addition to being affected by PTH, may be directly altered by extracellular divalent cations through RaKCaR and that PTHrP may act in the glomerulus and proximal tubule as an autocrine or paracrine regulator of hemodynamics and phosphate transport. [ABSTRACT FROM AUTHOR]

Integrins mediate cell-cell and cell-extracellular matrix interactions and play key roles in development. beta(6) integrin expression has been demonstrated in human fetal kidney at a higher level than in the adult, making beta(6) integrin a marker of interest for the study of development of the nephron. The aims of this study were to determine the cDNA sequence for the mouse beta(6) integrin and to characterize beta(6) integrin expression in the developing mouse kidney. Two embryonic mouse kidney cDNA libraries were screened, and the coding region was sequenced. The mouse beta(6) nucleotide coding region sequence shows 82% nucleotide identity to the human sequence. The putative amino acid sequence has 89.5% identity to human beta(6) integrin and contains many conserved domains. By reverse transcription-PCR, beta(6) integrin mRNA expression is very low at 11 d of gestation in the mouse, increases dramatically by E14 and E17 (20-fold, normalized for increases in ss actin), and plateaus by 2 wk of age. beta(6) integrin expression is induced 15- to 20-fold after 5 d in metanephric explant culture. Reverse transcription-PCR of adult rat microdissected nephron segments demonstrates ss(6) integrin mRNA expression in proximal tubule, cortical thick ascending limb, distal nephron segments (inner and outer medullary collecting ducts), and macula densa-containing segments. Lectin-peroxidase and in situ colocalization studies demonstrated expression of ss(6) integrin mRNA in developing proximal tubules and thick ascending limb. Culture of mouse metanephric kidneys with antisense oligonucleotides to beta(6) integrin resulted in inhibition of ureteric bud branching and complete lack of mesenchyme condensation. These studies demonstrate a high homology between the human and mouse beta(6) integrin sequence, a different pattern of expression in the developing mouse kidney compared with the primate kidney, and abnormal metanephric development in culture in the absence of beta(6) integrin. These findings suggest an important role for beta(6) integrin in normal development of the mouse kidney.