Analyses of renal medullary lipid droplets from normal, hydronephrotic, and indomethacin treated rabbits

Comai, Karen; Farber, Saul J.; Paulsrud, John R.

doi:10.1007/bf02532360

Cited by 50 publications

(9 citation statements)

References 31 publications

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“…A marked increase in the number and the triglyceride content of the renal medullary interstitial cell lipid droplets and a decreased rate of PGF, synthesis have been observed with either ureter obstruction or indomethacin treatment in rabbits (11,12). Contradictory data, however, are available in the rat (13), where a reduction of lipid granularity of interstitial cells was observed with indomethacin.…”

Section: Resultsmentioning

confidence: 99%

Exaggerated prostaglandin biosynthesis and its influence on renal resistance in the isolated hydronephrotic rabbit kidney.

Nishikawa¹,

Morrison²,

Needleman³

1977

J. Clin. Invest.

155

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A B S T R A C T Basal and hormone-stimulated prostaglandin biosynthesis was compared in isolated perfused rabbit kidneys with and without ureteral obstruction. At 72 h there was enhanced responsiveness to bradykinin in the ureter-obstructed hydronephrotic kidney. The amount of prostaglandin-like substance released from the perfused kidneys by 25 ng of bradykinin was 533±+ 163 ng from the ureter-obstructed, 28+4 ng from the contralateral, and 26+3 ng from the normal kidney. The enhanced response was also noted with angiotensin II and with norepinephrine. This exaggerated responsiveness by the ureter-obstructed kidney could not be explained by decreased prostaglandin (PG) destruction or by decreased renal peptide inactivation (bradykinin or angiotensin). There was no enhanced PG biosynthesis with exogenous arachidonate, suggesting there was no increase in cyclo-oxygenase activity in the ureter-obstructed kidney. Renal tubular transport of PG from medulla to cortex was apparently not essential for the enhanced PG biosynthesis to hormone stimulation since the same exaggerated responses were noted during perfusion with the ureter ligated. The cyclo-oxygenase inhibitor, indomethacin, increased basal perfusion pressure in the obstructed kidney and enhanced the magnitude and duration of the renal vasoconstriction produced by angiotensin II in the hydronephrotic kidney. These results suggest that the local exaggerated biosynthesis of PG may be occurring in the cortical resistance vessels and may be important to the alteration in blood flow and excretory function that occur in ureteral obstruction.

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Section: Resultsmentioning

confidence: 99%

Exaggerated prostaglandin biosynthesis and its influence on renal resistance in the isolated hydronephrotic rabbit kidney.

Nishikawa¹,

Morrison²,

Needleman³

1977

J. Clin. Invest.

155

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“…These highly specialized cells exist in high density in the renal medulla and papilla (16,17), and contain large amounts of arachidonic acid, the precursor of PGE2 biosynthesis (18).…”

mentioning

confidence: 99%

Prostaglandin biosynthesis by rabbit renomedullary interstitial cells in tissue culture. Stimulation by angiotensin II, bradykinin, and arginine vasopressin.

Zusman¹,

Keiser²

1977

J. Clin. Invest.

335

117

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A B S T R A C T Rabbit renomedullary interstitial cells were isolated and grown in tissue culture. These cells synthesize 0.8 ng ofprostaglandin E2 (PGE2) per microgram cellular protein per hour in monolayer tissue culture; prostaglandins A2 and F2x (PGA2 and PGF2c) biosynthesis was 10 and 5% of PGE2 biosynthesis, respectively. Arachidonic acid markedly stimulated the production of PGE2 and PGFax, with conversion rates of 0.24 and 0.02%o/h, respectively. Angiotensin II, hyperosmolality, bradykinin, and arginine vasopressin each stimulated PGE2 biosynthesis; maximum stimulation was 20, 3.7, 3.6, and 3.2 times basal production, respectively. PGE2 biosynthesis by the renomedullary interstitial cells was inhibited by isoproterenol, potassium, nonsteroidal anti-inflammatory agents (indomethacin, naproxen, ibuprofen, suprofen, meclofenamate, and acetylsalicylic acid), mepacrine (a phospholipase inhibitor), hydrocortisone, and cortisone.The rabbit renomedullary interstitial cell in tissue culture is a model system for the study of hormonal regulation of PGE2 biosynthesis. (6)(7)(8)(9). PGE has been shown to antagonize the effect of antidiuretic hormone in the toad urinary bladder (10, 11), whereas indomethacin, a potent prostaglandin synthetase inhibitor, potentiates antidiuretic hormone in in vitro and in vivo studies (12-14).The renal medullary interstitial cell is the major site of prostaglandin biosynthesis within the kidney (15). These highly specialized cells exist in high density in the renal medulla and papilla (16,17), and contain large amounts of arachidonic acid, the precursor of PGE2 biosynthesis (18).To study the production of prostaglandins by renal interstitial cells independent of the many interlocking systems which characterize renal function, we have grown rabbit renal interstitial cells in tissue culture. The rabbit renomedullary interstitial cell in tissue culture is a model system for the study of the molecular events associated with hormonal stimulation of PGE2 biosynthesis. The characterization of prostaglandin production by these cells and the effects of a number of vasoactive peptides, hormones, physiologic stimuli, and drugs on PGE2 biosynthesis comprise this investigation. Effect of cellular growth on PGA, PGE, and PGF biosynthesis by rabbit renal interstitial cells in tissue culture. Trypsin-dispersed cells from 75-cm2 flasks were pooled and replicate 25-cm2 flasks containing 5 ml of fresh tissue culture medium were inoculated. Tissue culture medium was changed at 24-h intervals. At each 24-h interval, two flasks were scraped to remove the cells from the plastic surface, and the cellular protein was determined by the method of Lowry et al. (23), with bovine serum albumin as the standard. METHODSCharacterization of the factors affecting prostaglandin biosynthesis by renal interstitial cells in tissue culture. Before the study of the effects of vasoactive substances and prostaglandin synthesis inhibitors on prostaglandin biosynthesis, the effects of osmolality, time of incubation, sodium, ...

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“…Comai et al [2,3] showed a decrease in PGF2a synthesis of hydronephrotic rabbits. However, in the present study, renal PGF2a remained significantly unchanged.…”

Section: Discussionmentioning

confidence: 99%

“…There have been several studies on some aspects of renal PGs in hydronephrosis [1][2][3][9][10][11]. Thus, Olsen et al [11] showed that an increased intrapelvic pressure stimu lated renal PG activity.…”

Section: Introductionmentioning

confidence: 99%

Studies on Intrarenal Prostaglandins

Iihoshi¹,

Mitsuzaki²,

Tsuruta³

et al. 1978

Kidney Blood Press Res

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Prostaglandins (PGs) E₂ and F_2α in the rabbit kidney were determined in order to study the effects of unilateral ureteral occlusion for periods up to 6 weeks. A significant increase of PGE₂ concentration in the inner medulla of the obstructed kidney was always observed after ureteral occlusion of more than 24 h. In the contralateral kidney, PGE₂ in the inner medulla gradually decreased in proportion to the period of ureteral occlusion. The present results suggest that the enhanced PGE₂ may be a protective mechanism initiated to overcome the renal vasoconstriction after unilateral ureteral occlusion.

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Analyses of renal medullary lipid droplets from normal, hydronephrotic, and indomethacin treated rabbits

Cited by 50 publications

References 31 publications

Exaggerated prostaglandin biosynthesis and its influence on renal resistance in the isolated hydronephrotic rabbit kidney.

Exaggerated prostaglandin biosynthesis and its influence on renal resistance in the isolated hydronephrotic rabbit kidney.

Prostaglandin biosynthesis by rabbit renomedullary interstitial cells in tissue culture. Stimulation by angiotensin II, bradykinin, and arginine vasopressin.

Studies on Intrarenal Prostaglandins

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