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Polyamine metabolism in mouse kidney after administration of mercuric chloride
Abstract:
Testosterone administration to gonadectomized male mice, besides giving rise to a distinct hypertrophy of the kidneys, results in a large increase in renal ornithine decarboxylase activity and accumulation of polyamines. Experiments were performed to examine the effects of localized renal injury caused by mercuric chloride administration on the polyamine metabolism in the testosterone stimulated mouse kidney. A single injection of mercuric chloride resulted in severe damage of tubular epithelium primarily in the proximal convolutions situated in the cortex and outer medullary stripe. Although the injection of mercuric chloride to testosterone treated mice decreased the stimulation of ornithine decarboxylase activity it did not prevent the increase in the concentration of putrescine. The levels of spermidine as well as of RNA were elevated. These results may indicate early reperative growth following mercuric chloride administration. The observations are discussed in relation to the effects of 1,3-diaminopropane, another nephrotoxic agent on renal growth and polyamine metabolism.
Insights
Testosterone stimulates kidney growth and polyamine accumulation. Mercuric chloride injury in these mice reduced ornithine decarboxylase but increased putrescine and spermidine, suggesting repair processes.
Area of Science:
- Nephrology
- Molecular Biology
- Endocrinology
Background:
- Testosterone administration induces kidney hypertrophy and increases renal ornithine decarboxylase (ODC) activity and polyamine levels in male mice.
- Polyamines are crucial for cell growth and differentiation, and their metabolism is tightly regulated.
Purpose of the Study:
- To investigate the impact of localized renal injury, induced by mercuric chloride, on polyamine metabolism in testosterone-stimulated mouse kidneys.
- To understand the interplay between hormonal stimulation, nephrotoxicity, and renal repair mechanisms.
Main Methods:
- Gonadectomized male mice were treated with testosterone to stimulate kidney growth.
- Localized renal injury was induced using a single injection of mercuric chloride.
- Kidney tissue was analyzed for ornithine decarboxylase activity, polyamine concentrations (putrescine, spermidine), and RNA levels.
Main Results:
- Mercuric chloride caused severe tubular damage, primarily in the proximal tubules.
- In testosterone-treated mice, mercuric chloride administration decreased the stimulated ODC activity but did not inhibit the rise in putrescine concentration.
- Elevated levels of spermidine and RNA were observed post-injury.
Conclusions:
- Despite reduced ODC stimulation, the increase in putrescine and spermidine suggests active regenerative processes following mercuric chloride-induced renal injury in testosterone-primed kidneys.
- These findings provide insights into renal repair mechanisms and the role of polyamines in response to toxic insults, with implications for understanding nephrotoxic effects of agents like 1,3-diaminopropane.