Renotropic Activity Research Articles

Serum renotropic activity and renal growth in spontaneously hypertensive rats

Studies performed in the 1950's suggested that a circulating factor controlling renal growth (renotropin) could contribute to hypertension. However, no assay was available to prove its existence. Recently, different assays have been able to demonstrate the presence of a circulating renotropic factor following unilateral nephrectomy in rats. Therefore, we investigated certain aspects of renal growth in SHR, especially serum renotropic activity, and compared these with the same parameters in three strains of normotensive rats (SD, NWR, and WKY). Renal slice and renal DNA synthesis in response to unilateral nephrectomy were not unusual in SHR compared to other strains previously studied. Sera and renal extracts from young SHR following unilateral nephrectomy compared to sera and renal extracts from sham-operated SHR stimulated 3H-thymidine incorporation into the DNA of renal fragments. This pattern was similar to findings when sera and renal extracts from unilaterally nephrectomized SD were investigated, but the sera and extracts from SHR may have shown greater overall stimulation. Interestingly, a relative increase in renotropic activity was found in the serum of untouched SHR (11.1% +/- 1.7 (SEM), P less than 0.001) but not untouched NWR, SD, and WKY. The greatest renotropic activity in SHR was found at 6 to 16 weeks of age (13.5% +/- 2.1 (SEM), P less than 0.001). The previously reported activator found in renal tissue after unilateral nephrectomy was not found to be increased in untouched SHR. No studies were performed on SHR greater than 25 weeks of age. As a first approximation, our investigations are consistent with a previously hypothesis that renotropin may play some role in hypertension.

Partial purification and characterization of a renotropic fraction from ovine pituitaries.

It has been previously established that hypophysectomy leads to renal atrophy in rats and that a crude pituitary-derived fraction is effective in restoring kidney weight to the level expected for intact animals of the same body weight. This paper reports that considerable purification of the crude renotropic fraction from ovine pituitaries has been achieved and that the purified fraction is capable of restoring kidney weights of hypophysectomized castrated rats to normal values. For example, after five daily subcutaneous injections (135 micrograms/day) there were significant increases in dry kidney weight and total renal protein and DNA. The pituitary-derived fraction was devoid of somatotropin, contained only trace amounts of corticotropin, gamma-lipotropin, vasopressin, and prolactin, and had only low levels of thyrotropin and follitropin. Daily injections of prolactin, thyrotropin, and follitropin in doses of 20 micrograms each failed to stimulate renal growth in hypophysectomized rats. Thus, it seems highly unlikely that these factors are responsible for the observed renal hyperplasia after treatment with the pituitary fraction. The purified renotropic fraction had an isoelectric pH between 8 and 9. On polyacrylamide gel electrophoresis in the presence of detergent and a reducing agent, the renotropic fraction exhibited two major bands and one minor band with mobilities that corresponded to those of a standard lutropin preparation. The renotropic fraction exhibited considerable crossreactivity with an antiserum directed against the lutropin alpha subunit, suggesting the presence of the common glycoprotein hormone subunit. Moreover, the purified fraction stimulated steroid production by Leydig tumor cells in vitro. It is noteworthy, however, that standard ovine lutropin at 135 micrograms/day failed to exhibit renotropic activity in hypophysectomized castrated rats, although effects were noted at twice that dose. It appears that the renotropic activity represents a pituitary substance that can be separated from lutropin only with difficulty.

Evidence for Renotropic Activity in Ovine Pituitaries*

A linear relationship was found for kidney weight vs. body weight in both intact and hypophysectomized male Sprague-Dawley rats, weighing 75–150 g; however, kidney weight was greater for a given body weight in intact animals. A partially purified extract of ovine pituitaries was prepared which had the heretofore undescribed property of stimulating renal growth in hypophysectomized animals to the level expected for intact rats of similar size. When rats, hypophysectomized 6 days previously, were given 10 daily injections of the pituitary extract, which was analyzed for GH, ACTH, and LH content, renal weight increased significantly. In contrast, kidney size in other hypophysectomized animals treated with a quantity of GH plus ACTH similar to that found in the extract did not increase beyond that expected for a hypophysectomized rat of comparable size. A possible indirect action of LH in the extract via androgen production was excluded by demonstrating that the extract produced similar renal growth in both h...

Appraisal of certain factors influencing compensatory renal hypertrophy.

ArticleAppraisal of Certain Factors Influencing Compensatory Renal HypertrophyMelvin A. Block, Khalil G. Wakim, and Frank C. MannMelvin A. BlockFrom the Division of Experimental Medicine, Mayo Foundation, University of Minnesota, Rochester, Minnesota, Khalil G. WakimFrom the Division of Experimental Medicine, Mayo Foundation, University of Minnesota, Rochester, Minnesota, and Frank C. MannFrom the Division of Experimental Medicine, Mayo Foundation, University of Minnesota, Rochester, MinnesotaPublished Online:31 Dec 1952https://doi.org/10.1152/ajplegacy.1952.172.1.60MoreSectionsPDF (1 MB)Download PDF ToolsExport citationAdd to favoritesGet permissionsTrack citations ShareShare onFacebookTwitterLinkedInWeChat Previous Back to Top Next Download PDF FiguresReferencesRelatedInformation Cited ByDevelopmental determinants of recovery after relief of partial ureteral obstructionKidney International, Vol. 33, No. 4Renotrophic factors in urineKidney International, Vol. 23, No. 4Serum renotropic activity and renal growth in spontaneously hypertensive ratsKidney International, Vol. 23, No. 4Upper Urinary Tract ObstructionSome General Considerations in the Surgical Treatment of Renal and Ureteric StoneCirculatory retention of urinary factors as a stimulus to renal growthKidney International, Vol. 12, No. 5Compensatory and Obligatory Renal Growth in Babies and AdultsANZ Journal of Surgery, Vol. 44, No. 4Inhibition of compensatory renal growth by ureterocaval fistulaJournal of Surgical Research, Vol. 9, No. 3Renal Na-K ATPase Relationship to Total Functional Renal MassNature, Vol. 218, No. 5137Über die (aseptische) HarnstauungsniereExamination of Growth-Mediated Changes in Hemodynamics and Tubular Transport of Sodium, Glucose and Hippurate after Nephrectomy5 August 2009 | Scandinavian Journal of Clinical and Laboratory Investigation, Vol. 22, No. 4Compensatory Renal Hypertrophy in Parabiotic RatsJournal of Urology, Vol. 98, No. 5Kidney Function Before, During and After Compensatory HypertrophyJournal of Urology, Vol. 98, No. 1The Stimulus to Hypertrophic GrowthPhysiological factors affecting compensatory renal hyperplasia in the ratJournal of Experimental Zoology, Vol. 145, No. 3The kidney in health; the nephron in diseaseThe American Journal of Medicine, Vol. 28, No. 1The Effect of Cortisone on Experimental Hydronephrosis Following Ureteral LigationJournal of Urology, Vol. 78, No. 4Physiology of the Human Solitary KidneyJournal of Urology, Vol. 78, No. 2Concepts of Ureteral PhysiologyJournal of Urology, Vol. 74, No. 3 More from this issue > Volume 172Issue 1December 1952Pages 60-66 Copyright & PermissionsCopyright © 1952 by American Physiological Societyhttps://doi.org/10.1152/ajplegacy.1952.172.1.60History Received 22 September 1952 Published online 31 December 1952 Published in print 31 December 1952 Metrics