Abstract
In 14 immature (30-45 day) Munich-Wistar rats with surface glomeruli accessible to micropuncture, glomerular capillary (PGC) and Bowman's space (PT) hydraulic pressures, efferent arteriolar oncotic pressure (ΠE), single nephron (SN)GFR, initial glomerular plasma flow rate (QA), afferent (RA) and efferent (RE) arteriolar resistances, and glomerular capillary ultrafiltration coefficient (Kf) were determined under euvolemic conditions. Results are compared with those from 14 adult (70-100 day) rats studied under similar conditions. (Mean ± SE, † P <.01)
Thus, mean values for PGC, PT and SNFF in immature were essentially the same as those in adult. Since the net force for ultrafiltration at the efferent end of the glomerular capillary network (given by PGC-PT-ΠE) was essentially zero in immature and adult alike, Kf was not a factor limiting SNGFR in either group. Instead, the lower values for SNGFR per gram kidney weight (KW) in immature than adult are primarily a consequence of lower QA/gKW, the latter due, at least in part, to markedly higher RA and RE. The causes for these higher resistances, whether structural or humoral, remains to be determined.
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Ichikawa, I., Brenner, B. 1072 FACTORS LIMITING GLOMERULAR FILTRATION RATE IN THE IMMATURE RAT. Pediatr Res 12 (Suppl 4), 542 (1978). https://doi.org/10.1203/00006450-197804001-01078
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DOI: https://doi.org/10.1203/00006450-197804001-01078