Prenatal Development of the Guinea Pig Kidney Quantitative And Qualitative Morphology

Abstract

The normal prenatal development of the guinea pig kidney was investigated utilizing quantitative and qualitative histologic methods and microdissection technique during the last of the gestation period (day 46 to day 66). From day 46 up to day 55 of gestation, the differentiation of the newly formed nephrons within the superficial renal cortex was the main morphologic change. The number of glomeruli increased markedly during this period, while both the glomerular volume and the proximal tubular length of the juxtamedullary nephrons did not change. Several generations of glomeruli that surrounded by tubule sections were localized in the deeper cortex between day 55 and 60 of the gestation. Later (day 61 to 66) this region showed inward-growing loops in the area that became medullary rays. The tubular density as well as their diameters gradually increased in all cortical layers. From day 55 onward, the major morphologic change was the marked lengthening of the proximal tubules of the juxtamedullary and superficial nephrons. A subcapsular nephrogenic zone completely disappeared around day 56 to day 60 of gestation; indicating completion of nephrogenesis.