Glomerular number and size in relation to age, kidney weight, and body surface in normal man

TLDR

Body surface area correlates significantly with metabolic rate. The number and size of glomeruli in normal, mature human kidneys were estimated by a direct and unbiased stereological method, the fractionator. The authors estimated an average of 617,000 glomeruli per kidney with a mean volume of 6.0 µm³, finding that glomerular number and size decrease with age and increase with kidney weight, while body surface area correlates with kidney weight and total glomerular volume but not with number, indicating that filtration capacity adapts to metabolic demand by altering glomerular size rather than number.

Abstract

Abstract The number and size of glomeruli in normal, mature human kidneys were estimated by a direct and unbiased stereological method, the fractionator. The number was 617,000 on average, and the mean size 6.0 M μm 3 . Both glomerular number and size showed significant negative correlation to age and significant positive correlation to kidney weight. Apparently, humans loose glomeruli with age. Body surface area correlated positively to kidney weight and total glomerular volume but not to number of glomeruli. Body surface area correlates significantly with metabolic rate (Robertson and Reid, Lancet, 1: 940–943, 1952). Thus, intraspecies adaptation of kidney filtration capacity to the metabolic demand is performed by changing the size of glomeruli, i. e., the number of glomeruli in individuals of a given species is independent of the metabolic rate.