The development of an acth-induced renal glomerular lesion in Mus musculus. An ultrastructural study

Male house mice (Mus musculus) were injected with 4 international units of ACTH daily for 1, 2, 3 and 4 weeks and with four units daily for four weeks followed by 8 units for 8 days. Light microscopy of kidneys showed a glomerular lesion characterised by the expansion of the mesangium, deposition of PAS positive material in the glomerular mesangium and extraglomerular mesangium hypertrophy of juxtaglomerular cells and a successive increase in oil red-O staining material in the glomerulus. Electron microscopy revealed the progressive accumulation in the mesangial matrix of three morphologically distinct forms of deposits: amorphous, globular and particulate. The accumulation of amorphous deposit apparently is partially responsible for the increased PAS positive staining of the mesangium. Globular (and possibly particulate) deposit probably corresponds to the oil red-O positive material. The evidence suggests that the deposits are extraglomerular in origin, but their chemical nature is unknown.