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M. quadriceps and diaphragm were studied in Wistar rats 2, 3, und 4 weeks after 5/6 nephrectomy. Control animals were sham operated and pair fed. In 10 mu transverse cryostat sections, the following histochemical reactions were performed: NADH-dehydrogenase, myofibrillar ATP-ase, modified trichrom stain, hematoxylin-eosin. Three fibre types (I, II, intermediate) were analysed quantitatively by planimetry. Sarcolemnal nuclei per unit area and fibre cross section area were determined. In muscle specimens from uremic animals, a uniform atrophy of all three fibre types could be demonstrated. In contrast to findings in man, preferential atrophy of one of the three fibre types, increase of sarcolemnal nuclei per fibre cross section area or structural abnormalities within single muscle fibres could not be detected. Neurogenic damage could be excluded (electrophysiology, sciatic nerve planimetry). The fibre changes point to a primary disturbance of muscle metabolism.

Thirtheen male patients with chronic renal failure undergoing regular dialysis treatment (2 X 8-10 hours/week) were treated with gonadotropins (HCG, Primogonyl) primarily 2 X 2,000 IU/week and later 2,000 IU/week. Before HCG administration and during 4-months HCG-therapy testosterone, dihydrotestosterone, Androstandiol, LH and FSH levels were determined by RIA-methods in 7-14 days intervals. Before HCG-application plasma testosterone levels were low and did not increase in the course of regular dialysis treatment. Derivates from testosterone like dihydrotestosterone and Androstandiol were elevated in plasma, presumbably because of accumulation in renal failure. LH-levels were slightly elevated on the average. FSH-levels showed a high individual variation but also seemed to be elevated on the average. HCG stimulation by exogenous HCG administration for short time resulted in a insufficient rise of testosterone levels as compared to normals. During prolonged HCG administration plasma testosterone levels increased to normal but dropped immediatly after cessation of therapy or reduction to less than 2,000 IU HCG twice/week. Body weight, plasma proteins, haematocrite and fertility did not improve significantly. These results indicate that in chronic renal failure androgen synthesis by testicular tissue is seriously impaired and does not improve under usual dialysis treatment. Feedback regulation of testosterone levels by increase of LH levels seems not to be sufficient although pituitary response is found to be normal. This may be explained by elevated levels of testosterone derivates which exert negative feedback effects.

In a 25-year-old woman with malignant hypertension based on primary nephrosclerosis, captopril, an oral inhibitor of angiotension I-converting enzyme, lowered blood pressure effectively, which had been resistant previously to other oral antihypertensive drugs. Concomitantly with the decrease of the high blood pressure, an increase of creatinine from 2.1 mg% to 8.5 mg% occurred. There is evidence that this increase of renal failure is a consequence of blood pressure reduction and is not caused by a toxic effect of captopril.