Somatostatin analogue administration prevents increase in kidney somatomedin C and initial renal growth in diabetic and uninephrectomized rats.

In a previous study we demonstrated that the kidney content of somatomedin C was maximal one to two days after uninephrectomy or induction of diabetes, and that insulin treatment prevented an increase in kidney somatomedin C as well as kidney growth in diabetic animals. In the present study we have examined the effect of a somatostatin analogue on kidney somatomedin C and initial renal growth in the two experimental situations. The kidney hypertrophy in untreated diabetic animals amounted to 23% four days after streptozotocin injection and followed an increase in kidney somatomedin C content of 60% reaching the maximum after 48 h. In young and old uninephrectomized rats kidney growth was 19% and 16% after four days. In young animals a prompt increase of 50% in kidney somatomedin C was seen as reaching the maximum after 24 h, while the somatomedin C content in kidneys from old animals was maximal after 48 h (increase of 58%) in good accordance with the slightly slower kidney growth. The new findings of the present study are that administration of a long-acting somatostatin analogue (Sandostatin) effectively prevented the obligatory increase in kidney somatomedin C content as well as kidney growth both in experimental diabetes and after uninephrectomy. It is noteworthy that Sandostatin administration did not alter the metabolic state in diabetic animals indicating that the inhibition of kidney hypertrophy could not be attributed to improved metabolic control. The results thus support the concept that somatomedin C is involved in initial diabetic and post-nephrectomy renal growth.