Sertoli cell function in diabetic, insulin-treated diabetic, and semi-starved rats

It is well documented that long-term diabetes mellitus results in numerous deleterious consequences. However, considerable controversy exists concerning male reproductive function in diabetes. The purpose of this investigation was to study several endocrine parameters in diabetic male rats with emphasis on Sertoli cell function. Male Wistar rats were injected with streptozotocin and then either left untreated for 30 days or injected with insulin so as to prevent spillover of glucose into the urine. These two groups were compared with control animals that had only been injected with the vehicle for streptozotocin. Semi-starved control animals were included to determine if any of the potential endocrine alterations were related to body weight changes which occur in streptozotocin-injected rats. It was found that FSH, LH, PRL, and GH serum levels were reduced in diabetic animals. Only FSH was restored to normal by insulin injections. The testis, seminal vesicle, and epididymis weights were all reduced in diabetic animals. Insulin injections raised all organ weights; however, only testis weights were fully restored. Levels of epididymal ABP activity were found to be higher in diabetic animals when expressed per mg protein. Similar patterns of organ weight loss and hormonal alterations were observed in semi-starved rats. However, epididymal levels of ABP activity were unaffected by the semi-starved condition. While weight loss should be taken into consideration when interpreting cause and effect relationships in streptozotocin-treated animals, epididymal ABP levels appear to be well correlated with the altered metabolic state characteristic of diabetes.