Pituitary growth hormone secretory granules in streptozotocin-induced diabetic rats.

The ultrastructural features of growth hormone (GH) secretory granules were observed by immuno-gold procedure in the anterior pituitary glands of streptozotocin (STZ)-induced diabetic rats. The diabetic state of rats induced by one injection of STZ was severely advanced at 10 months after the injection. The cytoplasmic organella were revealed to be poorly developed in GH-cells of the diabetic rats. The size of immunoreactive GH-granules of 10-months-old diabetic rats was smaller than that of sham-controls. The insulin therapy in the diabetic rats resulted in a considerable improvement in relation to the changes seen in the GH-cells, but the therapy did not return the profile of the granule size distribution to that of the control group.