Amino acids release somatostatin-like immunoreactivity from isolated rat glomeruli

We reported recently the presence of somatostatin-like immunoreactivity (SLI) in the glomerulus of rat kidney. In the present study, we examined factors affecting SLI release from isolated rat glomeruli using a perifusion system. Perifusate containing a mixture of essential amino acids stimulated SLI release, while other hormonal agents such as parathyroid hormone, vasopressin, angiotensin II, bradykinin, epinephrine, PGE2, known to have direct actions on the glomerulus, had no discernible effect on SLI release. Addition of somatostatin to the perifusate did not affect either basal or angiotensin II-stimulated PGE2 release from isolated glomeruli. Our preliminary results demonstrate the stimulatory effect of mixed amino acids on somatostatin release from isolated glomeruli. Further studies are needed to elucidate the possible physiological significance of the present findings.