PHARMACOLOGY OF CYANATE. II. EFFECTS ON THE ENDOCRINE SYSTEM

¹ The Rockefeller University, New York, New York

The effect of sodium cyanate (NaNCO) in vitro on the biological activity of a series of protein and peptide hormones was studied. NaNCO, 100 mM, did not significantly affect the activities of growth hormone, adrenocorticotropic hormone, insulin, prolactin and human chorionic gonadotropin. Follicle-stimulating hormone was not affected by 10 mM NaNCO, but lost one-third of its activity when incubated with 100 mM NaNCO. The activities of thyroid-stimulating hormone, luteinizing hormone and antidiuretic hormone were virtually abolished by 100 mM NaNCO. Although the biological activity of thyroid-stimulating hormone was abolished in vitro, thyroid function in vivo was not affected by NaNCO administration to rats. In addition, ovulation was not blocked nor was pituitary luteinizing hormone activity affected by NaNCO administration. A prolonged anestrus, produced by the chronic administration of high doses of NaNCO, appeared to be due to a reduction in food intake and/or body water imbalance resulting from diuresis. The chronic administration of 25 mg/kg/day of NaNCO to rats had no effect on reproductive capacity and was not teratogenic. NaNCO induced a diuresis in the alcoholized (antidiuretic hormone suppressed) rat, whici suggests that the diuretic property of ^-NCO is not a result of the carbamylation of antidiuretic hormone in vivo, but is the result of a direct effect upon the kidney.