Hypothalamic neuropeptides as biomarkers of diabetes insipidus.

N. Katamadze*^a (Dr), K. Fargieva^a (Dr), A. Shutova^a (Dr), E. Pigarova^a (Dr), L. Dzeranova^a (Dr)

^a Endocrinology Research Center, Moscow, RUSSIAN FEDERATION

* nincho.1994@mail.ru

Introduction: Diabetes insipidus (DI) is a form of polyuria-polydipsia syndrome and is characterized by hypotonic polyuria (excessive urination; >50 ml/kg body weight/24 h) and polydipsia (excessive drinking; >3 l/day) . Nephrogenic diabetes insipidus (NDI) is caused by the inability of the kidneys to concentrate urine in response to vasopressin.

Aim: The aim of our case report is to present the patient with NDI and to report the data on physiological changes in hypothalamic neuropeptides such as copeptin, oxytocin, apelin, brain natriuretic peptide (BNP) in patient with NDI.

Material and methods: 21-year-old male patient was admitted to the hospital with chief complaint of increased thirst and urinary frequency.

Results: In accordance with the results of indirect water-deprivation test NDI was diagnosed in our patient due to maximum urine osmolality of less than 76 mOsm/kg, plasma osmolality 302 mOsm/kg, maximum plasma sodium was 148 mmol/l, and no change in urine osmolality after administration of 2 mcg of s.c. desmopressin. Copeptin, oxytocin, apelin, BNP after 8-hour fluid restriction accounted for: 0.844 ng/ml (0.178-2.578 ng/ml), 5.694 ng/ml (0-12.821 ng/ml) ,1.476 ng/ml, (0.620-2.095 ng/ml),1225.86 pg/ml (646.3-2033.4 pg/ml) and at the peak of dehydration (for 16 hours) accounted for: 1.058 ng/ml, 6.176 ng/ml, 1.346 ng/ml, 973.93 pg/ml.

Conclusion: Obtained data can later be used for differential diagnostic procedures for the syndrome of polydipsia-polyuria. Our data confirms commensurate increase in the levels of copeptin and oxytocin with a reciprocal decrease in the concentrations of apelin and BNP against the background of additional dehydration.

The author has declared no conflict of interest.