Hypothalamic diabetes insipidus

Two of ten patients taking long-term lithium therapy were thought to have hypothalamic diabetes insipidus, because of a positive response to desmopressin (615). 

Valtin H, Sawyer WH, Sokol HW (1965) Neurohypophyseal principles in rats homozygous and heterozygous for hypothalamic diabetes insipidus (Brattleboro strain). Endocrinology 77 701-706... 

The major indication of either type of diabetes insipidus is excessive urine production as much as 161 of urine per day. If adequate water is available for consumption, the disease is rarely fife-threatening. Hypothalamic diabetes insipidus can be treated with exogenous anti-diuretic hormone. 

Polyuric states are divided into three main categories (1) deficient AVP production (hypothalamic diabetes insipidus... 

Overnight water deprivation test (Box 50-9) If the ratio of urine to plasma osmolality is <1.5 at the end of the test, primary polydipsia is unlikeiy. Measure plasma and urine osmolalities and plasma ADH concentrations at the end of the test use these relationships to differentiate normal, nephrogenic, or hypothalamic diabetes insipidus, and psychogenic polydipsia. If urine osmoiahty is <400 mOsm/kg at the end of the test, give 5 U of aqueous vasopressin subcutaneously. If urine osmolality increases >10%, hypothalamic diabetes insipidus is probable if urine osmolality does not increase, nephrogenic diabetes insipidus is highly probable. 

It was recently reported that a posttrial injection of vasopressin may enhance later retention of inhibitory (passive)avoidance training in rats with hereditary hypothalamic diabetes insipidus that are not able to synthesize vasopressin. 6,77,78 This effect is time-dependent delayed injections do not affect later retention performance. Furthermore, in normal Wistar rats, intraventricular injections of antibodies to arginine-8-vasopressin 30 min prior to or immediately after the training trial produce amnesia in dose-dependent manner. ... 

Vasopressin and desmopressin are used in the treatment of pituitary diabetes insipidus. They are discussed in Chapter 37 Hypothalamic Pituitary Hormones. 

Schmale H, Ivell M, Breindl D, Darmer D, Richter D (1984) The mutant vasopressin gene from diabetes insipidus (Brattleboro) rats is transcribed but the message is not efficiently translated. EMBO J 3 3289-3293 Szot P, Dorsa DM (1992) Cytoplasmatic and nuclear vasopressin RNA in hypothalamic and extrahypothalamic neurons of the Brattleboro rat An in situ hybridization study. Mol Cell Neurosci 3 224-236... 

Hypothalamic ( central ) diabetes insipidus. This results from a deficiency in secretion of antidiuretic hormone from the posterior pituitary. Causes may include head trauma, infections or tumours involving the hypothalamus. 

The antidiuretic hormone is secreted according to a first-order neuroendocrine mechanism. A central nervous system neuron secretes the active polypeptide, which is transported in the blood to the target organ. This assumption is based on the experiments of Horsley and Clarke, who destroyed the hypothalamic nuclei without affecting the hypophysis itself by approaching the thalamus from above. These experiments demonstrated that destruction of the supraoptic nuclei or of the fiber tracts that lead from these nuclei to the posterior lobe was consistently associated with diabetes insipidus. In contrast, total hypophysectomy does not necessarily induce diabetes insipidus. 

---