Nocturnal Arginine Vasopressin Research Articles

AB033. Testosterone and nocturia

Nocturia is a major problem in the elderly and can be caused by a range of urologic and nonurologic conditions. Age-associated physiologic, structural, hormonal, and histologic changes play an important role in the increasing incidence of nocturia in elderly patients. Benign prostate hyperplasia (BPH) has been suggested as the main factor triggering nocturia, and therefore, efforts have focused on alleviating BPH through medical or surgical treatment. Although male lower urinary tract symptoms (LUTS) have traditionally been attributed to BPH, many evidences has shown that LUTS in some male patients might be derived from the bladder or systemic conditions. Recent investigations have reported that factors such as aging, late onset hypogonadism (LOH), and sleep disturbances are associated with nocturia. An increased prevalence of nocturia in elderly men is also caused by many factors other than BPH. Impaired kidney responsiveness to arginine vasopressin (AVP) and disrupted circadian nocturnal AVP secretion has been reported as a possible mechanism of nocturnal polyuria in older patients. Lack of sleep because of nocturia affects normal physiological actions in the human body, especially testosterone secretion. It is mostly secreted in the early morning and decreases to its minimum level after sleep. Therefore, sleep disturbances are believed to affect the pulsatile secretion of testosterone, and when sleep disturbances improve, testosterone secretion is expected to improve as well. Currently, it has not yet been revealed which of the following occurs first: nocturia-induced stress decreases testosterone levels or age induces decreased testosterone levels, which causes nocturia. Although the mechanism of action is still unknown, we suggest that desmopressin could correct disturbances of the circadian regulation of testosterone secretion. Because many factors are involved in testosterone and nocturia, further studies are needed to confirm our findings.

Nocturnal polyuria and nocturnal arginine vasopressin (AVP): A key factor in the pathophysiology of monosymptomatic nocturnal enuresis

To identify the relationship between nocturnal AVP deficiency, nocturnal polyuria (NP), and low urinary osmolality in children suffering of primary monosymptomatic nocturnal enuresis (NE). The study included 50 children (28 males and 22 females) with primary monosymptomatic NE and 30 non enuretic children of the same age group (controls). Night samples of blood and urine were obtained for AVP, blood osmolality, and urine osmolality. In addition, volume frequency charts, arousal threshold, and urodynamics were performed for these children. Twenty eight (56%) of the enuretic children were considered to have NP. Mean AVP level was 44.80 +/- 8.19 and 32.49 +/- 18.25 pg/ml while mean urine osmolality was 865.07 +/- 158.66 mOsm/kg and 700.06 +/- 84.42 mOsm/kg in controls and enuretic group respectively. These differences were highly significant. No significant difference was found between the controls and enuretics without NP. On the other hand, nocturnal AVP and urine osmolality were significantly lower in enuretics with NP when compared to both controls and enuretics without NP. Blood osmolality did not reach statistically significant difference between subgroups. Arousal threshold was significantly higher in enuretic children irrespective to NP. The timing for NE episodes were predominantly late in the night in NE children without NP while patients suffering of NE with NP typically experienced multiple incidents each night. We have shown that low nocturnal AVP and urine osmolality may play a role in the pathophysiology of enuretics with NP. This abnormality doesn't occur as an isolated disease as these children suffer from arousal defect as well.

Effect of DDAVP on nocturnal enuresis in a patient with nephrogenic diabetes insipidus

The case of an 8 year old boy with both nocturnal enuresis and nephrogenic diabetes insipidus is presented. Diagnosis of nephrogenic diabetes insipidus was based on a typical medical history,...

Circadian variation of plasma arginine vasopressin concentration, or arginine vasopressin in enuresis.

The objective of these studies was to determine a relationship between primary nocturnal enuresis and arginine vasopressin (AVP) secretion. The first study compared 24-h AVP secretion profiles of enuretic (n = 9) and non-enuretic children (n = 8). Blood samples were collected at 1-h intervals for 24 h. In the second study, nocturnal AVP secretion in group A (n = 40)--with low urinary osmotic pressure (UOP) and large nocturnal urine output (NUO)--was compared with that in group D (n = 11) with normal UOP and small NUO. Plasma AVP levels were measured at 30-min intervals, immediately after falling asleep until 06.00 the following morning. The results of the first study showed that the plasma AVP level was significantly lower (p < 0.05-0.001) in the enuretic group between 23.00 and 04.00. The second study showed that group A had significantly lower AVP levels (p < 0.05-0.001) than group D throughout the night. The mean AVP level during night sleep was 0.64 +/- 0.23 pg/ml in group A and 1.43 +/- 0.66 pg/ml in group D. The results of the first study suggest that decreased nocturnal AVP secretion is a cause of bedwetting. However, the results of the second study suggest that nocturnal enuresis cannot be explained by a decrease in nocturnal AVP secretion alone.

Subtypes in monosymptomatic nocturnal enuresis. II.

Lasting cure rates in monosymptomatic nocturnal enuresis (MNE), using the alarm, imipramine or desmopressin, have been quoted as 43%, 17% and 22%, respectively. The low cure rates in addition to the number of different treatments indicate insufficient knowledge of MNE. Only research on arginine vasopressin (AVP) levels and nocturnal enuresis is unique in attempting to find a group within the MNE population that could benefit from substitution therapy with desmopressin. AVP levels are restored or amplified during desmopressin treatment. However, low nocturnal AVP production with high nocturnal urine output may be indicative of a disturbance in circadian rhythm. Pre-clinical data suggest a role for melatonin in the regulation of endogenous AVP and in the regulation of the sleep/wake cycle.

The Arginine-Vasopressin Secretion Profile of Children with Primary Nocturnal Enuresis

Objective: The aim of this group of studies was to determine the relationship between primary nocturnal enuresis and arginine-vasopressin (AVP) secretion. Methods: The first study compared the 24-hour AVP secretion profiles of an enuretic group and a control group. Blood samples were collected every hour. In the second study, we compared nocturnal AVP secretion in group A, with low urinary osmotic pressure (UOP) and large nocturnal urinary volume (NUV), with that of group D, with normal UOP and small NUV. The plasma AVP level was measured at 30-min sampling intervals. In the third study, the change in nocturnal AVP secretion from before to after treatment was determined. Results: The plasma AVP level was significantly lower in the enuretic group from 23:00 through 04:00 h. The mean plasma AVP level was significantly lower in group A than in group D at all points of measurement. The mean nocturnal AVP level in group A (0.64 ± 0.23 pg/ml) was lower than that in group D (1.43 ± 0.72 pg/ml) (p < 0.0001). The mean nocturnal AVP level after treatment was significantly increased, from 0.47 pg/ml before treatment to 0.78 pg/ml after treatment (p = 0.01). However, a significant increase was noted in only 10 cases. Conclusions: These findings suggest that decreased nocturnal AVP secretion is one of the causes of bed-wetting. However, the improvement of bed-wetting was not solely due to the increased nocturnal AVP secretion.

Suprachiasmatic nucleus in a patient with multiple system atrophy with abnormal circadian rhythm of arginine-vasopressin secretion into plasma

We performed a quantitative investigation of arginine-vasopressin (AVP) immunopositive neurons in the suprachiasmatic nucleus (SCN), which is the endogenous clock of the brain of a patient with multiple system atrophy (MSA) who exhibited nocturnal polyuria associated with decreased urinary specific gravity and depression of nocturnal AVP secretion. Eleven age- and sex-matched subjects were used as controls. Although, the number of AVP-positive neurons was decreased in neither the supraoptic nucleus nor the paraventricular nucleus, the number of AVP-positive neurons in the SCN was decreased and gliosis was present in the SCN. The cytoplasmic area of AVP-immunopositive neurons in the SCN was smaller in the patient than in the control subjects. These findings raise the possibility that SCN is involved in MSA and the neurodegeneration in the SCN results in altered circadian rhythm of AVP secretion and nocturnal polyuria.

Circadian variations of ?synaptic? bodies in the pineal glands of Brattleboro rats

The function of the mammalian pineal gland is regulated primarily by the sympathetic system. Arginine-vasopressin (AVP) may also be involved in the regulation of pineal melatonin synthesis under experimental conditions. The present study was conducted in the AVP-deficient rat strain, the Brattleboro rat, to investigate whether the numbers and rhythms of pineal "synaptic" bodies in this strain are different from those found in intact rats. AVP or its non-vasoconstrictive analog, deamino-D-AVP, was also injected intra-arterially in Brattleboro or Sprague-Dawley rats to test whether this procedure influences "synaptic" body numbers. Brattleboro rats were killed at different time-points throughout the 24 h-cycle in March, June and September. "Synaptic" ribbons, spherules and intermediate structures were quantified and examined with regard to their intracellular location, with or without nocturnal AVP or D-AVP treatment. Numbers of ribbons were low during the day and high during the night (as in genetically intact rats), whereas spherules and intermediate structures numbers exhibited inconstant daily patterns. Night levels of "synaptic" ribbons were highest in June, lowest in March, whereas day levels did not differ significantly. No significant alterations in pineal "synaptic" body numbers were found following administration of AVP or D-AVP. Our results therefore indicate that AVP does not play a crucial role in the regulation of pineal "synaptic" body numbers in rats.