[Osmoregulating effect of vasopressin with prolonged action on Brattleboro rats with hypothalamic diabetes insipidus].

The particularities of urine osmotic concentration depending on hormonal background of vasopressin were studied in rats. It was found that WAG and Brattleboro lines of rats characterized respectively by normal level and absence of endogenous vasopressin, possess interline correlation of urine osmolality (p = 0.86) in various conditions between the extreme hydrating and dehydratation. Concentrating level of WAG rats varies from 747 +/- 94 to 2936 +/- 128 mOsm/kg, but that of Brattleboro rats changes more within the 160 +/- 9 being twice lower as isotonicity to 1305 +/- 142 mOcm/kg. Urine concentrating goes up to 1391 +/- 76 mOcm/kg in Brattleboro rats already on the day of the action of exogenous vasopressin secreted from ALZET minipump, however, in spite of constant work of this minipump during 4 hrs a week, further increasing of urine osmolality was not observed in Brattleboro rats.

[Effects of Yiniao Recipe on serum antidiuretic hormone level and plasma ratio of cAMP to cGMP in rats with kidney-yang deficiency].

OBJECTIVE: To investigate the effects of Yiniao Recipe, a compound traditional Chinese herbal medicine, on contents of serum antidiuretic hormone, and plasma cyclic adenosine monophosphate and cyclic guanosine monophosphate in rats with kidney-yang deficiency. METHODS: Forty male Wistar rats were randomly divided into blank control group, untreated group, desmopressin (Minirin) group, low-dose Yiniao Recipe group and high-dose Yiniao Recipe group, with 8 rats in each group. Rats in the blank control group were injected with 0.2 mL normal saline, and rats in the other groups were given intramuscular injection of hydrocortisone 25 mg/kg, 1 time daily for 21 consecutive days; from the 8th day of injection, rats were given double distilled water, Minirin, and high- and low-dose Yiniao Recipe respectively for 30 days. Before and after treatment, 24-hour urine volume was observed, and serum antidiuretic hormone (AVP) as well as plasma cyclic adenosine monophosphate (cAMP) and cyclic guanosine monophosphate (cGMP) contents were detected by enzyme-linked immunosorbent assay. The cAMP/cGMP ratio and morphological changes in renal tissues were also observed. RESULTS: Compared with blank control group, 24-hour urine volume, serum AVP content and cAMP/cGMP ratio in the untreated group were decreased; compared with the untreated group, Minirin and Yiniao Recipe at low and high doses reduced 24-hour urine volume and increased serum AVP content and cAMP/cGMP ratio significantly (P<0.05 or P<0.01). There were no obvious pathological changes in renal tissue in all groups. CONCLUSION: Yiniao Recipe may reduce 24-hour urine volume by increasing serum AVP content and regulating the ratio of cAMP to cGMP in kidney-yang deficiency rats.

Comparison of two aquaretic drugs (niravoline and OPC-31260) in cirrhotic rats with ascites and water retention.

kappa-Opioid receptor agonists (niravoline) or nonpeptide antidiuretic hormone (ADH) V2 receptor antagonists (OPC-31260) possess aquaretic activity in cirrhosis; however, there is no information concerning the effects induced by the chronic administration of these drugs under this condition. To compare the renal and hormonal effects induced by the long-term oral administration of niravoline, OPC-31260, or vehicle, urine volume, urinary osmolality, sodium excretion, and urinary excretion of aldosterone (ALD) and ADH were measured in basal conditions and for 10 days after the daily oral administration of niravoline, OPC-31260, or vehicle to cirrhotic rats with ascites and water retention. Creatinine clearance, serum osmolality, ADH mRNA expression, and systemic hemodynamics were also measured at the end of the study. Niravoline increased water excretion, peripheral resistance, serum osmolality, and sodium excretion and reduced creatinine clearance, ALD and ADH excretion, and mRNA expression of ADH. OPC-31260 also increased water metabolism and sodium excretion and reduced urinary ALD, although the aquaretic effect was only evident during the first 2 days, and no effects on serum osmolality, renal filtration, and systemic hemodynamics were observed. Therefore, both agents have aquaretic efficacy, but the beneficial therapeutic effects of the long-term oral administration of niravoline are more consistent than those of OPC-31260 in cirrhotic rats with ascites and water retention.

Effect of surgical deafferentation of the hypothalamic supraoptic nucleus on urinary vasopressin levels in twenty-month-old rats.

Indices of water balance (daily water consumption, urine volume, and urine osmolality), and vasopressin (VP) urinary excretion were measured in 3-month-old (m.o.) and 20 m.o. F344 rats after neurosurgical lesion of noradrenergic afferents to the supraoptic nucleus (SON) in the medial forebrain bundle (mfb), in order to assess whether morphological denervation (21) was functionally effective. Lesion of the mfb was accomplished using a mechanical knife cut placed stereotaxically medial and caudal to SON. The experiment was performed three times. Morphological evaluation consistently indicated a marked depletion of noradrenergic afferents in SON after lesion placement. The effect of the lesion on daily excreted VP was assessed by paired t-test, using means of equal numbers of urinary VP measurements representing 13-15 days each pre- and postsurgically for each animal. The postsurgical interval for assessing the functional effect of the lesion was chosen based upon morphological evidence for mfb regeneration at 14 days (21). Three m.o. rats showed comparable urinary VP levels before (mean = 328.4 +/- 97.3 pg/24 hr/100 g b.wt., for 10 rats for 2 weeks) and after (354.7 +/- 63.0 pg/24 hr/100 g b.wt.) lesion placement. In 20 m.o. rats, overall mean postsurgical VP excretion was 199.4 +/- 44.8 pg for 15 rats for 2 weeks, compared with a presurgical mean of 343.2 +/- 86.2 pg/24 hr/100 g b.wt. Mean urine VP was lower in 20 m.o. rats in each of three experiments; VP levels after lesion in 3 m.o. rats was lower in 2, but higher in one experiment; mean differences were not statistically significant for treatment (lesion) effect.(ABSTRACT TRUNCATED AT 250 WORDS)

Antidiuretic hormone responses to eucapnic and hypocapnic hypoxia in humans.

Urinary excretion rate of antidiuretic hormone (UADHV) was studied in male volunteers in response to hypobaric hypoxia. The first series consisted of three groups. The chamber was decompressed to 465, 495, and 438 Torr during high-altitude (HA) exposure for groups I (n = 5), II (n = 5), and III (n = 4), respectively. In group I, the chamber air contained 3.77% CO2 to prevent alkalosis. The level of hypoxemia was similar in groups I and II. Mean 24-h UADHV was unchanged in group I, but increased 96% (P less than 0.05) and 180% (P less than 0.05) in groups II and III, respectively, on day 1 at HA and was normal during subsequent days at HA regardless of symptoms of acute mountain sickness. Shorter sampling intervals employed in a second series of experiments conducted at 495 Torr revealed a twofold increase in UADHV (P less than 0.05) 8-12 h after ascent in eight asymptomatic subjects; UADHV returned to base line within 9 h and remained low. The symptomatic subjects both had increased UADHV (3- and 8-fold from base line) between 2 and 4 h after ascent. Increased UADHV in asymptomatic subjects may be a result of the concomitant decrease in plasma volume, both of which appeared to be eliminated by CO2 supplementation.

Physiological responses to head-out immersion in water at 11 ATA.

Cardiorespiratory, thermal, and renal responses to a 30-min head-out immersion in 15 degree C water were studied at 1-ATA air and 11-ATA helium-oxygne environments in four male subjects wearing dry suits. Cardiorespiratory responses to immersion (reductions in heart rate, expiratory reserve volume, vital capacity, and thoracic impedance; and increases in stroke volume, cardiac output, and inspiratory capacity) were comparable at both pressures. However, thermal responses to immersion (a reduction in mean skin temperature and increases in skin heat flux and suit conductance) were significantly greater at 11 ATA compared to those at 1 ATA. The rate of urinary excretion of norepinephrine increased significantly during and after immersion at 11 ATA but not at 1 ATA. In contrast, the urinary excretion of epinephrine was not altered by pressure or immersion. The immersion diuresis was greater and lasted longer at 11 ATA than at 1 ATA although there was no difference in the endogenous creatinine excretion . This diuresis was accompanied by a significant natriuresis which was more marked at 1 ATA than at 11 ATA. At 1 ATA, the urinary excretion of both aldosterone and antidiuretic hormone (ADH) decreased during immersion. At 11 ATA, the rate of excretion of these hormones before immersion was lower compared to that at 1 ATA and did not change significantly during immersion. These results indicate that immersion in a hyperbaric helium-oxygen environment presents a greater cold stress than at 1-ATA air, and also that immersion diuresis and natriuresis at high pressure may be induced by a factor other than inhibition of aldosterone and ADH.

The ADH-reserve capacity in Brattleboro rats.

The water metabolism was studied in homo- and heterozygous Brattleboro rats suffering from hereditary hypothalamic diabetes insipidus. In homozygous Brattleboro rats the spontaneous water intake and urinary output and the diuretic reactions signficantly increased after water and salt loading. No antidiuretic activity was found in the urine, posterior pituitary or hypothalamus of these animals, and this state was not affected by hyperosmosis. For the heterozygous rats the spontaneous water intake and urinary output and the diuretic reaction exceed the respective control values, the posterior pituitary, the hypothalamus and the urine are of reduced antidiuretic activity and this activity is less mobilizable by hyperosmosis. It is concluded that the ADH-reserve deficiency is total in the homozygous Brattleboro rats, and partial in the heterozygotes. As a result of hyperosmosis, the vasopressin release is of a reduced extent, yet detectable in the heterozygotes.

Polyuria and imparied ADH release following medial preoptic lesioning in the rat.

Studies were carried out in the rat to detemine if hypothalamic lesions which caused polydipsia and polyuria had their effect mediated through an alteration of the ability of the neurohypophyseal system to release ADH. Rats with medial preoptic lesions hadincreased water intake while on ad libitum access to water and slightly impaired ability to conserve water following dehydration, but with no impairment of urine-concentrating ability. These were associated with an increase in plasma osmolality both during ad libitum fluid intake and after dehydration. Urinary ADH excretion was at leastas great as in shamoperated controls during ad libitum water intake, but failed to increase during dehydration in spite of a marked increase in plasma osmolality. Pituitary ADH content did not differ from control animals either during ad libitum water intake of after dehydration. Animals with lesions in the lateral preoptic and septal areas did not differ from control animals during ad libitum fluid intake and after dehydration even though lateral preoptic lesions produced polydipsia. In all animals, lesions were remote from the supraoptic nuclei, which showed no histological evidence of damage. It is concluded thatareas of the central nervous system away from the supraoptic nuclei are involved in the regulation of both water intake and ADH release.

[Interactions between a progestational derivative (norethisterone acetate) and ethinyl estradiol on urinary elimination of neurophysin, ocytocin, and vasopressin and on the blood level of neurophysin I and II in normal human beings]. / Interactions entre un dérivé progestatif (acétate de noréthistérone) et l'éthinyl oestradiol sur l'élimination urinaire de neurophysine, d'ocytocine et de vasopressine immunoréactives et sur le taux de neurophysine sérique I et II chez l'homme normal

PIP: Neurophysin 1 (a peptide associated with antidiuretic homone, ADH), ADH, and oxytocin were measured in serum or urine of 3 men who took 10 mcg ethinyl estradiol with 5 mg norethisterone acetate twice daily for 6 days and in 3 who took the estrogen only. Neurophysin in plasma was determined by radioimmunoassy, and individually by starch gel electrophoresis, extraction, and assay. Total urine neurophysin was measured by radioimmunoassy. ADH and oxytocin were quantitated by column chromatography and radioimmunoassy. With both steroids, there was no change in neurophysin, ADH, or oxytocin. Ethinyl estradiol alone increased urinary neurophysin from 112.3 to 595 ng/hour (n.s.), oxytocin from 41-132 ng/hour (p less than .005), and ADH from 9.7-57.2 ng/hour (p less than .01). As in pregnant women compared to normal women, estrogen treatment stimulated plasma neurophysin 1 more than neurophysin 2 in these subjects. These results confirm those found in rats.^ieng