Effect of ovariectomy and treatment with ovarian steroids on vasopressin release and fluid balance in the rat

1990 ◽  
Vol 124 (2) ◽  
pp. 277-284 ◽  
Author(s):  
K. Peysner ◽  
M. L. Forsling
Keyword(s):  
Water Intake ◽  
Fluid Balance ◽  
Plasma Concentrations ◽  
Plasma Osmolality ◽  
Control Group ◽  
Oestrogen Treatment ◽  
Vasopressin Release ◽  
Plasma Vasopressin ◽  
Progesterone Treatment ◽  
Food And Water Intake

ABSTRACT Plasma vasopressin concentrations have previously been shown to vary during the oestrous cycle of the rat, being highest on the morning of pro-oestrus and lowest on dioestrus day 1. To determine the effect of gonadal steroids on vasopressin secretion and fluid balance, mature rats were ovariectomized and given oestrogen, progesterone or vehicle alone s.c. for periods of up to 16 days. Plasma vasopressin concentrations fell after ovariectomy and this was reflected in an increase in 24-h urine volume. The normal increase in plasma vasopressin concentrations seen over daylight hours was also suppressed. The change in vasopressin concentrations observed on steroid treatment depended upon both the dose and the duration. High doses of oestrogen were associated with a fall in plasma vasopressin, probably as a result of fluid retention. Thus, of an initial group of rats given silicone elastomer implants containing 50, 500 or 1000 μg oestradiol in oil, plasma vasopressin concentrations were reduced after 7 days treatment with 1000 μg oestradiol implants in association with reduced plasma sodium concentrations. Daily s.c. injections of 100 μg oestradiol benzoate/100 g body weight produced an immediate small increase in plasma vasopressin concentrations, but by 14 days the plasma concentrations of 0·7 ± 0·16 pmol/l (mean ± s.e.m.) had fallen significantly and were less than those in the vehicle-treated group (1·2± 0·26 pmol/l). However, after treatment for 14 days with implants containing only 50 μg oestradiol, plasma vasopressin concentations were higher compared with the group receiving vehicle alone, despite the fact that the plasma osmolality was lower in the latter group, suggesting a long term resetting of the osmoreceptors. Progesterone treatment with two implants containing 17·5 mg progesterone in oil was associated with an initial suppression of plasma vasopressin concentrations, but 16 days after the implant the plasma concentrations were higher than in the control group. Neither oestrogen nor progesterone restored the vasopressin concentrations to those seen in the intact animal. Oestrogen treatment resulted in a reduction in food and water intake, whereas progesterone treatment produced an initial increase in food and water intake, and a fall in plasma osmolality which could account for the reduced plasma vasopressin. This was followed by an increase in urine flow over days 6 to 15. Thus ovariectomy had a marked effect on circulating vasopressin concentrations, probably as a result of complex changes since administration of either oestrogen or progesterone in doses giving normal circulating concentrations had little effect. Journal of Endocrinology (1990) 124, 277–284

Factors associated with vasopressin release in exercising swine

1994 ◽  
Vol 266 (1) ◽  
pp. R118-R124 ◽  
Author(s):  
C. L. Stebbins ◽  
J. D. Symons ◽  
M. D. McKirnan ◽  
F. F. Hwang
Keyword(s):  
Plasma Volume ◽  
Plasma Concentrations ◽  
Plasma Osmolality ◽  
Plasma Renin ◽  
Treadmill Running ◽  
Maximal Heart Rate ◽  
Ang Ii ◽  
Strong Correlations ◽  
Vasopressin Release ◽  
Lysine Vasopressin

This study examined the effect of dynamic exercise on vasopressin release in the miniswine and factors that may elicit this response (n = 15). Thus lysine vasopressin (LVP), the catecholamines epinephrine and norepinephrine (EPI and NE), plasma renin activity (PRA), and plasma volume, Na+, and osmolality were measured before and during treadmill running at work intensities of 60, 80, and 100% of each swine's maximal heart rate reserve (HRR). LVP increased in a progressive manner similar to that of humans, ranging from 5.9 +/- 0.4 pg/ml before exercise to 30.1 +/- 4.5 pg/ml during maximal exercise. EPI, NE, and PRA [an index of angiotensin II (ANG II) activity] demonstrated a pattern of response comparable to LVP. Although these hormones can influence the release of LVP, only PRA displayed a strong correlation with LVP (r = 0.84). When ANG II synthesis was blocked (captopril, 1-3 mg/kg, intra-atrial injection) during exercise (80% HRR), plasma LVP was reduced from 9.9 +/- 0.6 to 7.5 +/- 0.6 pg/ml (P < 0.05). In addition, moderate-to-strong correlations were found between plasma concentrations of LVP and plasma osmolality (r = 0.79) and body temperature (r = 0.78). Plasma LVP also correlated with decreases in plasma volume (r = 0.84). These data suggest that the miniswine model is a good one for studying vasopressin effects during exercise and that ANG II appears to be a particularly strong stimulus for the release of this hormone.

Osmoregulation of thirst and vasopressin during normal menstrual cycle

1988 ◽  
Vol 254 (4) ◽  
pp. R641-R647 ◽  
Author(s):  
T. J. Vokes ◽  
N. M. Weiss ◽  
J. Schreiber ◽  
M. B. Gaskill ◽  
G. L. Robertson
Keyword(s):  
Menstrual Cycle ◽  
Luteal Phase ◽  
Plasma Osmolality ◽  
Free Water ◽  
Urine Osmolality ◽  
Free Water Clearance ◽  
Vasopressin Release ◽  
Plasma Vasopressin ◽  
Normal Menstrual Cycle ◽  
Basal Plasma

Changes in osmoregulation during normal menstrual cycle were examined in 15 healthy women. In 10 women, studied repetitively during two consecutive menstrual cycles, basal plasma osmolality, sodium, and urea decreased by 4 mosmol/kg, 2 meq/l, and 0.5 mM, respectively (all P less than 0.02) from the follicular to luteal phase. Plasma vasopressin, protein, hematocrit, mean arterial pressure, and body weight did not change. In five other women, diluting capacity and osmotic control of thirst and vasopressin release were assessed in follicular, ovulatory, and luteal phases. Responses of thirst and/or plasma vasopressin, urine osmolality, osmolal and free water clearance to water loading, and infusion of hypertonic saline were normal and similar in the three phases. However, the plasma osmolality at which plasma vasopressin and urine osmolality were maximally suppressed as well as calculated osmotic thresholds for thirst and vasopressin release were lower by 5 mosmol/kg in the luteal than in the follicular phase. This lowering of osmotic thresholds for thirst and vasopressin release, which occurs in the luteal phase, is qualitatively similar to that observed in pregnancy and should be taken into account when studying water balance and regulation of vasopressin secretion in healthy cycling women.

Increased plasma osmolality stimulates peripheral and central vasopressin release in male and female rats

1994 ◽  
Vol 267 (4) ◽  
pp. R923-R928 ◽  
Author(s):  
M. Ota ◽  
J. T. Crofton ◽  
H. Liu ◽  
G. Festavan ◽  
L. Share
Keyword(s):  
Interstitial Fluid ◽  
Plasma Osmolality ◽  
Female Rats ◽  
Microdialysis Probe ◽  
Vasopressin Release ◽  
Arterial Blood ◽  
Plasma Vasopressin ◽  
Male And Female Rats ◽  
Supraoptic Nuclei

It has been demonstrated that the neurohypophysial hormones can be released intrahypothalamically by the paraventricular (PVN) and supraoptic nuclei. The present experiments were undertaken to determine whether a physiological stimulus for vasopressin release, increased plasma osmolality, will stimulate the release of vasopressin by the PVN into the surrounding interstitial fluid, and whether the responses are affected by gender. Intravenous infusion of 2.5 M NaCl for 60 min (0.1 ml.kg-1.min-1) in conscious rats resulted in an increased vasopressin concentration in the dialysate from a microdialysis probe adjacent to the PVN. This response was greater in nonestrous females than in males. On the other hand, the rise in the plasma vasopressin concentration was greater in males than in nonestrous females. Mean arterial blood pressure increased and heart rate decreased, but these responses were not affected by gender. The role of centrally released vasopressin in the control of the peripheral release of vasopressin is conjectural, but both responses may be modulated by the gonadal steroid hormones.

Hypothalamic thermal stimulation modulates vasopressin release in hyperosmotically stimulated rabbits

1994 ◽  
Vol 267 (4) ◽  
pp. R1089-R1097 ◽  
Author(s):  
R. Keil ◽  
R. Gerstberger ◽  
E. Simon
Keyword(s):  
Isotonic Saline ◽  
Plasma Osmolality ◽  
Significant Rise ◽  
Hypertonic Solution ◽  
Temperature Plasma ◽  
Evaporative Water ◽  
Vasopressin Release ◽  
Plasma Vasopressin ◽  
Hypothalamic Control ◽  
Hypertonic Stimulation

Under thermoneutral conditions conscious rabbits received systemic infusions of NaCl as hypertonic solution (90 mueq.min-1.kg body wt-1), which raised their plasma osmolality from 283 to 312 mosmol/kgH2O. Rabbits receiving isotonic saline served as controls. Hypertonic stimulation induced a 60% reduction of both respiratory frequency and evaporative water loss. Rectal temperature rose by 0.4 degrees C despite enhanced peripheral vasodilation as indicated by increased ear skin temperature. Plasma vasopressin (AVP), aldosterone (ALDO), and corticosterone (COR) were significantly elevated from 6 to 16 pg/ml, 90 to 180 pg/ml, and 17 to 40 ng/ml, respectively. To elucidate the importance of central temperature for AVP and adrenal corticosteroid release, hypothalamic thermal stimulations (20 min) were superimposed during established iso- and hyperosmotic steady-state conditions. Different from isosmotic controls, hyperosmotic animals responded to hypothalamic cooling (37 degrees C) with a significant decrease in plasma AVP from 16 to 13 pg/ml and to hypothalamic warming (41 degrees C) with a significant rise from 16 to 19 pg/ml. A weak temperature effect on COR release was also disclosed, especially of hypothalamic cooling, which significantly lowered plasma COR from 42 to 34 ng/ml. These results provide evidence for positive local temperature coefficients of hypothalamic control of AVP release and suggest a similar property also for the control of COR release by the hypothalamo-adenohypophysial axis.

OESTROGEN RECEPTORS IN RAT MAMMARY TISSUE AND PLASMA CONCENTRATIONS OF PROLACTIN DURING MAMMARY CARCINOGENESIS INDUCED BY OESTROGEN AND IONIZING RADIATION

1981 ◽  
Vol 88 (2) ◽  
pp. 233-241 ◽  
Author(s):  
M. A. BLANKENSTEIN ◽  
E. MULDER ◽  
J. J. BROERSE ◽  
H. J. VAN DER MOLEN
Keyword(s):  
Ionizing Radiation ◽  
Oestrogen Receptor ◽  
Plasma Concentrations ◽  
Mammary Tissue ◽  
Control Group ◽  
Plasma Prolactin ◽  
X Rays ◽  
Oestrogen Receptors ◽  
Sprague Dawley ◽  
Oestrogen Treatment

Female Sprague–Dawley rats received a subcutaneous implant containing 2 mg oestradiol at the age of 7 weeks. One week later half of the rats treated with oestrogen and half of the rats in an untreated control group were irradiated with 2 Gy (200 rad) of X-rays. The content of oestrogen receptor of the mammary tissue and the concentration of prolactin in the plasma were studied at intervals of 2 months for a period of 14 months after this treatment. Oestrogen treatment resulted in a decrease in the content of oestrogen receptors in the mammary tissue of both irradiated and non-irradiated rats. In oestrogen-treated rats, plasma prolactin was raised 10–50 times and pituitary tumours were observed. Radiation had no additional effect on the oestrogen-receptor content of mammary tissue or the concentration of plasma prolactin. The changes in the oestrogen-receptor content of mammary tissue and the prolactin concentration of plasma preceded the development of mammary tumours. It is suggested that the synergistic action of oestrogen and radiation on rat mammary tumour development is the result of a stimulation by oestrogen and/or prolactin of the sensitivity of the mammary gland to ionizing radiation.

Neuroendocrine factors mediating polydipsia induced by dietary Na, Cl, and K depletion

1986 ◽  
Vol 251 (6) ◽  
pp. R1071-R1077 ◽  
Author(s):  
A. Saikaley ◽  
D. Bichet ◽  
J. Kucharczyk ◽  
L. N. Peterson
Keyword(s):  
Water Intake ◽  
Time Course ◽  
Plasma Concentrations ◽  
Urine Volume ◽  
Plasma Osmolality ◽  
Male Rats ◽  
Angiotensin Receptors ◽  
Salt Diet ◽  
Low Salt ◽  
Electrolytic Lesions

We investigated whether the increased intake of water during dietary electrolyte depletion is related to activation of the renin-angiotensin system. Young adult male rats were fed a low Na-, Cl-, K-free (low-salt) diet for 2 wk during which measurements were made of daily water intake and urine volume, plasma osmolality (Posm) and electrolytes, and plasma renin activity (PRA) and angiotensin I (ANG I) concentration. Water intake and urine output increased on day 3 of the low-salt diet, reached a maximum on day 4, and remained elevated, paralleling the time course of increases in PRA and ANG I plasma concentrations. Posm was normal after 2 days on the low-salt, although it was significantly lower by day 11. Renal concentrating ability was not different from controls after 6 days, but was significantly reduced after 11 days of treatment. Electrolytic lesions of the subfornical organ (SFO) abolished the low-salt diet-induced polydipsia, but had no effect on the diet-induced increases in PRA and plasma ANG I concentration. These data demonstrate that polydipsia induced by feeding a low-salt diet can develop in the presence of a normal or reduced Posm and precedes the development of a renal concentrating defect. The primary polydipsia is associated with elevated PRA and ANG I and appears to be mediated by angiotensin receptors in the SFO.

Osmotic thirst and vasopressin release in humans: a double-blind crossover study

1985 ◽  
Vol 248 (6) ◽  
pp. R645-R650 ◽  
Author(s):  
P. A. Phillips ◽  
B. J. Rolls ◽  
J. G. Ledingham ◽  
M. L. Forsling ◽  
J. J. Morton
Keyword(s):  
Hypertonic Saline ◽  
Water Intake ◽  
Sodium Concentration ◽  
Plasma Sodium ◽  
Double Blind ◽  
Vasopressin Release ◽  
Arterial Blood ◽  
Plasma Vasopressin ◽  
Plasma Sodium Concentration ◽  
Osmotic Thirst

Thirst is a subjective sensation. Therefore to investigate further the nature, intensity, and specificity of osmotic thirst, we studied the effects of double-blind infusions of hypertonic (0.45 M) and isotonic (0.15 M) saline on subjective ratings and sensations of thirst, water intake, plasma vasopressin, and body fluids in seven healthy volunteer young men. Only the hypertonic saline significantly increased plasma sodium concentration, plasma osmolality, plasma vasopressin concentration, and visual analog ratings of thirst sensations. Both infusions expanded blood volume, which was greater with the hypertonic saline infusion. Neither solution significantly altered mean arterial blood pressure nor plasma angiotensin levels. Throughout a 60-min drinking period after the infusions, water intake was always significantly greater after the hypertonic saline than after the isotonic saline. The subjects described the thirst sensations as mainly due to a dry unpleasant tasting mouth, which was promptly relieved by drinking. Visual analog rating changes confirmed the subjective reports. Finally, the effects on thirst and vasopressin secretion were observed at plasma sodium concentration and osmolality changes that are well within the physiological range.

The influence of reproductive status on vasopressin release in the rat

1991 ◽  
Vol 130 (3) ◽  
pp. 387-393 ◽  
Author(s):  
M. L. Forsling ◽  
H. Kelestimur ◽  
R. Windle
Keyword(s):  
Polyethylene Glycol ◽  
Fluid Balance ◽  
Ovarian Function ◽  
Extracellular Fluid ◽  
Hormone Release ◽  
Vasopressin Release ◽  
Ovarian Steroids ◽  
Plasma Vasopressin ◽  
Long Acting ◽  
Lh Releasing Hormone

ABSTRACT It has been shown that surgical ovariectomy of the rat results in a fall in plasma vasopressin concentrations suggesting that ovarian steroids may influence hormone release. To determine whether a similar fall is found on suppression of the oestrous cycle, vasopressin concentrations were monitored after treatment with the antioestrogen preparation tamoxifen or a long-acting analogue of LH-releasing hormone (LHRH) which suppresses ovarian function. Treatment with either agent was found to result in a fall in circulating vasopressin concentrations, with little effect on fluid balance. To determine whether the ovary could influence the vasopressin release in response to known stimuli, hormone concentrations were measured in ovariectomized animals during extracellular fluid hypertonicity produced by an i.p. injection of hypertonic saline and hypovolaemia produced by an i.p. injection of polyethylene glycol. It was found that after ovariectomy or treatment with tamoxifen, the response to hypertonicity was unaffected but that to hypovolaemia was attenuated. Treatment with LHRH affected the response to both hypovolaemia and hypertonicity. Journal of Endocrinology (1991) 130, 387–393

Inhibitory mechanism of the nucleus of the solitary tract involved in the control of cardiovascular, dipsogenic, hormonal, and renal responses to hyperosmolality

2013 ◽  
Vol 304 (7) ◽  
pp. R531-R542 ◽  
Author(s):  
Graziela T. Blanch ◽  
André H. Freiria-Oliveira ◽  
David Murphy ◽  
Renata F. Paulin ◽  
José Antunes-Rodrigues ◽  
...  
Keyword(s):  
Water Intake ◽  
Pressor Response ◽  
Plasma Osmolality ◽  
Visceral Afferents ◽  
Solitary Tract ◽  
Plasma Vasopressin ◽  
Inhibitory Mechanisms ◽  
Acute Increase ◽  
Renal Responses ◽  
Vasopressinergic Neurons

The nucleus of the solitary tract (NTS) is the primary site of visceral afferents to the central nervous system. In the present study, we investigated the effects of lesions in the commissural portion of the NTS (commNTS) on the activity of vasopressinergic neurons in the hypothalamic paraventricular (PVN) and supraoptic (SON) nuclei, plasma vasopressin, arterial pressure, water intake, and sodium excretion in rats with plasma hyperosmolality produced by intragastric 2 M NaCl (2 ml/rat). Male Holtzman rats with 15–20 days of sham or electrolytic lesion (1 mA; 10 s) of the commNTS were used. CommNTS lesions enhanced a 2 M NaCl intragastrically induced increase in the number of vasopressinergic neurons expressing c-Fos in the PVN (28 ± 1, vs. sham: 22 ± 2 c-Fos/AVP cells) and SON (26 ± 4, vs. sham: 11 ± 1 c-Fos/AVP cells), plasma vasopressin levels (21 ± 8, vs. sham: 6.6 ± 1.3 pg/ml), pressor responses (25 ± 7 mmHg, vs. sham: 7 ± 2 mmHg), water intake (17.5 ± 0.8, vs. sham: 11.2 ± 1.8 ml/2 h), and natriuresis (4.9 ± 0.8, vs. sham: 1.4 ± 0.3 meq/1 h). The pretreatment with vasopressin antagonist abolished the pressor response to intragastric 2 M NaCl in commNTS-lesioned rats (8 ± 2.4 mmHg at 10 min), suggesting that this response is dependent on vasopressin secretion. The results suggest that inhibitory mechanisms dependent on commNTS act to limit or counterbalance behavioral, hormonal, cardiovascular, and renal responses to an acute increase in plasma osmolality.

scholarly journals Influence of oral buprenorphine, oral naltrexone or morphine on the effects of laparotomy in the rat

1998 ◽  
Vol 32 (2) ◽  
pp. 149-161 ◽  
Author(s):  
J. H. Liles ◽  
P. A. Flecknell ◽  
J. Roughan ◽  
I. Cruz-Madorran
Keyword(s):  
Body Weight ◽  
Water Intake ◽  
Water Consumption ◽  
Subcutaneous Administration ◽  
Endogenous Opioids ◽  
Control Group ◽  
Opioid Agonist ◽  
Beneficial Effects ◽  
Oral Naltrexone ◽  
Food And Water Intake

The effects of oral administration of buprenorphine ('buprenorphine jello'), a partial μ opioid agonist, oral naltrexone, a μ antagonist and morphine, a μ agonist, were investigated in rats following laparotomy. Food and water consumption and body weight were reduced in rats that underwent surgery. Rats undergoing anaesthesia alone showed only a small reduction in water consumption. Administration of oral buprenorphine (0.5 mg/kg in flavoured gelatin) decreased the effects of surgery on body weight and water intake when compared to untreated (vehicle alone) controls. The magnitude of this beneficial effect was similar to that seen in previous studies using subcutaneous administration of buprenorphine. The fall in body weight and food and water intake following surgery was similar in the groups which received morphine and the control group which received vehicle (jelly). Neither the magnitude of the fall in body weight, and food and water intake, nor the behavioural scores differed between naltrexone and control (vehicle alone) rats following surgery. This suggests that the beneficial effects of partial agonist analgesics are mediated by a reduction in pain rather than by antagonism of endogenous opioids. Both anaesthesia and surgery caused changes in behaviour, but the major effects of buprenorphine in normal (unoperated) rats severely limited the value of behavioural parameters as a means of assessing possible beneficial effects of analgesic administration.

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