Pituitary and plasma vasopressin concentrations and fluid balance throughout the oestrous cycle of the rat

Ml, Forsling; Peysner, K

doi:10.1677/joe.0.1170397

Cited by 73 publications

(56 citation statements)

References 24 publications

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“…Food and water intake decrease during pro-estrous and estrous. Also, urinary output and urinary sodium excretion are decreased in estrous compared to diestrus (Forsling & Peysner 1988). It is known that physiological concentrations of estrogen stimulate the release of OT by the dendrites of magnocellular neurones in the SON (Wang et al 1995), and studies in our laboratory have shown that the secretion of OT varies during the estrous cycle, increasing during pro-estrous and the morning of estrous (Caligioni & Franci 2002).…”

Section: Discussionmentioning

confidence: 80%

Effect of the interaction between food state and the action of estrogen on oxytocinergic system activity

Lucio-Oliveira¹,

Franci²

2011

Journal of Endocrinology

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Increased plasma osmolality by food intake evokes augmentation of plasma oxytocin (OT). Ovarian steroids may also influence the balance of body fluids by acting on OT neurones. Our aim was to determine if estrogen influences the activity of OT neurones in paraventricular nucleus (PVN) and supraoptic nucleus (SON) under different osmotic situations. Ovariectomized rats (OVX) were treated with either estradiol (E 2 ) or vehicle and were divided into three groups: group I was fed ad libitum, group II underwent 48 h of fasting, and group III was refed after 48 h of fasting. On the day of the experiment, blood samples were collected to determine the plasma osmolality and OT. The animals were subsequently perfused, and OT/FOS immunofluorescence analysis was conducted on neurones in the PVN and the SON. When compared to animals which were fasted or fed ad libitum, the plasma osmolality of refed animals was higher, regardless of whether they were treated with vehicle or E 2 . We observed neural activation of OT cells in vehicle-or E 2 -treated OVX rats refed after 48 h of fasting, but not in animals fed ad libitum or in animals that only underwent 48 h of fasting. Finally, the percentage of neurones that co-expressed OT and FOS was lower in both the PVN and the SON of animals treated with E 2 and refed, when compared to vehicle-treated animals. These results suggest that E 2 may have an inhibitory effect on OT neurones and may modulate the secretion of OT in response to the increase of osmolality induced by refeeding.

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Section: Discussionmentioning

confidence: 80%

Effect of the interaction between food state and the action of estrogen on oxytocinergic system activity

Lucio-Oliveira¹,

Franci²

2011

Journal of Endocrinology

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“…Inter-and intra-assay coefficients of variation were 8.1% (n = 20) and 8.3% (n = 20), respectively. AVP was extracted as described elsewhere [13] using the DSL-1800 Arginine Vasopressin Radioimmunoassay kit from Diagnostic Systems Laboratories, Webster, Texas, USA. Vasopressin was extracted from plasma using Sep Pak C18 cartridges (Millipore Water Associates, Harrow, Middlesex, UK).…”

Section: Plasma Avp and Aldosterone Measurementsmentioning

confidence: 99%

Renal Function in Male Sprague-Dawley Rats Concurrently Exposed to Long-Term Nicotine (3-{1-Methyl-2-Pyrrolidinyl}Pyridine) and Methylated Spirits (Methyl Alcohol)

2008

Renal Failure

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Abuse of nicotine and methylated spirits is a global problem. The current study determined the concurrent influence of nicotine and methylated spirits on renal hemodynamics. Two series of experimental protocols were designed: conscious and anesthetized vehicle loading. Conscious animals received nicotine (0.1 mg.kg -1 bwt, 0.26-0.30 mL), methylated spirits (1.0 g.kg -1 bwt, 0.26-0.30 mL), combined nicotine and methylated spirits, and control animals (water, 0.26-0.30 mL). Anesthetized animals were challenged with a continuous jugular infusion of 0.077M NaCl. Plasma nicotine concentration was significantly elevated in combined conscious treatments by comparison with animals infused nicotine alone. Plasma arginine vasopressin was significantly attenuated in combined conscious groups, and those infused methylated spirits alone. Aldosterone was elevated in all conscious groups. Both plasma ethanol and methanol concentrations were elevated in rats concurrently administered nicotine and methylated spirits compared with those given methylated spirits alone. Urinary Na + levels were significantly elevated in all anesthetized groups associated with attenuated aldosterone concentrations. Plasma nicotine concentrations were increased in combined treatments. Plasma ethanol levels were significantly reduced and elevated in rats concurrently exposed to nicotine and methylated spirits, respectively. The present study suggests that chronic exposure to methylated spirits alone and in combination with nicotine increases urinary Na + loss. The renal toxicity is manifested hypothetically via elevations in plasma nicotine and methanol concentrations. This implies that people who concurrently consume methylated spirits and smoke cigarettes have an increased risk of renal failure by being predisposed to fluid and electrolyte disturbances.

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“…The lower limit of detection for the assay was 1·6 pmol/l, with intraand inter-assay variations of 4·1% (n=10) and 9·0% (n=10) respectively for 10 pmol/l. Vasopressin was determined as described by Forsling & Peysner (1988) using the First International Standard for vasopressin (77/501). The lower limit of detection for the assay was 0·12 0·02 pmol/l, with intra-and inter-assay variations of 7·7% (n=23) and 11·9% (n=10) respectively for 2·5 pmol/l.…”

Section: Radioimmunoassay Of Oxytocin and Vasopressinmentioning

confidence: 99%

Contribution of endogenous oxytocin to sodium excretion in anaesthetized, surgically operated rats

Walter¹,

Forsling²,

Shirley³

2000

Journal of Endocrinology

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In order to determine the possible role of endogenous oxytocin in controlling electrolyte and water excretion in animals whose renal function is being assessed by invasive techniques, rats were anaesthetized and subjected to micropuncture surgery. Clearance measurements were made in the presence and absence of the potent oxyto- 9 ]-vasotocin. In rats infused with vehicle alone, glomerular filtration rate (GFR), sodium excretion and urine flow rate remained stable. In contrast, in antagonisttreated rats GFR was modestly reduced (P<0·05), and there were large falls in both absolute and fractional sodium excretion (P<0·01 in each case) and absolute and fractional water excretion (P<0·05 in each case), indicating effects on both filtered load and fractional tubular reabsorption.The antinatriuresis was not accompanied by a change in the fractional excretion of lithium, suggesting that proximal tubular function is unaffected by oxytocin receptor antagonism; nor was it accompanied by a change in the fractional excretion of potassium, suggesting that the tubular effect is located beyond the potassium secretory site, i.e. downstream of the cortical collecting tubule.We conclude that circulating plasma concentrations of oxytocin during anaesthesia and moderate surgery are sufficient to enhance GFR and reduce fractional tubular sodium and water reabsorption. This has important implications for the interpretation of invasive studies such as micropuncture.

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Pituitary and plasma vasopressin concentrations and fluid balance throughout the oestrous cycle of the rat

Cited by 73 publications

References 24 publications

Effect of the interaction between food state and the action of estrogen on oxytocinergic system activity

Effect of the interaction between food state and the action of estrogen on oxytocinergic system activity

Renal Function in Male Sprague-Dawley Rats Concurrently Exposed to Long-Term Nicotine (3-{1-Methyl-2-Pyrrolidinyl}Pyridine) and Methylated Spirits (Methyl Alcohol)

Contribution of endogenous oxytocin to sodium excretion in anaesthetized, surgically operated rats

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