Localization of central nervous system structures mediating extracellular thirst in the female rat

1984 ◽  
Vol 100 (2) ◽  
pp. 183-NP ◽  
Author(s):  
J. Kucharczyk
Keyword(s):  
Angiotensin Ii ◽  
Water Intake ◽  
Extracellular Fluid ◽  
Oestrous Cycle ◽  
Female Rats ◽  
Female Rat ◽  
Adrenergic Agonist ◽  
Preoptic Region ◽  
Body Fluid Compartments ◽  
Fluid Compartments

ABSTRACT Water intake elicited by microinjection of the hormone angiotensin-II into the preoptic region of cyclic female rats was significantly less on days of vaginal oestrus than at dioestrus or metoestrus, whereas the drinking of 2·7% NaCl solution, to which rats also had access, did not vary with the cycle. Administration of the same dose of angiotensin-II to the subfornical organ and the lateral cerebral ventricles induced drinking at all stages of the oestrous cycle, but the volumes of water or 2·7% NaCl ingested did not vary with the cycle. Water intake after subcutaneous injection of isoprenaline, a β-adrenergic agonist which causes increased angiotensin biosynthesis, varied cyclically with the stage of the oestrous cycle. On the other hand, water and 2·7% NaCl intakes induced by intraperitoneal injection of hypertonic NaCl (a cellular stimulus of thirst) or by 24-h water deprivation (which dehydrates both the extracellular and cellular body fluid compartments) did not differ significantly at the various stages of the oestrous cycle. The finding that fluctuations in angiotensin- and isoprenaline-induced water intake parallel the changes in spontaneous 24-h drinking suggests that the preoptic region may play an important role in the maintenance of extracellular fluid balance in synchrony with the oestrous cycle. J. Endocr. (1984) 100, 183–188

Ovarian steroid regulation of angiotensin II-induced water intake in the rat

1999 ◽  
Vol 276 (1) ◽  
pp. R90-R96 ◽  
Author(s):  
Lori R. Kisley ◽  
Randall R. Sakai ◽  
Li Yun Ma ◽  
Steven J. Fluharty
Keyword(s):  
Water Intake ◽  
Peptide Hormone ◽  
Estradiol Benzoate ◽  
Female Rats ◽  
Female Rat ◽  
Ang Ii ◽  
Concurrent Administration ◽  
Ovarian Steroid ◽  
Steroid Administration ◽  
Dose Dependent

Spontaneous water intake as well as thirst elicited by ANG II has been shown to be influenced by the stage of the estrous cycle in the female rat. In these experiments, the contribution of each of the ovarian steroid hormones to the regulation of water intake was examined. Ovariectomized female rats were given replacement doses of estrogen, progesterone, or both, and their responsiveness to an intracerebroventricular injection of ANG II was tested. Forty-eight-hour treatment with estradiol benzoate attenuated ANG II-induced thirst by as much as 70% compared with control animals. The effect of estrogen on drinking was dose dependent and could be completely blocked with concurrent administration of the antiestrogen CI-628. In contrast, progesterone, given alone or after estrogen, did not significantly affect ANG II-induced water intake when animals were tested at 4 or 24 h after steroid administration. A central interaction between the peptide hormone ANG II and estrogen, involving a genomic mechanism, may underlie the cyclicity in water intake behavior observed in the rat.

Regulation of body fluid compartments during short-term spaceflight

1996 ◽  
Vol 81 (1) ◽  
pp. 105-116 ◽  
Author(s):  
C. S. Leach ◽  
C. P. Alfrey ◽  
W. N. Suki ◽  
J. I. Leonard ◽  
P. C. Rambaut ◽  
...  
Keyword(s):  
Body Fluid ◽  
Extracellular Fluid ◽  
Plasma Renin ◽  
Capillary Membranes ◽  
Urinary Cortisol Excretion ◽  
Hormone Responses ◽  
Body Fluid Compartments ◽  
Cortisol Excretion ◽  
Fluid Compartments ◽  
Total Body

The fluid and electrolyte regulation experiment with seven subjects was designed to describe body fluid, renal, and fluid regulatory hormone responses during the Spacelab Life Sciences-1 (9 days) and -2 (14 days) missions. Total body water did not change significantly. Plasma volume (PV; P < 0.05) and extracellular fluid volume (ECFV; P < 0.10) decreased 21 h after launch, remaining below preflight levels until after landing. Fluid intake decreased during weightlessness, and glomerular filtration rate (GFR) increased in the first 2 days and on day 8 (P < 0.05). Urinary antidiuretic hormone (ADH) excretion increased (P < 0.05) and fluid excretion decreased early in flight (P < 0.10). Plasma renin activity (PRA; P < 0.10) and aldosterone (P < 0.05) decreased in the first few hours after launch; PRA increased 1 wk later (P < 0.05). During flight, plasma atrial natriuretic peptide concentrations were consistently lower than preflight means, and urinary cortisol excretion was usually greater than preflight levels. Acceleration at launch and landing probably caused increases in ADH and cortisol excretion, and a shift of fluid from the extracellular to the intracellular compartment would account for reductions in ECFV. Increased permeability of capillary membranes may be the most important mechanism causing spaceflight-induced PV reduction, which is probably maintained by increased GFR and other mechanisms. If the Gauer-Henry reflex operates during spaceflight, it must be completed within the first 21 h of flight and be succeeded by establishment of a reduced PV set point.

Shift in body fluid compartments after dehydration in humans

1988 ◽  
Vol 65 (1) ◽  
pp. 318-324 ◽  
Author(s):  
H. Nose ◽  
G. W. Mack ◽  
X. R. Shi ◽  
E. R. Nadel
Keyword(s):  
Body Fluid ◽  
Extracellular Fluid ◽  
Plasma Osmolality ◽  
Free Water ◽  
Inverse Correlation ◽  
The Body ◽  
Free Water Clearance ◽  
Before And After ◽  
Body Fluid Compartments ◽  
Fluid Compartments

To investigate the influence of [Na+] in sweat on the distribution of body water during dehydration, we studied 10 volunteer subjects who exercised (40% of maximal aerobic power) in the heat [36 degrees C, less than 30% relative humidity (rh)] for 90-110 min to produce a dehydration of 2.3% body wt (delta TW). After dehydration, the subjects rested for 1 h in a thermoneutral environment (28 degrees C, less than 30% rh), after which time the changes in the body fluid compartments were assessed. We measured plasma volume, plasma osmolality, and [Na+], [K+], and [Cl-] in plasma, together with sweat and urine volumes and their ionic concentrations before and after dehydration. The change in the extracellular fluid space (delta ECF) was estimated from chloride distribution and the change in the intracellular fluid space (delta ICF) was calculated by subtracting delta ECF from delta TW. The decrease in the ICF space was correlated with the increase in plasma osmolality (r = -0.74, P less than 0.02). The increase in plasma osmolality was a function of the loss of free water (delta FW), estimated from the equation delta FW = delta TW - (loss of osmotically active substance in sweat and urine)/(control plasma osmolality) (r = -0.79, P less than 0.01). Free water loss, which is analogous to "free water clearance" in renal function, showed a strongly inverse correlation with [Na+] in sweat (r = -0.97, P less than 0.001). Fluid movement out of the ICF space attenuated the decrease in the ECF space.(ABSTRACT TRUNCATED AT 250 WORDS)

Role of the subcommissural organ in the control of gonadotrophin secretion in the female rat

1982 ◽  
Vol 95 (2) ◽  
pp. 207-213 ◽  
Author(s):  
Patrizia Limonta ◽  
Roberto Maggi ◽  
Luciano Martini ◽  
Flavio Piva
Keyword(s):  
Subcommissural Organ ◽  
Oestrous Cycle ◽  
Female Rats ◽  
Ovariectomized Rats ◽  
Normal Female ◽  
Female Rat ◽  
Thermal Lesions ◽  
Gonadotrophin Secretion

Thermal lesions were placed in the subcommissural organ (SCO) of female rats with normal cycles and long-term ovariectomized rats. In normal female rats SCO lesions disrupted the oestrous cycle in more than half of the animals, the majority of which entered a state of prolonged dioestrus. In these animals, serum gonadotrophin levels were similar to those of rats with regular cycles on day 2 of dioestrus. In animals in which the oestrous cycle was maintained, a delayed LH surge occurred on the day of pro-oestrus and the pro-oestrous FSH surge was absent. The usual increase in FSH on the day of oestrus was present. Lesions in the SCO did not change the high gonadotrophin levels typical of ovariectomized animals. These results suggested that the SCO may play a role in the control of the cyclic but not the tonic release of the gonadotrophins. In particular, it appears that the SCO might be involved in the regulation of the hypersecretion of FSH during the day of pro-oestrus.

Water intake elicited by injections of angiotensin II into preoptic area of rats

1981 ◽  
Vol 240 (1) ◽  
pp. R70-R74 ◽  
Author(s):  
D. B. Richardson ◽  
G. J. Mogenson
Keyword(s):  
Angiotensin Ii ◽  
Water Intake ◽  
Preoptic Area ◽  
High Dose ◽  
Preoptic Nucleus ◽  
Cerebral Ventricles ◽  
Preoptic Region ◽  
Medial Preoptic Nucleus ◽  
Autoradiographic Analysis

Drinking in response to unilateral injections of angiotensin II (AII) into the preoptic area is relatively weak and a relatively high dose of AII is required. A comparison was made of the drinking elicited by bilateral and unilateral injections of AII. Reliable drinking was observed when 5 X 10(-12) mol of AII in 0.2 microliter was injected bilaterally into the preoptic area, and in some animals when the dose of AII was 0.5 X 10(-12) mol in 0.2 microliter. The volumes of water intake were significantly larger with bilateral injections compared to unilateral injections. By injection of tritiated AII to elicit drinking and subsequent autoradiographic analysis of brain sections, it was shown that the injections were confined to the preoptic region and did not reach the cerebral ventricles. The results suggest that 1) bilateral injections may be more appropriate for comparing the preoptic region with other putative angiotensin receptive sites, 2) there is a greater responsiveness of the preoptic region to bilateral as compared with unilateral injections, and 3) the AII receptive area is diffusely represented in the region of the medial preoptic nucleus.

Body Fluid Compartments

1977 ◽  
Vol 5 (4) ◽  
pp. 284-294 ◽  
Author(s):  
Roy W. Pain
Keyword(s):  
Body Fluid ◽  
Extracellular Fluid ◽  
Sodium Potassium ◽  
Membrane Pump ◽  
Interstitial Fluid Volume ◽  
New Concepts ◽  
Body Fluid Compartments ◽  
Fluid Compartments ◽  
Total Body ◽  
Osmolar Gap

The terms mole, molality, molarity, osmole, osmolality, osmolarity, osmolar gap and anion gap are defined and their clinical usefulness indicated. The following body fluid compartments are described: total body water ( TBW), extracellular fluid ( ECF), intracellular fluid ( ICF), transcellular fluid ( TCF), plasma volume, red cell volume and interstitial fluid volume. Isotope-dilution techniques are briefly discussed and representative normal values for the various compartments according to sex and age are indicated. The physiological mechanisms that maintain the distinctive ionic compositions of the various fluid spaces are briefly outlined. New concepts of the function of the gel matrix and of the lymph drainage of the interstitium are presented. Opposing models to the sodium-potassium membrane pump are briefly described.

Body fluid volumes in rats with mestranol-induced hypertension

1986 ◽  
Vol 251 (1) ◽  
pp. H190-H195 ◽  
Author(s):  
W. L. Fowler ◽  
J. A. Johnson ◽  
K. D. Kurz ◽  
D. W. Zeigler ◽  
D. E. Dostal ◽  
...  
Keyword(s):  
Body Weight ◽  
Oral Contraceptive ◽  
Lean Body Mass ◽  
Body Mass ◽  
Body Fluid ◽  
Tritiated Water ◽  
Extracellular Fluid ◽  
Fluid Volume ◽  
Female Rats ◽  
Fluid Compartments

Because estrogens have been reported to produce sodium retention, this study investigated the possibility that hypertension in rats resulting from the ingestion of an estrogen used as an oral contraceptive could be due to increases in body fluid volumes. Female rats were given feed containing mestranol for 1, 3, and 6 mo; control rats were given the feed without mestranol. The mestranol-treated rats had higher arterial pressures than the controls only after 6 mo of treatment. Plasma volume, extracellular fluid volume, and total body water were measured in each rat by the distribution volumes of radioiodinated serum albumin, 35SO4, and tritiated water, respectively. Values for blood volume, interstitial fluid volume, and intracellular fluid volume were derived from these measurements. These body fluid volumes, expressed per 100 g of body weight, were not different between the mestranol-treated rats and their controls at any of the three treatment times. Due to differences in body weight and lean body mass between the mestranol-treated and the control rats, these volumes also were expressed per 100 g of lean body mass. Again, no differences were observed between the mestranol-treated rats and the control rats for any of these body fluid compartments at any of the treatment times. These studies, therefore, were unable to provide evidence that increases in body fluid volumes contributed to the elevated arterial pressure in this rat model of oral contraceptive hypertension.

Roles of catecholamine at the preoptic region in the regulation of cyclic ovulation and gonadotropin

1987 ◽  
Vol 116 (3) ◽  
pp. 357-363 ◽  
Author(s):  
Ryuhei Hashimoto ◽  
Fukuko Kimura
Keyword(s):  
Third Ventricle ◽  
Oestrous Cycle ◽  
Ovariectomized Rats ◽  
Blood Levels ◽  
Female Rat ◽  
Preoptic Region ◽  
Gonadotropin Secretion ◽  
The Third ◽  
Lh Secretion ◽  
Intact Rats

Abstract. Experiments were designed to see how a transplantation of newborn norepinephrine (NE) neurons from A-6 groups or dopamine (DA) neurons from A-10 groups in the third ventricle at the level of the preoptic region affected the vaginal oestrous cycle and gonadotropin secretion in the female rat. Sixty-two rats that had tissues in contact with the preoptic region were evaluated as having surviving transplants by histological examination after sacrifice. The rats that had surviving NE-neuron transplants frequently showed prolongation of oestrus during the 70-day study period, indicating that ovulation was severely impaired in these rats. However, after ovariectomy, they showed a pulsatile secretion of LH with a remarkably large amplitude. The DA-neuron transplants sustained the oestrous cycle unchanged, but increased blood levels of FSH prior to the ovulatory secretion of gonadotropin. Pulsatile LH secretion was not affected. Sham and cerebellum control rats did not show any significant changes in the oestrous cycle. The results suggest that the NEneuron transplants at the preoptic region somehow inhibit gonadotropin secretion in intact rats, whereas they facilitate it in ovariectomized rats. The DA-neuron transplants appear to exert facilitatory effects on FSH secretion in intact rats.

CHANGES IN HYPOTHALAMIC PEPTIDASE ACTIVITY DURING THE OESTROUS CYCLE IN THE ADULT FEMALE RAT

1973 ◽  
Vol 74 (1) ◽  
pp. 41-48 ◽  
Author(s):  
E. C. Griffiths ◽  
K. C. Hooper
Keyword(s):  
Enzyme Activity ◽  
Luteinizing Hormone ◽  
Oestrous Cycle ◽  
Female Rats ◽  
Male Rats ◽  
Supernatant Fraction ◽  
Normal Male ◽  
Normal Female ◽  
Peptidase Activity ◽  
Female Rat

ABSTRACT The activity of peptidases in the rat hypothalamus which are capable of inactivating oxytocin has previously been found to vary with stimuli known to influence gonadotrophin release and may be related to both luteinizing hormone (LH) and luteinizing hormone releasing factor (LH-RF) release (Griffith & Hooper 1972a,b). In the present study, enzyme activity was determined in normal female rats during the morning and afternoon of each stage of the oestrous cycle, in normal rats, and in female rats injected neonatally with testosterone. The activity of the supernatant fraction was found to be not significantly different during the morning of each stage, but was greatly decreased on the afternoon of pro-oestrus; particulate activity did not vary during the oestrous cycle. Supernatant and particulate activities were found to be the same in normal male rats and testosterone-treated females, as previously shown. Both fractions' activities were significantly less than those found in the oestrous cycle, other than on the afternoon of pro-oestrus. These results indicate changes in hypothalamic peptidase activity during the oestrous cycle which may be inversely related to LH and LH-RF release; they also confirm the masculinizing effect of neonatal testosterone on the hypothalamus.

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