Search

Chronic consumption of ethanol in adult rats and humans leads to reduced AVP-producing neurons, and prenatal ethanol (PE) exposure has been reported to cause changes in the morphology of AVP-producing cells in the suprachiasmatic nucleus of young rats. The present studies further characterize the effects of PE exposure on AVP in the young adult rat, its hypothalamic synthesis, pituitary storage, and osmotically stimulated release. Pregnant rats were fed a liquid diet with 35% of the calories from ethanol or a control liquid diet for days 7–22 of pregnancy. Water consumption and urine excretion rate were measured in the offspring at 60–68 days of age. Subsequently, the offspring were infused with 5% NaCl at 0.05 ml·kg−1·min−1 with plasma samples taken before and at three 40-min intervals during infusion for measurement of AVP and osmolality. Urine output and water intake were ∼20% greater in PE-exposed rats than in rats with no PE exposure, and female rats had a greater water intake than males. The relationship between plasma osmolality and AVP in PE-exposed rats was parallel to, but shifted to the right of, the control rats, indicating an increase in osmotic threshold for AVP release. Pituitary AVP was reduced by 13% and hypothalamic AVP mRNA content was reduced by 35% in PE-exposed rats. Our data suggest that PE exposure can cause a permanent condition of a mild partial central diabetes insipidus.

This study was conducted to determine whether 100% FiO2 during hemorrhage would improve maintenance of mean arterial blood pressure and to assess the cardiovascular, arginine vasopressin, and renin-angiotensin system roles in the response. This also allowed evaluation of FiO2 effects on the baroreceptor control of these hormone systems. Six conscious female goats were hemorrhaged (0.5 mL x kg(-1) x min(-1)) for 30 minutes, while breathing 11%, 21%, or 100% O2. Mean arterial blood pressure was maintained only when the goats breathed 100% O2. FiO2 did not affect O2 consumption or delivery during hemorrhage. Increases in renin and arginine vasopressin were equal or reduced with 100% FiO2 and therefore did not contribute to the improved mean arterial blood pressure maintenance. Inspiration of 100% FiO2 during hemorrhage, therefore, may improve perfusion pressure with no changes in O2 consumption or delivery. Also, 100% FiO2 eliminated the negative correlation between both hormones and right atrial pressure, suggesting altered baroreceptor control of the hormones.

Fluid handling is known to differ between males and females. Interactions between sex steroids such as estrogen with fluid regulating hormones like vasopressin (VP) are likely key to establishing these differences. Research has identified estrogen receptor (ER) alpha and Beta in renal tissue which may affect renal fluid handling. Thus, this study hypothesized that chronic ethanol exposure would elicit different alterations to water load excretion between male and female Sprague Dawley (SD) rats due to changes in renal VP V2 receptor (V2R) or ER mRNA expression. Therefore, in this study we compared 120 minute excretion of a 2% Body Weight (BW) water load between male control (n=6) and ethanol-fed (n=14) rats, and female control (n=26) and ethanol-fed (n=26) rats. Additionally renal papilla mRNA expression of V2R, ERalpha, and ERbeta was compared between male control (n=S) and ethanol-fed (n=I 5) rats, and female control (n=12) and ethanol-fed (n=17) rats. Female ethanol fed rats showed a 16% reduction in water load excretion (p

Unwanted scar tissue after surgical procedures remains a central problem in medicine. Nowhere is this problem more evident than within the pediatric airway, where excess scarring, termed subglottic stenosis, can compromise breathing. Recent advances in molecular biology have focused on ways to decrease scar formation through understanding of the wound repair process. Transforming growth factor beta (TFGbeta) plays a central role in this pathway. Ferrets serve as an ideal model for the pediatric airway, and reproduction of subglottic stenosis in ferrets is possible. However, ferret cytokine profiles have not been established. In this study, we characterized the presence and nucleotide sequence of the TGFbeta1 and 2 genes in ferrets by using total RNA isolated from airways. Amino acid sequence homology between human and ferret was determined to be 96.6% for TGFbeta1 and 99.3% for TGFbeta2. Given the nearly total homology between TGFbetas of ferret and human origin, the ferret may serve as an ideal model for future molecular studies.

Reference values of blood volume (BV) and plasma volume (PV) of animal species are given as functions of body weight and gender specification generally is not given. Considering the common observation of a decreased hematocrit (Hct) in the females of many species, the BV, the PV, or both must differ between genders. The present study was performed to determine the magnitude of those differences. We measured Hct and PV in 24 female and 23 male Sprague-Dawley rats in their 12th week of life. The rats were surgically prepared with indwelling femoral arterial catheters 4 d prior to the determination of BV. Evan's Blue dye dilution was used to determine PV in conscious, quietly resting animals. BV was calculated as PV/(1-Hct). Mean Hct was 2% lower in female rats than males, and PV (mean +/- 1 standard deviation) was 4.86 +/- 0.54 ml/100 g in females compared with 4.12 +/- 0.32 ml/100 g in males. Calculated BV in female rats was 7.84 +/- 0.70 ml/100 g compared with 6.86 +/- 0.53 ml/100 g in males. When precise estimates of BV or PV are needed for research or dosing purposes, gender differences of 18% for PV and 14% for BV must be considered. In addition, species other than the rat may have similar discrepancies between sexes, and the prudent investigator must determine individual volume assessments of both sexes before assumptions of BV and PV for a species can be made.

Arginine vasopressin (AVP) synthesis, storage and osmotically stimulated release are reduced in young adult rats exposed prenatally to ethanol (PE). Whether the reduced release of AVP to the osmotic stimulus is due to impairment of the vasopressin system or specifically to an osmoreceptor mediated release is not known. The present experiments were done, therefore, to determine if a hemorrhage-induced AVP response would also be diminished in PE exposed rats. Pregnant rats were fed either a control liquid diet (no prenatal ethanol, NPE) or a liquid diet with 35% of the calories from ethanol from day 7–21 of pregnancy. Offspring were weaned at 3 weeks of life. At 11 weeks of age femoral arterial catheters were surgically placed, and blood volumes determined at 12 weeks. Three days later, two hemorrhages of 10% of the blood volume were performed with samples taken prior to and 10 minutes after the hemorrhages. Following a 20% blood loss, plasma AVP was 19% higher in NPE rats than in the PE rats despite no differences in mean arterial blood pressure. Also, hypothalamic AVP mRNA and pituitary AVP content were reduced in PE rats. Furthermore, confirming an earlier report of gender difference in AVP release, the hemorrhage-induced hormone response was two-fold greater in female rats than male rats regardless of previous ethanol exposure. These studies demonstrate that the AVP response to hemorrhage is reduced in PE rats independent of differences in MABP. The data are compatible with a theory of a reduced number of hemorrhage responsive vasopressinergic neurons capable of stimulated AVP release in PE rats.

This study was conducted to determine whether 100% FiO2 during hemorrhage would improve maintenance of mean arterial blood pressure and to assess the cardiovascular, arginine vasopressin, and renin-angiotensin system roles in the response. This also allowed evaluation of FiO2 effects on the baroreceptor control of these hormone systems. Six conscious female goats were hemorrhaged (0.5 mL x kg(-1) x min(-1)) for 30 minutes, while breathing 11%, 21%, or 100% O2. Mean arterial blood pressure was maintained only when the goats breathed 100% O2. FiO2 did not affect O2 consumption or delivery during hemorrhage. Increases in renin and arginine vasopressin were equal or reduced with 100% FiO2 and therefore did not contribute to the improved mean arterial blood pressure maintenance. Inspiration of 100% FiO2 during hemorrhage, therefore, may improve perfusion pressure with no changes in O2 consumption or delivery. Also, 100% FiO2 eliminated the negative correlation between both hormones and right atrial pressure, suggesting altered baroreceptor control of the hormones.

Estrogen and progesterone interference with renal actions of arginine vasopressin (AVP) has been shown. Thus we hypothesized that women will have a higher water turnover than men and that the greatest difference will be during the luteal phase of the menstrual cycle. Seven men (32 ± 3 yr) and six women (33 ± 2 yr) drank 12 ml water/kg lean body mass on different days at 0800 and at 2000 following 10 h of fast and a standardized meal at 0600 and 1800. Women participated on days 4–11 and 19–25 of the menstrual cycle. Initial urine and plasma osmolalities and urine flow rates were similar in all experiments. The cumulative urine voided over 3 h following the morning drink was less in men (73 ± 12% of the water load) compared with women in either the follicular (100 ± 3%) or luteal phases (102 ± 10%) of the menstrual cycle. Nighttime values (30–43% of the water load) were lower in all experiments and were not different between sexes or menstrual cycle phases. Plasma AVP was higher at night and may contribute to this diurnal response. The data are generally consistent with the stated hypothesis; however, possibly owing to the greatly reduced urine flow in both sexes at night, a difference between sexes was not observed at that time.

Introduction: Recent studies have identified blood vessels as sites of arginine vasopressin (AVP) synthesis. This study explores human mesenteric blood vessels in an attempt to isolate and quantitate AVP and V1 receptor mRNA and correlate these with several parameters. Methods: Paired mesenteric blood vessels (artery and vein) were harvested (IRB approval). RNA was extracted from homogenized vessels, subjected to reverse transcription, and specific primers were used to amplify cDNA corresponding to either AVP or the V1 receptor and beta actin. TaqMan probes with FAM or Texas Red Fluorophores and black hole quenchers were used to signal real-time production of PCR products and quantify specific mRNA sequences. Results: Twelve patients of age 55 years (31–72 yrs.) were studied (7 male, 5 female). AVP mRNA was identified in 12/12 arteries and 10/12 veins (0.23 ± 0.10 [s.e.] in arteries vs. 0.18 ± 0.09 arbitrary units of AVP mRNA/actin mRNA in veins; p = NS). V1R mRNA was identified in 12/12 arteries and 8/11 veins (4.3 ± 1.02 artery vs. 1.56 ± 0.7 V1R mRNA/actin vein; p = 0.0244). Arterial and venous AVP mRNA correlated negatively with age (p = 0.0028 and p = 0.0132, respectively). Arterial and venous AVP mRNA showed significant positive correlation (p = 0.0141). Arterial V1R mRNA tended to be greater in males than females (5.73 ± 1.29 vs. 2.3 ± 0.94 arbitrary units of V1R mRNA/actin mRNA; p = 0.057). However, arterial V1R mRNA was strongly positively correlated with diastolic blood pressure (r = 0.70, p = 0.0112) and males had a higher diastolic pressure than females (79.4 ± 4.56 vs. 63.8 ± 3.3 mmHg, p = 0.019). Conclusions: Although AVP synthesis is similar in mesenteric arteries and veins, V1R synthesis is higher in arteries. The negative correlation between both arterial and venous AVP synthesis and age may result from known higher serum AVP associated with aging. AVP synthesis in arteries and veins seems to rise and fall together and there is no apparent correlation between local AVP synthesis and synthesis of V1R. Interestingly, V1R synthesis in arteries is positively correlated with diastolic blood pressure and tends to be higher in male than female patients. Enhanced V1R synthesis in male arteries may predispose to hypertension in the male gender.

Urinary excretion rates of antidiuretic hormone were determined by radioimmunoassay in children with bacterial (6) and viral (11) meningitis, and in children with other febrile illnesses (7). These values were compared to normal data obtained from 50 healthy, normally hydrated children ranging in age from 1 week to 9 years. Plasma sodium concentrations were measured in the sick children; urine osmolality and creatinine concentrations were measured in all children. Upon admission, all children with bacterial meningitis and 64% of those with viral meningitis had urinary antidiuretic hormone excretion rates greater than 2 S.D. above values obtained from age-matched controls. Fifty-seven percent of children with other febrile illnesses had similarly elevated antidiuretic hormone values; however, only in the bacterial and viral meningitis groups were antidiuretic hormone excretion rates inappropriate because they occurred when serum sodium concentrations were found to be normal or low normal (i.e., 136 +/- 2 mEq/L and 137 +/- 1 mEq/L, respectively). The average serum sodium in the group with other febrile illnesses was higher (146 +/- 5 mEq/L; p less than 0.05) and could represent an appropriate stimulus for antidiuretic hormone release. In spite of high levels of antidiuretic hormone, most viral meningitis patients did not concentrate their urine, probably because all except 2 were younger than 2 months of age. We conclude that viral meningitis, like bacterial meningitis, frequently is associated with inappropriate antidiuretic hormone secretion; however, most children with viral meningitis may be protected from developing hyponatremia because of their inability to concentrate their urine.