scholarly journals Expressing the quantity of urinary analytes: a discussion of some issues arising from the monitoring of the menstrual cycle

Open Health ◽  
2020 ◽  
Vol 1 (1) ◽  
pp. 1-20
Author(s):  
Simon Brown ◽  
Delwyn G. Cooke ◽  
Leonard F. Blackwell
Keyword(s):  
Menstrual Cycle ◽  
Specific Gravity ◽  
Excretion Rate ◽  
Urinary Metabolites ◽  
Reproductive Hormones ◽  
Creatinine Excretion ◽  
Urinary Creatinine ◽  
Urinary Specific Gravity ◽  
Excretion Rates ◽  
Kinetics Of

AbstractPractical domestic monitoring of the menstrual cycle requires measurements of urinary metabolites of reproductive hormones: oestrone glucuronide (E1G) and pregnanediol glucuronide (PdG). Data reported in the literature are expressed as (i) concentration, without or with either creatinine- or specific gravity correction, or (ii) excretion rates. This variation in such a fundamental issue prompts consideration of the relationships between the four measures. Because the menstrual cycle kinetics of E1G and PdG are complex, we consider measurements of urinary creatinine, urea, galactose, xylose and inulin which tend to be more stable. We show that uncorrected concentration measurements of these urinary analytes can be positively correlated, negatively correlated or uncorrelated with the serum concentration. Based on measurements of urinary creatinine concentrations, urinary specific gravity and creatinine excretion rates, we conclude that urinary analyte concentration are likely to be more reliable when creatinine-corrected rather than corrected using specific gravity, but that both are less reliable than measurements of the excretion rate. This has implications for the quantitation of any urinary analyte, but especially for the monitoring of the menstrual cycle in which changes in E1G and PdG from one day to the next can be physiologically significant for a woman monitoring her fertility.

scholarly journals Variability of Urinary Creatinine in Healthy Individuals

2021 ◽  
Vol 18 (6) ◽  
pp. 3166
Author(s):  
Gerd Sallsten ◽  
Lars Barregard
Keyword(s):  
Flow Rate ◽  
Excretion Rate ◽  
Time Of Day ◽  
Urinary Flow Rate ◽  
Urinary Flow ◽  
Diurnal Variability ◽  
Creatinine Excretion ◽  
Blood Samples ◽  
Urinary Creatinine ◽  
Creatinine Excretion Rate

Many urinary biomarkers are adjusted for dilution using creatinine or specific gravity. The aim was to evaluate the variability of creatinine excretion, in 24 h and spot samples, and to describe an openly available variability biobank. Urine and blood samples were collected from 60 healthy non-smoking adults, 29 men and 31 women. All urine was collected at six time points during two 24 h periods. Blood samples were also collected twice and stored frozen. Analyses of creatinine in urine was performed in fresh urine using an enzymatic method. For creatinine in urine, the intra-class correlation (ICC) was calculated for 24 h urine and spot samples. Diurnal variability was examined, as well as association with urinary flow rate. The creatinine excretion rate was lowest in overnight samples and relatively constant in the other five samples. The creatinine excretion rate in each individual was positively correlated with urinary flow rate. The creatinine concentration was highest in the overnight sample and at 09:30. For 24 h samples the ICC was 0.64, for overnight samples it was 0.5, and for all spot samples, it was much lower. The ICC for urinary creatinine depends on the time of day of sampling. Frozen samples from this variability biobank are open for researchers examining normal variability of their favorite biomarker(s).

scholarly journals Effects of sex and menstrual cycle on volume-regulatory responses to 24-h fluid restriction

2020 ◽  
Vol 319 (5) ◽  
pp. R560-R565
Author(s):  
Gabrielle E. W. Giersch ◽  
Abigail T. Colburn ◽  
Margaret C. Morrissey ◽  
Cody R. Butler ◽  
Michaela L. Pruchnicki ◽  
...  
Keyword(s):  
Menstrual Cycle ◽  
Specific Gravity ◽  
Body Mass ◽  
Urine Osmolality ◽  
Reproductive Hormones ◽  
Urine Specific Gravity ◽  
Fluid Restriction ◽  
Urine Color ◽  
Fluid Regulation ◽  
The Impact

Reproductive hormones have significant nonreproductive physiological effects, including altering fluid regulation. Our purpose was to explore the impact of sex and menstrual cycle (MC) phase on volume-regulatory responses to 24-h fluid restriction (24-h FR). Participants (men: n = 12, 20 ± 2 yr; women: n = 10, 20 ± 1 yr) were assigned two randomized and counterbalanced fluid prescriptions [Euhy: euhydrated, urine specific gravity (USG) < 1.020; Dehy: 24-h FR, USG > 1.020]. Men completed both (MEuhy, MDehy), while women completed both in the late-follicular ( days 10–13; FDehy, FEuhy) and midluteal ( days 18–22; LDehy, LEuhy) phases. We measured body mass, plasma and urine osmolality (Posm, Uosm), urine specific gravity (USG), urine color (Ucol), and serum copeptin; 24-h FR yielded mild dehydration without influence of sex or MC ( P > 0.05). Copeptin increased in men following Dehy (pre: 8.2 ± 5.2, post: 15.8 ± 12.6, P = 0.04) but not in women (FDehy pre: 4.3 ± 1.6, post: 10.5 ± 6.9, P = 0.06; LDehy pre: 5.6 ± 3.5, post: 10.4 ± 6.2, P = 0.16). In FDehy, Posm increased following FR (pre: 288 ± 2, post: 292 ± 1, P = 0.03) but not in men (pre: 292 ± 3, post: 293 ± 2, P = 0.46). No MC differences were observed between body mass loss, Posm, Uosm, USG, and copeptin ( P > 0.05). These results suggest that volume-regulatory responses to 24-h FR were present in men but not in women, without apparent effects of the menstrual cycle.

Alteration of renal function of rats following spaceflight

1998 ◽  
Vol 275 (4) ◽  
pp. R1058-R1065 ◽  
Author(s):  
Charles E. Wade ◽  
Emily Morey-Holton
Keyword(s):  
Renal Function ◽  
Excretion Rate ◽  
Free Water ◽  
Male Rats ◽  
Free Water Clearance ◽  
Creatinine Excretion ◽  
Flight Controls ◽  
Excretion Rates ◽  
Solute Excretion ◽  
Water Clearance

Following spaceflight, changes in renal function of humans have been suggested. To assess the effects of readaptation on renal function, urine was collected from male rats (∼245 g) over a 2-wk period following a 14-day spaceflight. Rats were assigned to three groups: flight animals ( n = 6), flight controls ( n = 6) housed in the flight cages on the ground, and vivarium controls ( n = 5) housed in standard shoe box cages. Animals were placed into individual metabolic cages for urine collection. Urine output was significantly increased for 3 days following flight. Excretion rates of Na+ and K+ were increased, resulting in an increased osmotic excretion rate. Creatinine excretion rate increased over the first two postflight days. Glomerular filtration rate increased immediately following spaceflight without changes in plasma creatinine, Na+, K+, or osmolality. Increased excretion of solute was thus the result of increased delivery and a decreased percent reabsorption of the filtered load. Osmolal clearance was increased immediately postflight while free water clearance was decreased. In growing rats, the diuresis after short-duration spaceflight is the result of an increase in solute excretion with an accompanying reduction in free water clearance.

scholarly journals Muscle mass determined from urinary creatinine excretion rate, and muscle performance in renal transplant recipients

2019 ◽  
Vol 10 (3) ◽  
pp. 621-629 ◽  
Author(s):  
Suzanne P. Stam ◽  
Michele F. Eisenga ◽  
Antonio W. Gomes‐Neto ◽  
Marco Londen ◽  
Vincent E. Meijer ◽  
...  
Keyword(s):  
Renal Transplant ◽  
Muscle Mass ◽  
Excretion Rate ◽  
Muscle Performance ◽  
Renal Transplant Recipients ◽  
Transplant Recipients ◽  
Creatinine Excretion ◽  
Urinary Creatinine ◽  
Urinary Creatinine Excretion ◽  
Creatinine Excretion Rate

scholarly journals Factors affecting urinary creatinine in heifers and cows1

2019 ◽  
Vol 3 (1) ◽  
pp. 532-540 ◽  
Author(s):  
Kimberly M Whittet ◽  
Andrea K Watson ◽  
Galen E Erickson ◽  
Terry J Klopfenstein
Keyword(s):  
Diurnal Variation ◽  
Body Condition Score ◽  
Urinary Metabolites ◽  
Purine Derivative ◽  
Creatinine Excretion ◽  
Urinary Creatinine ◽  
Factors Affecting ◽  
Condition Score ◽  
Fat Thickness ◽  
The Relationship

Abstract A series of total urine collections were conducted to evaluate the effects of age, diet, gestation, and body condition score (BCS) on urinary creatinine (UC) and purine derivative (PD) excretion in heifers and cows. For each collection, urine was collected over a 5-d period and composited by animal within day. Daily samples were analyzed for UC and PD concentration and averaged over the 5-d period. All animals were fed in individual stanchions at 2.0% of body weight (BW). To evaluate the relationship between age and UC excretion, 21 animals ranging from 5 to 80 months of age were fed a forage-based diet supplemented with dried distillers grains (DDG). Creatinine excretion (mg/kg BW) was not correlated with age (P = 0.37). To determine if diet alters UC, 11 heifers were sampled for two urine collection periods. In period 1, heifers were fed a forage-based diet supplemented with DDG. In period 2, heifers were fed a finishing diet (90% concentrate, 10% forage). Creatinine excretion (mg/kg BW) and PD:creatinine (PD:C) was greater (P = 0.01) for heifers when fed the forage-based diet than when fed the concentrate-based diet. Eleven cows fed a forage-based diet supplemented with DDG were sampled to determine the effect of gestation on urinary metabolites. Gestation did not affect UC (P = 0.42) or PD:C (P = 0.30). To evaluate the relationship between 12th rib fat thickness and metabolite excretion, 40 heifers were fed a common finishing diet. There was no relationship between UC (mg/kg BW; P = 0.28) or PD:UC (P = 0.47) and 12th rib fat thickness. To evaluate the relationship between BCS and UC, 11 cows were fed a forage diet supplemented with DDG. There was no relationship between BCS and UC (mg/kg BW; P = 0.99) or PD:C (P = 0.84). To evaluate daily and diurnal variation in UC, nine heifers were fed a forage diet supplemented with DDG. Seven of the heifers were fed a finishing diet (90% concentrate, 10% forage) in a second period. Urine was collected every 2 h from 0600 to 1800 hours. When expressed as mg/kg BW, UC excretion was not different across animals fed the forage-based (P = 0.40) or concentrate-based diet (P = 0.18). Stepwise regression indicated that at least 3 d of collection were required to estimate UC. Time within day and day within period effects were observed (P &lt; 0.01) for UC from 2-h interval samples. The UC varies with type of diet and diurnal variation is present. Variation among animals is relatively small.

scholarly journals Posttransplant muscle mass measured by urinary creatinine excretion rate predicts long-term outcomes after liver transplantation

2018 ◽  
Vol 19 (2) ◽  
pp. 540-550 ◽  
Author(s):  
Suzanne P. Stam ◽  
Maryse C. J. Osté ◽  
Michele F. Eisenga ◽  
Hans Blokzijl ◽  
Aad P. van den Berg ◽  
...  
Keyword(s):  
Liver Transplantation ◽  
Muscle Mass ◽  
Excretion Rate ◽  
Long Term Outcomes ◽  
Creatinine Excretion ◽  
Urinary Creatinine ◽  
Urinary Creatinine Excretion ◽  
Creatinine Excretion Rate

scholarly journals Urinary Creatinine Excretion Rate and Mortality in Persons With Coronary Artery Disease

Circulation ◽  
2010 ◽  
Vol 121 (11) ◽  
pp. 1295-1303 ◽  
Author(s):  
Joachim H. Ix ◽  
Ian H. de Boer ◽  
Christina L. Wassel ◽  
Michael H. Criqui ◽  
Michael G. Shlipak ◽  
...  
Keyword(s):  
Coronary Artery Disease ◽  
Coronary Artery ◽  
Excretion Rate ◽  
Creatinine Excretion ◽  
Urinary Creatinine ◽  
Artery Disease ◽  
Urinary Creatinine Excretion ◽  
Creatinine Excretion Rate

Urinary creatinine excretion in the ICU: low excretion does not mean inadequate collection

1993 ◽  
Vol 2 (6) ◽  
pp. 462-466 ◽  
Author(s):  
GR Pesola ◽  
I Akhavan ◽  
GC Carlon
Keyword(s):  
Body Weight ◽  
Actual Body ◽  
Excretion Rate ◽  
Lean Body Weight ◽  
Actual Body Weight ◽  
Creatinine Excretion ◽  
Urinary Creatinine ◽  
Group 2 ◽  
Urinary Creatinine Excretion ◽  
Creatinine Excretion Rate

BACKGROUND: It has been assumed that a urinary creatinine excretion rate of less than 10 mg/kg per day means an inadequately collected urine sample. OBJECTIVE: To determine the frequency of a urinary creatinine excretion rate of less than 10 mg/kg per day in intensive care unit patients with an adequately collected urine sample. METHOD: In a prospective study of creatinine excretion rates, 24-hour urine samples were evaluated for urinary creatinine in 209 critically ill patients with indwelling Foley catheters. Patients from three adult intensive care units in New York City were divided into two groups. Group 1 patients excreted less than 10 mg/kg per day of urinary creatinine, and group 2 patients excreted at least 10 mg/kg per day. Groups 1 and 2 were first evaluated by dividing the creatinine excretion data by actual body weight. Since actual body weight may overestimate body weight in the critically ill patient, data from groups 1 and 2 were also evaluated using lean body weight. RESULTS: Urinary creatinine excretion was less than 10 mg/kg per day in 36.8% of patients using actual body weight and 29.7% of patients adjusted for lean body weight. The average age of patients in group 1 was 74 +/- 17 years for both actual body weight and lean body weight. The average age of group 2 patients was 60 +/- 19 years for actual body weight and 62 +/- 19 years for lean body weight. There was a significant difference in age between group 1 and group 2 patients for both actual body weight and lean body weight. The proportion of female vs male patients with reduced creatinine excretion was significantly greater, whether the actual body weight or lean body weight adjustment was used. CONCLUSIONS: A urinary creatinine excretion rate of less than 10 mg/kg per day occurs in about one third of critically ill patients, who are more likely to be elderly and female.

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