Influence of gender on the diurnal variation of urine production and micturition characteristics of the rat

Abstract

The diurnal variation in the frequency/volume characteristics of male and female conscious rats was evaluated with reference to fluid consumption and urine production. Baseline values of the micturition volume and frequency of nine male and 10 female SD adult rats were measured over a 24-hour time period. The level of initial hydration conditions was standardized with 5 ml of water administered orally. With animals in a metabolism chamber having free access to water, the total volume of water consumed, the frequency/volume characteristics during micturition and the urine production rate were derived from the measurements of voided volume as detected by a digital balance. To establish reliability of measurements two separate micturition studies were done per rat at an interval of 1 week. Mean frequency of micturition and mean volume voided per micturition and urine production rate were computed in 3-hour time bins and represented over the 24-hour period. In addition the mean values of the number of micturitions and mean micturated volumes during the day/dark cycle were evaluated. The results show significant gender specificity in water consumption, urine production, and diurnal variations in micturition frequency/volume characteristics. Females consistently consume significantly larger amounts of water (83%) than males while urine production rate was correspondingly higher in females. It is concluded that water consumption and urine production are gender-specific. Because higher volumes of water are imbibed by females than males, the frequency/volume characteristic of micturition in the rat is also gender-specific. Data suggest that the volume voided per micturition depends on the urine production rate.

Gender differences in kidney function

“…Finally, the recently described gender differences in diuretic, natriuretic, and kaliuretic response to furosemide in rats (F>M) could be explained by the lower abundance of NKCC2 transporter in the apical membrane of F TALH [29]. Besides NKCC2, a few other transports/transporters of inorganic substances, which may contribute to dissimilar urine production in M and F rats and mice [124,216], may be affected by sex hormones, but these transporters have not been well studied, and the relevant gender differences in their activity/expression have thus far not been reported (not listed in Table 3). For example, (1) ovariectomy in F rats resulted in increased urinary excretion of calcium (Ca 2+ ) [175], possibly due to downregulation of calbindin-D-28k, a putative Ca 2+ ferry protein in the distal tubule cells [52]; this effect was ameliorated by estradiol treatment and thus may explain an increased loss of Ca 2+ in the urine after menopause in women.…”

“…A higher glomerular capillary pressure due to lower vascular resistance in the M kidney may contribute to the hyperfiltrationinduced damage to the nephron and exacerbate renal disease ( [161], and references therein). In spite of having a lower GFR, F rats (and mice) exhibited higher urine production, possibly due to higher water consumption [124,216], but the roles of various transporters of inorganic and organic substances and water channels in this sex-dependent urine volume excretion have not been well investigated. A few studies, however, point to a complexity of this problem.…”

“…(e) By immunoelectron microscopy, ER were found in the nuclei of proximal tubule cells in both M and F rats [62], whereas in tissue sections of rat and mouse kidneys, AR were detected by immunocytochemistry in the nuclei of distal nephron [246]. (f) In the cytosolic fraction of mouse kidney cortex and cultured proximal tubule cells, AR were detected by binding assay of 3 H-dihydrotestosterone (DHT) [176], and (g) in human kidneys, ERβ were localized by immunocytochemistry to the collecting duct in M [255] or by in situ hybridization in the M and F cortex and medulla PT and DT cells that appear after puberty [100,143,161,169,177,194,219] Size of kidney cortex Rat F < M Androgen-induced hypertrophy of PT [22,177] Size of PT cells [22,161,194] Urine production Rat, mouse F > M Higher water consumption in F [124,216,271] Urine protein Rat, mouse F < M Androgen-dependent production and secretion of α-and β-microglobulins in PT and, possibly, a higher rate of endocytosis in F [4,102,194] Urine angiotensinogen Rat F < M Androgen-stimulated production and secretion of angiotensinogen (transport via exocytosis in PT?) [270] Urine vasopressin Rat, human F < M Reflects the plasma vasopressin levels (F < M).…”

Circadian variation of voided volume in normal school-age children

“…Population averages of output rates for urine and osmoles Individual rates for output of urine, and of osmoles, can be plotted on a time-scale to render circadian variations, assuming the urine and osmole excretion to be constant in the intervals between voidings [18,20]. Hourly averages of all individual rates, expressed per kg body weight, then render the circadian periodicity of the rates for urine and osmole excretion for the population.…”

Neuroanatomic and behavioral correlates of urinary dysfunction induced by vaginal distension in rats

“…The metabolic cage has also been widely used to study micturition in awake animals (8,53). In this cage, the urine slips on the wall of the cage to the urine container.…”