The influence of urease activity on N distribution and losses after foliar urea application was investigated using wild-type and transgenic potato (Solanum tuberosum cv Désirée) plants in which urease activity was down-regulated. A good correlation between urease activity and N urea metabolism (NH3 accumulation) was found. The general accumulation of ammonium in leaves treated with urea indicat...

High protein intakes elevate plasma urea and ammonia concentrations and this can be negatively associated with plasma progesterone concentrations in cows (Jordan and Swanson 1979; Jordan et al. 1983). Low plasma progesterone concentrations may compromise embryo survival and there are reports of negative relationships between protein intake and conception rate in dairy cattle (eg Jordan and Swan...

Plasma urea and creatinine concentrations and urea and creatinine clearances and excretion were measured in a sample of 40 infants of 25*5-33 weeks' gestation, birth weight 720-2000 g, between the ages of 0 5 and 33 days. Creatinine excretion rate was between 60 and 120 gmol/kg/day in the first five postnatal weeks (mean 90.5) and was independent of sex or growth retardation. This can be used i...

The excessive use of nitrogen (N) fertilizers in sustaining high rice yields due to N dynamics in tropical acid soils not only is economically unsustainable but also causes environmental pollution. The objective of this study was to coapply biochar and urea to improve soil chemical properties and productivity of rice. Biochar (5 t ha(-1)) and different rates of urea (100%, 75%, 50%, 25%, and 0%...

MAUIDE, DAVID L., AND LAURENCE G. WESSON, JR. Renal wuter reabsorption during saline and urea osmotic diuresis in the dog. Am. J. Physiol. 205 (3) : 477-482. rg63.-Free water reabsorption (TWC) was measured in conscious dogs during a longterm, reasonably steady-state osmotic diuresis induced either by sodium salts or by urea. After 4 to 8 hr the original solute was partially replaced by urea or...

osmolality is decreased from 1,650 to 305 mosM. Incubation of slices in Ca2+-free media containing 2 mM EGTA largely abolished this action of osmolality on cAMP, whereas exclusion of Mg2+ or K+ from the incubation media was without effect. Addition of Ca21 to Ca2+-deprived inner medulla incubated at 750 mosM (175 mM Na+, 380 mM urea) significantly increased tissue cAMP and media prostaglandin (...

BACKGROUND Nitrogen absorption from the large intestine is considered of limited value for supporting body protein synthesis in animals and humans, but it may be of benefit when the dietary supply of nitrogen for synthesis of dispensable amino acids (DAAs) is deficient. OBJECTIVE A whole-body nitrogen balance study was conducted to evaluate the impact of nitrogen absorption from the large int...

Incubation experiment was conducted on four soil types in Nigeria using cattle dung (CD) at the rate of 2.5g/kg soil ( 5 t ha), Urea fertilizer at the rate of 0.1g/kg soil ( 200 kg ha ) and cattle dung (2.5g/kg soil) combined with Urea 0.05g/kg soil (100 kg ha) as treatments. The objective of the experiment was to compare the rate of OC, NH4 – N, NO3 – N and available P release on soils selecte...

Urea kinetics were measured using prime/intermittent oral doses of [15N15N]urea, on five separate protocols in thirteen normal young women. Each woman underwent either two or three study protocols. Measurements were made at day 12 and day 22 of the menstrual cycle, whilst consuming their habitual protein intake in seven women not taking the contraceptive pill and in six women taking the contrac...