Odor of urine

As the name implies, the odor of urine in maple syrup urine disease (brancbed-chain ketonuria) suggests maple symp or burnt sugar. The biochemical defect involves the a-keto acid decarboxylase complex (reaction 2, Figure 30-19). Plasma and urinary levels of leucine, isoleucine, valine, a-keto acids, and a-hydroxy acids (reduced a-keto acids) are elevated. The mechanism of toxicity is unknown. Early diagnosis, especially prior to 1 week of age, employs enzymatic analysis. Prompt replacement of dietary protein by an amino acid mixture that lacks leucine, isoleucine, and valine averts brain damage and early mortality. 

Kraemer RJ. Cranberry juice and the reduction of ammoniacal odor of urine. Southwest Med 1964 45 211-212. 

The appearance (color and odor) of urine itself can be helpful, a darkening from the pale normal straw color indi-... 

Ammoniacal fermentation, or alkalinization and decomposition of urine, is responsible for the foul odor of urine (Kraemer, 1964). The results of one study (Kraemer, 1964) found that a single dose of 16 oz of cranberry juice lowered the urine pH of six men with chronic urinary tract disorders, and decreased ammoniacal odor and turbidity. The urine pH of five of six men free of urinary tract infections was also lowered with this dose. In another study (DuGan and Cardaciotto, 1966), hospital personnel noted a decrease in urine odor in the geriatric wards of a nursing home, but a change in urine pH or change in ammonia levels in the air could not be detected. Other subiective... 

Why does eating asparagus produce bad-smelling urine Asparagus contains the amino acid methionine, which is metabolized in the body to produce methyl mercaptan. The peculiar odor of urine produced after consuming asparagus is caused by the methyl mercaptan excreted from the body in urine. 

Sniffing time of odors of urine, feces and mid-ventral gland secretion of conspecifics of own and opposite sex was examined in a two-stimulus test (Beauchamp, 1973 Johnston, 1981) the order of testing with different odors varied across subjects. There were at least 48 hours between two tests on the same subject. Technically, the procedure consisted of presentation of a pair of stimuli applied on cotton swabs that were placed in glass tubes (internal diameter 0.5 cm.) at a depth of 0.5 cm. from the open end. A pair of tubes, 4 cm apart, were inserted approximately 1 cm. into the cage through the wire lid. A new pair of glass tubes was used for each presentation. 

Thiolane is a colorless, water-insoluble hquid of bp 121 °C. It has a distinctive odor similar to that of town gas. In combination with other compounds, it is responsible for the typical odor of urine after consumption of asparagus. 

Blissitt M.J., Bland K.P. and Cottrell D.F. (1990). Discrimination between the odors of fresh estrous and non-estrous ewe urine by rams. Appl Anim Behav Sci 25, 51-60. 

Schellinck H.M., West A.M. and Brown R.E. (1992). Rats can discriminate between the urine odors of genetically identical mice maintained on different diets. Physiol Behav 51, 1079-1082. 

Yalcin, S.S., Tekinalp, G. and Ozalp, I. (1999) Peculiar odor of traditional food and maple syrup urine disease. Pediatr. Int. 41, 108-109. 

Schellinck, H.M., Slotnick, B.M. and Brown, R.E. (1997) Odors of individuality originating from the major histocompatibility complex are masked by diet cues in the urine of rats. Anim. Learn. Behav. 25, 193-199. 

An investigation of the stereochemistry of the urinary substances eliciting intermale aggression in the house mouse established that (l ,7.R)-3,4-dehydro-exo-brevicomin is present in the urine. Due to extremely facile racemization under very mild conditions, it was concluded that 2-sec-butyl-4,5-dihydrothi-azole 2 it is present in the urine as the racemate. It was suggested that the acidity of mouse urine probably promotes racemization of the optically active compound derived biosynthetically from an amino acid [36]. The observation that female house mice prefer the urinary odors of males uninfected by the intestinal nematode Heligmosomoidespolygyrus suggests that urine may also be important in conveying information on the infection status of males [37]. 

A 9-week-old boy, healthy at birth, begins to develop symptoms of ketoacidosis, vomiting, lethargy, seizures and hypertonia. Urine has characteristic odor of maple syrup. 

Mice are able actively to seek or avoid priming pheromones that modulate their ovarian cycle and onset of puberty. Peripubertal female mice avoid the urine odor of adult males, known to accelerate puberty in females, and are more attracted to the odor of grouped adult females. This behavior is particularly effective because the active space of the (almost) non-volatile male pheromone is small, and prolonged exposure is required for the effect to occur (Coppola and O Connell, 1988). Likewise, prepubertal female mice do not urinate near urine marks of adult males, while grouped, estrous, and diestrous adult females do. Such behavior may help young females to avoid exposure to male odors until they reach puberty. This way they would be protected from mating too early, and their eventual reproductive success would be enhanced (Drickamer, 1989a). 

The VNO is extremely important in mediating endocrine responses to primer pheromones. Puberty acceleration in female rats by male urine odors can be prevented by electrolytic damage to the vomeronasal nerve. Also, effects of male urine odor such as shortening of the estrus cycle (see Ch. 8) can be eliminated by section of the vomeronasal nerve, or bilateral electrocoagulation of the accessory olfactory bulb (Sanchez-Criado, 1982). In rats, the odor of males stimulates ovulation in females, an effect that is lost if the VNO is extirpated (Johns etal., 1978). Female prairie voles, M. ochrogaster, respond to odors from males with reproductive activation. Surgical removal of the VNO from adult females impedes this reproductive activation by the stud male. The weights of the uterus and the ovaries of these females were lower than those of normal or sham-operated individuals. However, the females without a VNO were still able to locate food by chemical cues (Lepri and Wysocki, 1987). 

In isolated male mice, own odor regulates the amount of urine deposited in marking. If it is present, they mark less, while clean surfaces and also other males urine trigger more frequent marking (Daumae and Kimura, 1986). In our laboratory experiments, students are impressed by how a mouse stops at a clean tile in the middle of a soiled open field. A scent-the-habitat function for odors from both sexes has been assumed for the gland secretions in the brushtail possum, Trichosurus vulpecula, since no sex differences in chemical composition were found (Woolhouse etal., 1994). 

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