Summary
We tested the hypothesis that urea transport in rainbow trout (Oncorhynchus mykiss) embryos is dependent, in part, on a bidirectional urea-transport protein. Acute exposure to phloretin and urea analogs [acetamide, thiourea, 1,(4-nitrophenyl)-2-thiourea] reversibly inhibited urea excretion from the embryos to the external water. Unidirectional urea influx was inhibited by acetamide and thiourea, with IC(50) values of 0.04 and 0.05 mmol l(−1), respectively. Influx of urea from the external water to the embryo tended to saturate at elevated external urea concentrations (V(max)=10.50 nmol g(−1) h(−1); K(m)=2 mmol l(−1)). At very high urea concentrations (20 mmol l(−1)), however, a second, non-saturable component was apparent. These results indicate that urea excretion in trout embryos is dependent, in part, on a phloretin-sensitive facilitated urea transporter similar to that reported in mammalian inner medullary collecting ducts and elasmobranch kidney.
- © 2000 by Company of Biologists
Article navigation
Related articles
Cited by...
More in this TOC section
Similar articles
Other journals from The Company of Biologists
Welcome to JEB’s new Editor Monica Daley
We are pleased to welcome Monica Daley to JEB’s Editorial team. Monica has had a long association with JEB before taking up her new role, overseeing peer review of neuromuscular physiology, terrestrial biomechanics and integrative physiology of locomotion.
In the field with Robyn Hetem
Continuing our fieldwork series, Robyn Hetem reflects on working with species ranging from aardvark to zebra, and the impact COVID-19 has had on fieldwork.
Read & Publish participation continues to grow
“It is particularly encouraging for early career researchers, as it allows them to display their research globally without the need to find costs to cover the open access option.”
Professor Fernando Montealegre-Z (University of Lincoln) shares his experience of publishing Open Access as part of our growing Read & Publish initiative. We now have over 150 institutions in 15 countries and four library consortia taking part – find out more and view our full list of participating institutions.
Nocturnal reef residents have deep-sea-like eyes
Fanny de Busserolles and colleagues from The University of Queensland have discovered that the eyes of nocturnal reef fish have multibank retinas, layers of photoreceptors, similar to the eyes of deep-sea fish that live in dim light conditions.
Mechanisms underlying gut microbiota–host interactions in insects
In their Review, Konstantin Schmidt and Philipp Engel summarise recent findings about the mechanisms involved in gut colonisation and the provisioning of beneficial effects in gut microbiota–insect symbiosis.