Urates and allantoic regulation in embryonic Japanese quail,Coturnix coturnix japonica

✍ Scribed by McNabb, Roger A.

• Publisher: John Wiley and Sons
• Year: 1986
• Tongue: English
• Weight: 679 KB
• Volume: 240
• Category: Article
• ISSN: 0022-104X
• DOI: 10.1002/jez.1402400103

✦ Synopsis

During embryonic development, allantoic fluid represents the shifting balance between renal excretion and reabsorption by chorioallantoic membranes. Allantoic contents of Na', K+, C1-, urate, pH, and water were followed over days 10-15 of the 16 day incubation. Water volume remained near 0.9 ml until day 13, then declined very rapidly. The pH declined more steadily, from 8 to 5.5. Contents of Naf and C1-fell regularly to final values 8048% below day 10. The Kf content changed differently and nearly doubled by day 13 but returned to day 10 values at the end. Urate content rose until day 13, then fell suddenly to low levels. This was due to the abrupt precipitation of most urate into masses not sampled by our method, so that after day 13, urate was underestimated (probably by 90-96%). Ion binding by urates was low (about 3% of Na+ and C1-, 10% of K f > and appeared to be nonspecific. The underestimate of urate contents means, however, that in late incubation about one third of allantoic Naf and 65-70% of K+ and C1-are bound to precipitated urate and do not appear in balance sheets of allantoic ions. These precipitated ions account for the significant amounts of Na' and Kf that remain in the allantoic remnant, left in the eggshell after hatching, but whose presence is not predicted by analysis of allantoic fluid.