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

Abstract

During embryonic development, allantoic fluid represents the shifting balance between renal excretion and reabsorption by chorioallantoic membranes. Allantoic contents of Na+, K+, Cl-, 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 Na+ and Cl- fell regularly to final values 80-88% below day 10. The K+ 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 Cl-, 10% of K+) and appeared to be nonspecific. The underestimate of urate contents means, however, that in late incubation about one third of allantoic Na+ and 65-70% of K+ and Cl- 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 K+ that remain in the allantoic remnant, left in the eggshell after hatching, but whose presence is not predicted by analysis of allantoic fluid.

Vascular leakage in chick embryos after expression of a secreted binding protein for fibroblast growth factors

“…Injection into the allantoic sac proved an efficient route of transgene administration consistent with the known absorption of materials from the allantoic fluid. [34][35][36] Different reporter genes showed that expression was widespread in somites, primitive epithelia, blood vessels and neuroectodermal tissues. Furthermore, gene expression persisted for at least 96 h following microinjection of the plasmid vectors.…”

The effects of variation in egg water loss on the chick embryo and its fluid compartments

“…Evidence for this ion transport is the sharp decline in Na"*" and CI" ion concentrations seen in allantoic fluid McNabb, 1986). The volume of allantoic fluid declines also and is thought to be caused by the outside positive membrane potential set up by the movement of Na"*" ions Kyriakides and Simkiss, 1975).…”