Table 1.

PH and ion concentrations in blood plasma, uterine fluid and epithelial cells during eggshell mineralisation [5]

	Blood plasma	Epithelial cells	Uterine fluid
			8 h PO	18 h PO
Ions	[mM]	[mM]	[mM]	[mM]
Ca2+	1.2	<0.0002	6	10
Na+	140	12	144	80
K+	4	139	12	60
HCO3-	23	12	60	110
pH	7.4	7.0-7.4	7.6	7.1
Cl-	130	4	71	45

The eggshell precursors are secreted in the uterine fluid where the eggshell mineralization daily takes place from 10 hours to 22 hours post ovulation (yolk entry in the oviduct). PO: post ovulation.