Passive permeability of ovine amnion and allantois to chloride--gestational changes.
The passive permeability to 36Cl of isolated pieces of amnion (112), amniochorion (41) and allantois (54) from 55 pregnant ewes was studied in vitro. There was a significant decrease in the permeability coefficient (K) with increasing age in both amnion and allantois when samples from two age groups (72 to 109; 110 to 147 days of gestation) were analysed. There was a highly significant correlation (P less than 0.001) between amnion permeability and amniotic fluid [Cl-], but none between allantoic permeability and allantoic fluid [Cl-]. Amniotic fluid osmolality decreased significantly over the last third of gestation and was significantly correlated with amniotic fluid [Cl-]. Allantoic fluid osmolality increased with age and did not correlate with allantoic fluid [Cl-]. The anion exchange blocker, SITS, significantly decreased K in the amnion in the younger age group, suggesting that anion exchange through cell membranes may be one route of Cl- movement through the young amnion. The results suggest that the permeability of the amnion may play a role in the regulation of the composition of amniotic but not allantoic fluid in sheep.
Wintour
E M
EM
Department of Physiology, University of Melbourne, Parkville, Australia.
Lingwood
B E
BE
Towstoless
M K
MK
D000482:Allantois / Q000378:metabolism*; D000650:Amnion / Q000378:metabolism*; D000653:Amniotic Fluid / Q000032:analysis; D000818:Animals; D002712:Chlorides / Q000378:metabolism*; D005321:Extraembryonic Membranes / Q000378:metabolism*; D005260:Female; D009994:Osmolar Concentration; D010539:Permeability; D011247:Pregnancy; D012756:Sheep; D013997:Time Factors
D002712:Chlorides