Effects of calcium availability on the release of ovine choriomammotropin from cotyledonary cells incubated in vitro.
1. In this study, we examined the basal release of choriomammotropin (oCM) from monolayer cultures of cotyledonary cells obtained from ewes at different gestational ages. 2. oCM release increased with gestational age and displayed a similar profile to the concentration of oCM observed in maternal plasma. 3. Release of oCM was significantly (P less than 0.05; n = 9) increased in calcium-depleted medium, and by treatment with either phospholipase C (0.125 units/ml) or KCl (50 mM). 4. The calcium antagonist MgCl (12 mM) and the calcium channel-blocking agents verapamil (50 microM) and nefidipine (10 microM) all significantly stimulated oCM release. 5. These data are consistent with the suggestion that oCM release is inversely related to extracellular calcium concentration.
Burke
J L
JL
Department of Physiology, Monash University, Clayton, Australia.
Rice
G E
GE
Ralph
M M
MM
Thorburn
G D
GD
D000818:Animals; D001682:Biological Availability; D002118:Calcium / Q000378:metabolism / Q000502:physiology*; D002478:Cells, Cultured; D005260:Female; D010920:Placenta / Q000166:cytology / Q000378:metabolism*; D010928:Placental Lactogen / Q000378:metabolism*; D011247:Pregnancy; D012756:Sheep / Q000378:metabolism*; D013997:Time Factors
D010928:Placental Lactogen; D002118:Calcium