Colloidal effect of albumin on the placental lactogen and chorionic gonadotrophin releases from human term placental explants.
Albumin has been reported to stimulate the release of placental lactogen and chorionic gonadotrophin from human term placental explants within physiological concentrations. This study aimed at characterizing further its effect on the placental hormonal secretion. The placental lactogen and chorionic gonadotrophin secretory response of incubated explants to 5% albumin was reproduced by colloidal agents, i.e., dextran (4.5%) and polygelin (4%), indicating that a rise in colloidal osmotic pressure can elicit hormonal release from the syncytiotrophoblast. Their secretory effects were not modified by the absence of extracellular calcium or the presence of verapamil in the medium. The three agents also provoked a marked increase in (45)calcium outflow from preloaded and perifused explants that persisted in absence of extracellular calcium. These data indicate that the triggering effect of albumin on placental lactogen and chorionic gonadotrophin release can be partly reproduced by colloidal agents and is independent of extracellular calcium.
Lambot
N
N
Laboratory of Experimental Hormonology, Université Libre de Bruxelles, Brussels 1070, Belgium. nlambot@ulb.ac.be
Lebrun
P
P
Cirelli
N
N
Vanbellinghen
A M
AM
Delogne-Desnoeck
J
J
Graff
G
G
Meuris
S
S
D000418:Albumins / Q000737:chemistry*; D000818:Animals; D002118:Calcium / Q000737:chemistry / Q000378:metabolism; D002417:Cattle; D006063:Chorionic Gonadotropin / Q000737:chemistry*; D003102:Colloids / Q000737:chemistry*; D003911:Dextrans / Q000737:chemistry; D004305:Dose-Response Relationship, Drug; D006801:Humans; D010920:Placenta / Q000378:metabolism*; D010928:Placental Lactogen / Q000737:chemistry*; D012709:Serum Albumin / Q000378:metabolism; D013997:Time Factors; D014700:Verapamil / Q000737:chemistry
D000418:Albumins; D006063:Chorionic Gonadotropin; D003102:Colloids; D003911:Dextrans; D012709:Serum Albumin; D010928:Placental Lactogen; D014700:Verapamil; D002118:Calcium