Properties of proteins binding plasma progesterone in pregnant Cape porcupines (Hystrix africaeaustralis).
The properties of progesterone-binding proteins in plasma of pregnant Cape porcupines were investigated using radiolabelled progesterone and either progesterone or cortisol as competing ligands as well as native plasma and heated (60 degrees C for 30 min) plasma. The results demonstrated that plasma from pregnant porcupines contains corticosteroid-binding globulin, but that it constitutes a significant portion of plasma progesterone-binding proteins only during the early stages of pregnancy. Corticosteroid-binding globulin of porcupines appears to be as heat labile as that of guinea-pigs. Concentrations of progesterone-binding proteins in plasma increased during pregnancy to reach concentrations at the eleventh week that were 25 times higher than those of progesterone; concentrations increased significantly (r2 = 0.88) with the increase in progesterone concentration. The results indicate that plasma progesterone-binding proteins in Cape porcupines (Old World hystricomorph) are similar in composition to those in guinea-pigs (New World hystricomorph).
Louw
A I
AI
Department of Biochemistry, University of Pretoria, South Africa.
van Wyk
V
V
van Aarde
R J
RJ
D000818:Animals; D005260:Female; D011247:Pregnancy; D011270:Pregnancy, Animal / Q000378:metabolism*; D011374:Progesterone / Q000378:metabolism*; D011376:Progesterone-Binding Globulin / Q000378:metabolism*; D011485:Protein Binding / Q000502:physiology; D012377:Rodentia / Q000378:metabolism*; D014156:Transcortin / Q000378:metabolism*
D011376:Progesterone-Binding Globulin; D011374:Progesterone; D014156:Transcortin