Fate of receptor-bound human chorionic gonadotrophin in pseudopregnant rat ovaries perfused in vitro.
Pseudopregnant rats were injected with [125I] hCG, anaesthesized 1 h later and after cannulation of the aorta the ovaries were isolated and perfused with Gey & Gey buffer containing 0.2% BSA. The release of radioactivity was monitored for 2 h and analyzed by gel filtration. Five to ten per cent of the radioactivity was released within 2 h and represented small molecular weight peptides and iodotyrosine and [125I]hCG. Analysis of the ovarian radioactivity prior to and after perfusion revealed that virtually all hCG was receptor-bound. Loading the medium with unlabelled hCG displaced [125I]hCG from the receptor but did not enhance its degradation. Histological examination showed that the ovarian tissues were still intact after the 2 h perfusion. Immunohistochemical studies revealed a localization of the hCG at the cell periphery both prior to and after perfusion. These results provide evidence showing that the rate of internalization of receptor-hCG complexes in rat luteal cells is slow in vivo.
Rajaniemi
H
H
Sogn
J
J
Holmes
P
P
Källfelt
B
B
Janson
P O
PO
D000818:Animals; D002850:Chromatography, Gel; D005260:Female; D007124:Immunoenzyme Techniques; D010053:Ovary / Q000378:metabolism*; D010477:Perfusion; D011374:Progesterone / Q000378:metabolism; D011555:Pseudopregnancy / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains; D011956:Receptors, Cell Surface / Q000378:metabolism*; D011974:Receptors, LH
D011956:Receptors, Cell Surface; D011974:Receptors, LH; D011374:Progesterone