Maryse Chopineau

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In order to localize the epitopes of equine chorionic gonadotropin (eCG) involved in interaction with luteinizing hormone (LH) and follicle-stimulating hormone (FSH) receptors, we used 14 monoclonal anti-eCG antibodies (mAbs). Different effects of these mAbs on the bioactivities of eCG were observed in in vitro bioassays, but the effects of each mAb on the(More)
Although donkey luteinizing hormone exhibits a very high degree of amino acid sequence identity with horse LH, its FSH activity in non-equine species is tenfold lower. The coding regions of the common zebra (Equus burchelli) glycoprotein hormone alpha-subunit and LH beta-subunit transcripts were cloned by reverse transcription-PCR from pituitary gland RNA(More)
The coding regions of the horse (Equus caballus) and donkey (E. asinus) luteinizing hormone (LH) beta-subunit transcripts were cloned from pituitary gland RNA, in order to investigate their relationships to the corresponding equine chorionic gonadotropin (CG) beta-subunits and to further understand the unusual receptor-binding properties of equine LH and(More)
Horse (Equus caballus) luteinizing hormone (eLH) and chorionic gonadotrophin (eCG), which have the same amino acid sequence, are unusual in that, although they express only LH activity in equids, they express dual LH and FSH activities in all other species tested. Donkey (Equus asinus) LH (dkLH) and CG (dkCG), which also share an identical peptide backbone,(More)
Luteal steroids are necessary to maintain the first 70-90 days of pregnancy in the mare. At 35 days postovulation, the resurgence of the primary corpus luteum (CL) coincides with the secretion of the fetal hormone eCG. In order to study the responsiveness of the primary CL to eCG, we have examined levels of luteal equine LH/CG receptors (eLH/CG-R) mRNAs by(More)
Reverse transcription-PCR was used to clone the coding region of the donkey (Equus asinus) glycoprotein hormone alpha-subunit transcript from pituitary gland RNA. The donkey alpha-subunit sequence demonstrated considerable identity with the horse (97% at the nucleotide level), confirming the very close evolutionary linkage between these two species. The(More)
The dual LH and FSH activity of the equine LH (eLH)/equine chorionic gonadotropin (eCG) in heterologous species makes eLH/CG a good model to study structure/function relationships of gonadotropins. In order to bypass the problem of intracellular association of the heterodimer, a recombinant single-chain beta alpha eLH/CG was used to identify sequences in(More)
The C-terminal region of the beta subunit of the human chorionic gonadotrophin (hCG) is implied in heterodimer stability (beta26-110 disulphide bridge), in vitro LH bioactivity (region beta102-110) and in in vivo LH bioactivity (beta CTP). Like the hCG beta, the equine eLH and eCG beta subunits, also possess a C-terminal extension (CTP). But, in contrast to(More)
Hormonal changes associated with pubertal development in a breed of pig exhibiting early puberty were determined. In Expt 1, blood from prepubertal Meishan gilts was collected at about 1 (n = 5), 10 (n = 5), 20 (n = 4), 30 (n = 5), 50 (n = 5), 70 (n = 10), 80 (n = 10) and 90 (n = 7) days of age. In Expt 2, females were sampled between 99 and 116 days of age(More)
Pituitary equine luteinizing hormone (eLH) and fetal chorionic gonadotrophin (eCG) have identical polypeptidic chains, but different linked carbohydrates. In equine tissues, eCG and eLH bind only to the LH/CG receptor (eLH/CG-R) and have no FSH activity. However, radio-receptor assays on equine luteal or testicular tissues have shown that eCG binds to the(More)