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Effect of rising hCG levels on the human corpus luteum during early pregnancy.

https://arctichealth.org/en/permalink/ahliterature92541
Source
Hum Reprod. 2008 Dec;23(12):2775-81
Publication Type
Article
Date
Dec-2008
Author
Järvelä Ilkka Y
Ruokonen Aimo
Tekay Aydin
Author Affiliation
Department of Obstetrics and Gynecology, Oulu University Hospital, Oulu, Finland. ilkka.jarvela@oulu.fi
Source
Hum Reprod. 2008 Dec;23(12):2775-81
Date
Dec-2008
Language
English
Publication Type
Article
Keywords
17-alpha-Hydroxyprogesterone - blood
Adult
Chorionic Gonadotropin - physiology
Corpus Luteum - blood supply
Female
Humans
Ovary - blood supply - ultrasonography
Pregnancy
Pregnancy Trimester, First - physiology
Pregnancy-Associated Plasma Protein-A - metabolism
Progesterone - blood
Abstract
BACKGROUND: During early pregnancy, the most important task of the corpus luteum (CL) is to produce sufficient progesterone until the luteoplacental shift occurs. Progesterone production is closely related to the extensive vasculature surrounding and supplying the CL. The synthesis of both progesterone and factors controlling the vasculature in the CL is regulated by hCG, which is released initially at rising levels from the placenta. The primary aim of this research was to evaluate changes in the CL vasculature during early pregnancy. METHODS: Twenty naturally conceived pregnancies were examined weekly from weeks 5 to 11. At each visit, blood samples were obtained to determine the concentrations of hCG, progesterone and 17-OH progesterone (17-OHP). The vasculature in the ovaries was assessed using three-dimensional power Doppler ultrasonography. RESULTS: The vascular supply in the ovary containing the CL was greatest at week 5, and thereafter, declined continuously until week 11. The decrease in the vasculature correlated with the decrease in 17-OHP. Mean hCG levels reached a maximum at week 8, progesterone levels reached the nadir at week 7 and increased after that. CONCLUSIONS: Vasculature in the CL appears to be created already by the fifth week of pregnancy and it does not enlarge despite rising hCG levels. The activity of the CL during pregnancy may be measured non-invasively by assessing its vasculature with three-dimensional ultrasonography.
PubMed ID
18694877 View in PubMed
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Folliculogenesis, onset of puberty and fecundity of mink (Mustela vision Schreb) selectively bred for docility or aggressiveness.

https://arctichealth.org/en/permalink/ahliterature50887
Source
Theriogenology. 1998 Jun;49(8):1545-53
Publication Type
Article
Date
Jun-1998
Author
D V Klotchkov
O V Trapezov
A V Kharlamova
Author Affiliation
Laboratory of Evolutionary Genetics, Siberian Department, Russian Academy of Sciences, Novosibirsk, Russia.
Source
Theriogenology. 1998 Jun;49(8):1545-53
Date
Jun-1998
Language
English
Publication Type
Article
Keywords
Aggression - physiology - psychology
Animals
Behavior, Animal
Chorionic Gonadotropin - physiology
Epithelium - physiology
Female
Fertility
Histocytochemistry
Male
Mink - physiology
Ovarian Follicle - cytology - growth & development
Ovary - cytology
Research Support, Non-U.S. Gov't
Sexual Maturation
Uterus - cytology
Abstract
It has been suggested that selective breeding of animals for docile behavior is correlated with early onset of puberty and improved fertility. We wished to test the hypothesis that mink bred for docility would show earlier onset of puberty and greater fecundity than mink bred for aggressiveness. We used farm-raised, 7-mo-old mink females that had been selectively bred for 7 to 10 generations on the basis of behavior towards humans. Onset of puberty was estimated once (between 15 and 20 December) by vaginal smears and was said to start wtih preponderance of cornified epithelial cells in the cytological specimen. Fecundity was measured by litter size and rate of folliculogenesis, with and without hCG stimulation, by histomorphometric examination of ovaries and uteri. A total of 43/100 (43%) docile females achieved proestrus and estrus as compared to 16/136 (12%) of the aggressive ones. Overall pregnancy rate, survival to 5 d after whelping and litter size did not differ between the docile and aggressive females. Docile females showed significantly higher numbers (P
PubMed ID
10732018 View in PubMed
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Human chorionic gonadotrophin (CG)-induced down-regulation of the rat luteal LH/CG receptor results in part from the down-regulation of its synthesis, involving increased alternative processing of the primary transcript.

https://arctichealth.org/en/permalink/ahliterature64837
Source
J Mol Endocrinol. 1993 Apr;10(2):153-62
Publication Type
Article
Date
Apr-1993
Author
J T Lakkakorpi
E M Pietilä
J T Aatsinki
H J Rajaniemi
Author Affiliation
Biocenter, University of Oulu, Finland.
Source
J Mol Endocrinol. 1993 Apr;10(2):153-62
Date
Apr-1993
Language
English
Publication Type
Article
Keywords
Animals
Base Sequence
Blotting, Northern
Chorionic Gonadotropin - physiology
DNA, Single-Stranded
Densitometry
Down-Regulation
Female
Humans
Immunoblotting
Molecular Sequence Data
Ovary - metabolism
Polymerase Chain Reaction
Pseudopregnancy - metabolism
RNA Processing, Post-Transcriptional
RNA, Messenger - metabolism
Rats
Rats, Sprague-Dawley
Receptors, LH - genetics - metabolism
Research Support, Non-U.S. Gov't
Transcription, Genetic
Abstract
To elucidate the molecular mechanisms involved in the homologous regulation of LH/chorionic gonadotrophin (CG) receptors, the receptor and its mRNA levels were analysed in the same pseudopregnant rat ovarian samples after human (h)CG-induced down-regulation using a binding assay, ligand blotting, immunoblotting and Northern blotting together with the polymerase chain reaction (PCR). Treatment of the animals with 500 IU hCG resulted in a loss of 125I-labelled hCG binding and the 90 kDa receptor on the ligand and immunoblots within 12 and 24 h respectively, followed by a transient partial recovery on days 4 and 5, while a distinct decline occurred only on day 7 in the controls. Northern blots of total ovarian RNA, as probed with a 293 bp AvaI/HindIII fragment from the extracellular domain of PCR-generated full-length rat LH/CG receptor cDNA, revealed six major mRNAs of 7.0, 4.2, 2.8, 2.0, 1.4 and 1.1 kb. The 4.2 kb mRNA, which was the most abundant, possibly encodes the 90 kDa receptor, while the smaller species probably represent alternatively spliced forms of the LH/CG receptor pre-mRNA, as also supported by the finding that PCR produced three cDNA bands of 2.1, 2.0 and 1.8 kb when oligomers derived from the N and C termini of rat LH/CG receptor cDNA were used as primers and rat ovarian total RNA as a template. Treatment with hCG led to the down-regulation of all six mRNAs in a fashion parallel to the changes in receptor protein. No smaller receptor components capable of binding radiolabelled hCG or receptor antibody appeared on the ligand or immunoblots prior to or during down-regulation or the subsequent transient period of up-regulation, suggesting that the smaller mRNA species are translated in minute amounts in vivo or are not translated at all. Laser densitometric analysis of the Northern blots revealed that the amounts of the four smallest mRNA species increased during the period of down-regulation in relation to the 4.2 kb mRNA, and correspondingly decreased during the subsequent period of up-regulation, indicating changes in the alternative splicing of the primary transcript. The data suggest that hCG-induced transient down-regulation of the LH/CG receptor results in part from down-regulation of its mRNA levels, and that changes in alternative processing of the receptor pre-mRNA may play a regulatory role in the expression of functional LH/CG receptor during down- and up-regulation.
PubMed ID
8484864 View in PubMed
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