Category Archives: Ovary

Luteotropic Hormone Receptors: DISCUSSION(6)

In the current study, treatment of animals with bromocriptine prevented the transient LH receptor mRNA peak between March 19 and 25 and reduced LH receptor mRNA levels below those of the pretreatment controls. This suggests a role for prolactin in regulation and maintenance of LH receptors. This hypothesis is indirectly supported by a number of studies showing that prolactin and/or placental lactogens increase LH receptor binding sites and LH receptor mRNA in the CL of other species. If present, the stimulatory effect of prolactin on mink LH receptors is transient, as it is not present during later gestation when prolactin levels are elevated and LH receptor mRNA remains constant.

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Luteotropic Hormone Receptors: c

DISCUSSION(3)

In Northern analysis, a single mink LH receptor mRNA transcript predominated over two much-weaker bands in mink ovary and testis. This is in contrast with findings in other species including the rat, mouse, human, pig, and sheep, where there are multiple transcripts of varying number, size, and relative abundance. No LH receptor message was detected in the brain or the uterus, as reported in other species. The predominant transcript identified in the mink CL, 2.4 kb, is large enough to encode the entire LH receptor protein, expected to have an open reading frame of approximately 2 kb. Buy Advair Diskus Online

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Luteotropic Hormone Receptors: DISCUSSION(4)

The putative transmembrane and cytoplasmic regions of the mink LH receptor cDNA were cloned and sequenced. This portion of the receptor gene had sequence homology of 84%, 85%, 90%, and 91% with the murine, rat, porcine, and human LH receptor gene sequences and 64-65% with the rat, human, ovine, and bovine FSH receptor cDNA. Of 22 potential phosphorylation sites (serine, threonine, tyrosine residues) in the intracellular region of rat LH receptor, 19 were conserved in the deduced amino acid sequence of the mink LH receptor. Cheap Diskus Advair

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Luteotropic Hormone Receptors: DISCUSSION(3)

DISCUSSION(3)

However, prolactin levels were correlated with prolactin receptor expression and were of sufficient magnitude to reactivate the CL, as indicated by the increase in progesterone secretion on March 27 and by the termination of embryonic diapause. The abundance both of prolactin receptor mRNA and of the number of prolactin binding sites in the ovary increased substantially after March 29, and highest levels were during implantation and early-postimplantation gestation, the time when progesterone production is maximal. This is in accordance with findings in the ovary of the pregnant mouse, where the long form of the prolactin receptor is most abundant during the luteal phase. The present result differs from findings in the rat, where the level of ovarian expression of both short and long forms of prolactin receptor mRNA was constant through most of gestation, declining only as parturition approached. proventil inhaler

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Luteotropic Hormone Receptors: DISCUSSION(2)

Northern analysis revealed that the mink prolactin receptor probe hybridized with multiple transcripts of 3.4, 4.4, and 10.5 kb. This pattern compares to rat long form with three transcripts of 2.5, 3.0, and 5.5 kb; the rabbit with three major transcripts of 2.7, 3.4, and 10.5 kb and one minor transcript of 6.2 kb; and the human with transcripts of 2.5, 3.0, and 7.3 kb. Tissue distribution analysis revealed a strong prolactin receptor hybridization signal in mink ovary and testes, and longer exposure of the blot indicated a signal in the uterus, adrenal, kidney, and liver. ventolin 100 mcg

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Luteotropic Hormone Receptors: DISCUSSION(1)

DISCUSSION(1)

A significant portion of the extracellular and all of the transmembrane domain of the mink prolactin receptor gene was cloned and sequenced. It had sequence homologies of 78%, 79%, 81%, 84%, and 86% with the rat, mouse, human, bovine, and rabbit prolactin receptor gene sequences, respectively. It also displayed 5354% homology with the rat, human, and rabbit growth hormone receptor gene from the same GH/ prolactin/cytokine receptor superfamily. buy birth control online

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Luteotropic Hormone Receptors: RESULTS(4)

The LH hybridization signal was less in whole ovaries after luteal activation and during postimplantation gestation. In whole ovaries, bromocriptine treatment not only that were killed on April 5, and all from April 10 and 15, had uterine swellings containing embryos. Calculated dates of implantation in the control group ranged from March 31 to April 8. Although blastocysts were present in bromocriptine-treated mink at each of the collection dates, none were expanded or showed any indication of resumption of development. flovent inhaler

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Luteotropic Hormone Receptors: RESULTS(3)

RESULTS(3)

Serum prolactin levels in the control group, composed of saline-treated and untreated mink, increased gradually through gestation from 14.15 ± 3.9 ng/ml during diapause (March 19) to 54.08 ± 7.6 ng/ml during postimplantation gestation (April 15, Fig. 1B). Delivery of 2 mg of bromocriptine per day by minipump reduced prolactin levels to below pretreatment values within 2 days of insertion of the pumps, and prolactin remained below control levels through the duration of the treatment (March 31, Fig. 1B, p < 0.05). Embryo implantation, as indicated by the occurrence of uterine swellings, was observed as early as March 31 in a few control animals. buy cipro

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Luteotropic Hormone Receptors: RESULTS(2)

Development of autoradiograms for periods of 2 or more weeks indicated the presence of two minor bands, one at > 6 kb and the other at 0.8 kb. Within the ovary, the probe bound to RNA from preovulatory follicles, CL, and the ovarian stroma, which contains small healthy and atretic follicles. buy ventolin inhalers

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Luteotropic Hormone Receptors: RESULTS(1)

RESULTS(1)

Mink Prolactin and LH Receptor cDNA

A 675-nt fragment of the mink prolactin receptor cDNA, corresponding to nucleotides 120-895 of the rat, human, murine, rabbit, and bovine sequences, was amplified, cloned, and sequenced (GenBank Accession #AF029294). The fragment included most of the putative extracellular and all of the transmembrane domains. It contained five cysteine residues conserved among all known prolactin receptor sequences and two potential ^-linked glycosylation sites. Northern analysis revealed that this probe hybridized with three principal transcripts, which were 3.4, 4.4, and 10.5 kb in size. buy yasmin online

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