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At least 109 records · Page 6Linked to original sources
PubMed1997

Effects of equine chorionic gonadotropin, human chorionic gonadotropin, and laparoscopic artificial insemination on embryo, endocrine, and luteal characteristics in the domestic cat.

The effects of gonadotropin treatment and laparoscopic artificial insemination (AI) on embryo quality, serum progesterone and estradiol concentrations, and luteal progesterone content were examined in the domestic cat. These data were compared to similar historical data reported for naturally estrual, mated queens. All queens in this study (n = 32) were treated with eCG followed by 1) natural breeding (eCG-NB), 2) NB and hCG (eCG-NB-hCG), 3) NB and a sham AI procedure (eCG-NB-sham AI), or 4) hCG and actual AI (eCG-hCG-AI). Queens ovulating in response to treatment were ovariohysterectomized, and oviducts and uteri were flushed to collect embryos. Ovarian structures were recorded, corpora lutea (CL) were excised and evaluated for progesterone content, and serum was analyzed for estradiol-17beta and progesterone. Follicle and CL numbers ranged from 0 to 28 and 2 to 42 per cat, respectively, and treatment means did not differ (p > or = 0.05) among groups. Embryos were recovered from oviducts and uterine horns in all treatment groups, and recovery ranged from 60-96%. Mean embryo number per queen ranged from 8.2 +/- 2.6 to 23.2 +/- 3.8 and did not differ (p > or = 0.05) among groups. However, the proportions of unfertilized oocytes were greater (p < 0.05) for groups treated with hCG and/or artificially inseminated, and the proportion of blastocysts produced (31 of 107, 29.0%) was lower (p < 0.05) in the eCG-hCG-AI group than for any other treatment (range, 59 of 116 [50.9%] to 67 of 116 [57.8%]). Not all queens in each group produced good-quality embryos (eCG-NB, 5 of 5; eCG-NB-hCG, 5 of 8; eCG-NB-sham AI, 2 of 5; and eCG-hCG-AI, 3 of 6). Serum progesterone and estradiol-17beta, and total luteal progesterone per ovary did not differ (p > or = 0.05) among treatments. Compared to historical controls (naturally estrual, mated queens), eCG-NB queens produced > 4 times as many good-quality embryos and blastocysts. Similarly, eCG-hCG-AI-treated queens produced > 4 times the number of oocytes and embryos, although a high proportion of these were poor quality and did not develop to blastocysts. Together, these results indicate that queens treated with eCG are capable of consistently producing many good-quality embryos, at least half of which develop to blastocysts in culture. These data support the use of eCG in felids and suggest that other factors are responsible for reduced pregnancy success and small litter sizes following assisted reproduction.

Animals↗
PubMed1999

Autoradiographic analysis of follicle-stimulating hormone and human chorionic gonadotropin receptors in the ovary of immature rats treated with equine chorionic gonadotropin.

The gonadotropin-primed immature rat has become the most common model for the study of follicular development and ovulation. In this study, prepubertal female rats, 23 and 24 days old, were injected s. c. with 5 IU eCG, and ovaries were collected for topical autoradiography of FSH and hCG receptors at 48 or 24 h post-eCG, respectively (i.e., Day 25). In a baseline group, on Day 25 (before eCG), even the smallest preantral follicles with 1 layer of granulosa cells (GCs; primary follicles) possessed FSH receptors, but hCG receptors were found only on the theca of follicles with 2 or more layers of GCs. Human CG receptors were especially prominent in the interstitium that intimately surrounds preantral follicles without any distinction between theca and interstitial cells. There was a discrete theca surrounding antral follicles. Occasionally antral follicles had hCG receptors in the interstitium, but the adjacent theca was negative, suggesting that these follicles might be destined for atresia. By 24 h post-eCG, a now-discrete theca layer with hCG receptors surrounded all preantral follicles except for the primary follicles, which never responded to eCG. The interstitium was hypertrophied and epithelioid, as was the theca surrounding nonatretic preantral and antral follicles. Increased mitotic activity characterized the growing preantral follicle, and for the first time, FSH binding in GCs of antral follicles was greater than in the preantral population. By 48 h post-eCG, the primary follicles were still unresponsive to eCG. FSH receptors were even more pronounced in the GCs of large antral follicles, although hCG receptors were present in the GCs of only one third of the antral follicles, reflecting the small dose of eCG administered. By 48 h post-eCG, receptors in the interstitium were barely detectable. Using this model, the following study considers the functional in vitro changes in steroidogenesis in follicles from the smallest preantral follicles to the largest antral follicles.

Animals↗
PubMed1995

[Modification of chorionic carcinoma cells by immunomodulators. Cytokines and chorionic carcinoma cells].

OBJECTIVES: The role of inflammatory cytokines on regulation of hCG biosynthesis was studied. METHODS: JAR choriocarcinoma cells were cultured and treated with interleukin-1 (IL-1), IL-3. IL-4, stem cell factor (SCF), tumor necrosis factor (TNF), and granulocyte or granulocyte-macrophage-colony stimulating factor. hCG concentration was determined by immunoradiometric methods and cell number was enumerated by means of an electronic particle counter. RESULTS: Il-1 and TNF increased biosynthesis of holo-hCG as well as the free alpha- and free beta-subunit and the beta-core protein. Proliferation was not affected by any cytokine tested. CONCLUSION: Inflammatory cytokines are able to increase the biosynthesis of hCG.

Cell Division↗
PubMed1979

Ovarian responses of pregnant mare serum gonadotropin- and human chorionic gondotropin-primed rats: desensitizing, luteolytic, and ovulatory effects of a single dose of human chorionic gonadotropin.

We conducted a study to determine the morphological appearance and functional responsiveness of ovarian tissues after administration of hCG to 28-day-old rats primed 65 h earlier with PMS gonadotropin (PMSG) and after administration of a second dose of hCG 5 days later, i.e. to 33-day-old rats containing heavily luteinized ovaries. Sixty-five hours after the administration of 50 IU PMSG sc to 25-day-old rats, ovaries already contained an abundance of luteinized follicles and an adenylyl cyclase (AC) system that was responsive to LH, epinephrine, and NaF. The administration of 50 IU hCG sc at this time initially resulted in a loss of LH-responsive ovarian AC. Within 4 days of the hCG injection, the ovaries of the now 32-day-old rats were heavily luteinized, and ovarian AC was highly responsive to LH, epinephrine, and NaF. The administration of a single sc dose of 200 IU hCG to 33-day-old PMSC- and hCG-primed rats with luteinized ovaries resulted in a rapid desensitization of the ovarian AC to LH and a drop in serum progesterone levels, During the subsequent 7 days, serum progesterone levels continued to decline, while total ovarian AC reacquired responsiveness to LH by days 4--5 after the densensitizing dose of hCG. Dissection of ovarian components revealed, however, that the AC system of the corpora lutea originally present at the time of the second hCG injection remained permanently refractory to LH and that the AC in corpora lutea newly formed from freshly ovulated follicles exhibited a significant responsiveness to LH, epinephrine, and NaF. However, these new corpora lutea were not fully active, since serum progesterone never rose. Subcutaneous administration of 50 IU hCG to 33-day-old PMSG- and hCG-primed rats also promoted a rapid loss of AC responsiveness to LH. This lower concentration of hCG was not sufficient to promote follicular development or ovulation, and the ovarian AC remained refractory to LH for at least 7 days. Intravenous administration of 75 IU hCG to 33-day-old PMSG- and hCG-primed rats similarly promoted a rapid and permanent loss of luteal AC responsiveness to LH; again, follicles did not mature to a preovulatory state and, in fact, appeared to undergo atresia rather than ovulation. These results indicate that in heavily luteinized ovaries 1) hCG promotes desensitization of rat luteal AC to LH, 2) Desensitization of AC to LH stimulation in corpora lutea is permanent and irreversible, and 3) only under conditions where follicles mature and ovulate and new corpora lutea are formed does total ovarian AC reacqure responsiveness during the subsequent week.

Adenylyl Cyclases↗
PubMed1979

Human chorionic gonadotropin in BeWo trophoblastic cells after 12 years in continuous culture: retention of intact human chorionic gonadotropin secretion in mechanically versus enzyme-dispersed cells.

Gel filtration and radioimmunological studies were used to demonstrate that BeWo malignant trophoblastic cells, subcultured for more than 12 yr as roller tube colonies using dissection by scalpel, retained the ability to secrete large quantities of intact hCG. By contrast, BeWo cells that had been subcultured weekly for 12 hr using proteolytic enzyme dispersion lost their ability to secrete intact hCG. Rather, a large form of hCG-alpha was the major secretory product, along with lesser amounts of heterogeneous low molecular weight forms of hCG-beta. The gradual loss of hormone secretory ability and fidelity of hormone product by cells in continuous culture is a well known phenomenon. Our results suggest that the habitual use of trypsin-EDTA to subculture cells may accelerate this process.

Cell Line↗