In vitro and in vivo evidence on the site of neutralization of equine chorionic gonadotrophin (eCG) by an eCG antiserum.
Abstract: This study was designed to determine whether the major site of eCG neutralization by an antiserum to the hormone is at the peripheral or ovarian level. Hamsters hypophysectomized at oestrus were injected s.c. with 25 iu eCG. Three days later, preovulatory follicles were dissected and cultured for 5 h and the medium was changed every hour. At the end of the first hour of incubation, oestradiol and androstenedione accumulation was high, with a sharp drop over the next 4 h, whereas progesterone concentrations did not change over the entire period. Addition of eCG antiserum to the incubated follicles did not affect steroidogenesis. Addition of 1.0 iu eCG in the second hour or every hour sustained oestradiol production at supraphysiological amounts. However, addition of eCG plus eCG antiserum every hour eliminated the stimulatory effects of eCG on oestradiol production. In another experiment, hamsters injected with eCG were treated 3 days later by i.p. injection of eCG antiserum and groups of animals were killed over the next 8 h. Serum samples before and after injecting eCG antiserum were incubated overnight with a goat anti-rabbit immunoglobulin to separate free, unbound eCG from bound eCG. At time zero (before injecting the antiserum) free eCG was increased, but within 1 h after eCG antiserum there was an eightfold decrease of the hormone, and these concentrations were maintained over the next 7 h. The fall in unbound eCG in vivo coincided with the decay in serum oestradiol and androstenedione.(ABSTRACT TRUNCATED AT 250 WORDS)
Publication Date: 1995-07-01 PubMed ID: 7473414DOI: 10.1530/jrf.0.1040237Google Scholar: Lookup
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- Journal Article
- Research Support
- U.S. Gov't
- P.H.S.
Summary
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This research investigated the main site where the hormone equine chorionic gonadotrophin (eCG) is neutralized by an antiserum, and found it occurs at the peripheral level, not the ovarian level. The study used hamsters and various hormone concentrations to observe the effects of the antiserum.
Research Methodology
- The researchers used hamsters that had been hypophysectomized at oestrus for the study. The hamsters were injected subcutaneously with 25 international units of eCG. After three days, the preovulatory follicles were dissected and cultured for five hours, changing the medium every hour.
- To observe the effects of the eCG antiserum on steroidogenesis (the process of steroid production), the follicles were incubated with the antiserum. The levels of oestradiol, androstenedione, and progesterone were measured several times in the course of this experiment.
- A second experiment was conducted where the hamsters were injected with eCG and then treated with the antiserum. The hamsters were then examined at several intervals over the next 8 hours.
Results and Findings
- The research found that the application of eCG antiserum did not affect steroidogenesis, meaning that the process of steroid production was not influenced by the addition of the antiserum.
- Programmed addition of eCG was able to maintain oestradiol production at supersized amounts by the hamsters. When eCG and eCG antiserum were added together, the stimulatory effects of eCG on oestradiol production was eliminated.
- In the follow-up experiment, the researchers found that unbound eCG levels experienced a sharp decrease within an hour of antiserum injection. This decrease maintained over the next 7 hours, which coincides with decreases in serum oestradiol and androstenedione.
- Overall, these findings suggest that the major site of eCG neutralization by its antiserum is at the peripheral level rather than at the ovarian.
Cite This Article
APA
Wang X, Kole AR, Greenwald GS.
(1995).
In vitro and in vivo evidence on the site of neutralization of equine chorionic gonadotrophin (eCG) by an eCG antiserum.
J Reprod Fertil, 104(2), 237-241.
https://doi.org/10.1530/jrf.0.1040237 Publication
Researcher Affiliations
- Ligand Pharmaceuticals, La Jolla, CA 92037, USA.
MeSH Terms
- Androstenedione / metabolism
- Animals
- Cricetinae
- Culture Techniques
- Estradiol / metabolism
- Female
- Gonadotropins, Equine / blood
- Gonadotropins, Equine / immunology
- Gonadotropins, Equine / metabolism
- Half-Life
- Hypophysectomy
- Immune Sera / immunology
- Mesocricetus
- Ovarian Follicle / metabolism
- Time Factors
Grant Funding
- HD00596(31) / NICHD NIH HHS
- HD0252 / NICHD NIH HHS
Citations
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