Concentrations of nitric oxide in equine preovulatory follicles before and after administration of human chorionic gonadotropin.
Abstract: In the present study, follicular fluids of estrous mares treated with saline solution (Control) or nitric oxide synthase (NOS) inhibitors were analyzed for nitric oxide (NO), estradiol-17beta (E2) and progesterone (P4) concentrations before and 36h after administration of human chorionic gonadotropin (hCG). Follicular fluids obtained before (0h) hCG administration from control mares had lower concentrations of NO than those obtained 36h after administration of hCG (58.3+/-17.8 micromol versus 340.4+/-57.7 micromol; P<0.05). A similar pattern was also noted for intrafollicular P4 in control mares, which had lower concentrations of intrafollicular P4 before hCG than 36h post-hCG administration (P<0.05). As expected, E2 concentrations of control follicles sampled before hCG administration were higher than those sampled 36h post-hCG administration (P0.10). In addition, mares treated with NOS inhibitors had lower intrafollicular concentrations of NO and P4 than control mares, both before and after hCG administration (P<0.05). Increased intrafollicular concentrations of NO in control, hCG-stimulated mares provide evidence for the presence of an NO-generating system in the equine preovulatory follicle that is likely upregulated following administration of hCG.
Publication Date: 2003-08-26 PubMed ID: 12935860DOI: 10.1016/s0093-691x(03)00096-7Google Scholar: Lookup
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- Journal Article
- Research Support
- Non-U.S. Gov't
Summary
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This research paper investigates the concentrations of nitric oxide in the preovulatory follicles of mares before and after the administration of human chorionic gonadotropin (hCG). The study revealed that nitric oxide levels and progesterone concentrations increased while estradiol levels decreased following the administration of hCG. This provides evidence of an upregulated nitric oxide-generating system in the equine preovulatory follicle after hCG administration.
Investigation on Nitric Oxide Concentrations
- The researchers analyzed the follicular fluids of estrous mares. They used a control group treated with a saline solution and another group treated with nitric oxide synthase (NOS) inhibitors.
- The fluids were examined for nitric oxide (NO), estradiol-17beta (E2) and progesterone (P4) concentrations before and 36 hours after the administration of hCG.
- The results showed that control mares had lower nitric oxide concentrations in follicular fluids obtained before hCG administration than those obtained 36 hours after. This increase in nitric oxide signals that an NO-generating system in the equine preovulatory follicle is possibly upregulated with the administration of hCG.
Observations on Estradiol and Progesterone Levels
- Similar to nitric oxide, progesterone levels increased in control mares following the administration of hCG.
- On the contrary, estradiol levels of control follicles sampled before hCG administration were higher than those sampled 36 hours post-hCG administration.
Effects of Nitric Oxide Synthase (NOS) Inhibitors
- The study also analyzed the effects of NOS inhibitors, N(omega)-nitro-L-arginine methyl ester (L-NAME) and aminoguanidine (AG) on nitric oxide and progesterone concentrations, as well as on estradiol levels.
- It was found that mares treated with NOS inhibitors had lower intrafollicular concentrations of nitric oxide and progesterone, both before and after hCG administration.
- In addition, unlike control mares, estradiol concentrations in follicles of mares treated with NOS inhibitors did not decrease after hCG administration.
Cite This Article
APA
Pinto CR, Paccamonti DL, Eilts BE, Venugopal CS, Short CR, Gentry LR, Thompson DL, Godke RA.
(2003).
Concentrations of nitric oxide in equine preovulatory follicles before and after administration of human chorionic gonadotropin.
Theriogenology, 60(5), 819-827.
https://doi.org/10.1016/s0093-691x(03)00096-7 Publication
Researcher Affiliations
- Equine Health Studies Program, Department of Comparative Biomedical Sciences, Louisiana State University and Agricultural Center, Baton Rouge, LA 70803, USA. carlos_pinto@ncsu.edu
MeSH Terms
- Animals
- Chorionic Gonadotropin / administration & dosage
- Enzyme Inhibitors / pharmacology
- Estradiol / analysis
- Female
- Follicular Fluid / chemistry
- Guanidines / pharmacology
- Horses / metabolism
- Kinetics
- NG-Nitroarginine Methyl Ester / pharmacology
- Nitric Oxide / analysis
- Nitric Oxide Synthase / antagonists & inhibitors
- Ovulation
- Progesterone / analysis
Citations
This article has been cited 2 times.- Da Broi MG, Giorgi VSI, Wang F, Keefe DL, Albertini D, Navarro PA. Influence of follicular fluid and cumulus cells on oocyte quality: clinical implications. J Assist Reprod Genet 2018 May;35(5):735-751.
- Khan FA, Das GK. Follicular characteristics and intrafollicular concentrations of nitric oxide and ascorbic acid during ovarian acyclicity in water buffalo (Bubalus bubalis). Trop Anim Health Prod 2012 Jan;44(1):125-31.
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