JOURNAL ARTICLE

Inhibitors of nitric oxide synthase influence oocyte maturation in rats

A Jablonka-Shariff, R Basuray, L M Olson
Journal of the Society for Gynecologic Investigation 1999, 6 (2): 95-101
10205780

OBJECTIVE: To examine the effect of inhibiting nitric oxide synthase (NOS) on the number of ovulated oocytes and on oocyte meiotic maturation.

METHODS: Female Sprague-Dawley rats (25 days old) were superovulated with a subcutaneous injection of 10 U pregnant mare's serum gonadotropin, followed 52 hours later by a subcutaneous injection of 10 U human chorionic gonadotropin (hCG). Three hours before and 3 hours after hCG injection, the rats were treated orally with the vehicle (0.5% methylcellulose) as the control or with either of two NOS inhibitors, N omega-nitro-L-arginine methyl ester (L-NAME) and L-N6-(1-iminoethyl)-lysine (L-NIL). The rats were killed 20 hours after hCG injection, and oocytes present in the oviduct were flushed, counted, and classified for stages of meiosis. In addition, ovarian oocytes (12 hours post-hCG) and ovulated oocytes were treated with an immunofluorescent stain for the presence of endothelial NOS (eNOS).

RESULTS: Strong positive staining for eNOS was observed in the cytoplasm of ovarian and ovulated oocytes. Control rats ovulated an average 43.0 +/- 4.1 oocytes each, which was lowered with either L-NAME or L-NIL (23.8 +/- 4.3 and 23.5 +/- 4.0 oocytes per rat, respectively; P < .002). We observed that significantly fewer ovulated oocytes obtained from rats treated with NOS inhibitors were at metaphase II (P < .006), the normal stage of meiosis for unfertilized oocytes, and a significantly greater percentage of oocytes displayed atypical morphology as compared with control oocytes (P < .0001).

CONCLUSION: Ovarian nitric oxide synthesis is required for maximal ovulation, and a lack of nitric oxide during the periovulatory period results in severe defects in oocyte maturation.

Full Text Links

Find Full Text Links for this Article

Discussion

You are not logged in. Sign Up or Log In to join the discussion.

Trending Papers

Remove bar
Read by QxMD icon Read
10205780
×

Save your favorite articles in one place with a free QxMD account.

×

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"