Ovulation in the Rabbit: The Time of Follicular Rupture and Expulsion of the Eggs, in Relation to Injection of Luteinizing Hormone

Abstract

Fifty-five mature oestrous does were injected intravenously with luteinizing hormone (LH) and subsequently killed between 9 hr. 52 min. and 14 hr. 30 min. after injection. At autopsy the number of freshly ruptured follicles was counted and was expressed as a percentage of the total number of follicles (ruptured and unruptured) counted, that had undergone pre-ovulatory swelling. This method of calculating 'percentage ovulation' gave results which agreed very closely with previously reported data. The calculation showed no ovulation by 10 hr., 50% ovulation between 10\ m=1/ 2\ and 103/4 hr., and 100% ovulation by 14 hr. after the injection of LH.In thirty-nine out of these fifty-five does a special study was carried out to determine in what position (in the ruptured follicle, on the surface of the ovary or in the Fallopian tube) the eggs from the ruptured follicles were recovered in relation to the time elapsing after LH injection. Between 10\ m=1/ 2\ and 11\ m=1/ 2\ hr. after injection about 17% of the eggs were found either still inside the ruptured follicle, or within the cumulus oophorus protruding from the follicle or adhering to the ovarian surface. However, at 11\m=1/2\-13 hr. after injection only 3\m=.\6-5\m=.\9% were still in the follicle or on the ovarian surface. From 13 hr. after LH injection all the eggs recovered were found in the Fallopian tube. These results suggest that not all the eggs are ejected from the follicle at the time of rupture, and that some appreciable time may elapse between follicular rupture and entry of eggs into the tube.

The Microvasculature of the Ovary. A Review by SEM of Vascular Corrosion Casts.

“…Rabbits were then sacrificed 10-12 hours, 1-2-7-14-17 days after hCG injection. Ovulation was assumed to occur about 10-12 hours after hCG administration [52]. Reflex ovulation was induced in other rabbits by mating.…”

Ovarian Response and Cleavage Rate of Ova in Control and FSH-Primed Rabbits Receiving Varying Levels of Luteinizing Hormone

“…Ovulation or superovulation in rabbits has been induced by a variety of pre¬ parations containing gonadotrophins (Pincus, 1940;Parkes, 1943;Warwick, Murphree, Casida & Meyer, 1943;Adams, 1956;Beatty, 1958;Hafez, 1961;Harper, 1963;Kennelly & Foote, 1965). Many of these vary considerably in potency and a wide range of dosages has been employed.…”

“…A second objective was to compare cleavage stages in fertilized ova collected from FSH-primed and control rabbits at corresponding intervals after lh injection, since the work of Kennelly & Foote (1965) suggested that ovulation may be somewhat prolonged in superovulated animals when compared with those ovulated normally (Harper, 1963 Immediately after the administration of lh does were inseminated with 0T ml of high quality semen collected from fertile bucks. The semen samples were divided and used randomly across all treatment groups.…”

Cell Numbers in Rabbit Pre-implantation Blastocysts

“…hours later (Harper 1963). All does were caged separately for at least four weeks before mating to eliminate pseudopregnant animals.…”