The superovulation of synchronous adult rats using follicle-stimulating hormone delivered by continuous infusion. Biol. Reprod. 44: 851–856. [Medline] [CrossRef

The estrous cycles of adult female rats were synchronized with an LHRH agonist on the morning of Day-4 (Day 0 = day of mating). On Day-2, animals received s.c. implants of continuous-infusion osmotic minipumps containing different doses of an FSH preparation (Foiltropin) in combination with hCG at various ratios of hCG: FSH or were given single injections of eCG in doses ranging from 15 LU to 60 LU. Rats infused with the optimal dose (3.4 U/day) of FSH ovulated 44.1 ± 5.4 oocytes/rat while rats treated with the most effective dose (60 LU) of eCG ovulated only 20.5 ± 4.3 oocytes/rat on the morning of Day 1. The inclusion of hCG in pumps at ratios from 0.188:1 to 0.75:1 (hCG:FSH) had no significant effect on ovulation rate. The importance of synchronization of estrus in successful superovulation was demonstrated by the finding that only 70 % of the unsynchronized animals ovulated (29.1 ± 4.8 oocytes/rat) whereas 95 % of the synchronized animals ovulated (51.0 ± 3.6 oocytes/rat). Oocyte viabilitles were assessed by determining fertilization rates and embryonic development in vivo following mating with fertile males. In rats superovulated by use of the FSH regimen, 92 % (39.0 ± 4.1) of the recovered embryos were I-cell zygotes on Day 1, 89 % (36.3 ± 5.6) were at the 2-cell embryo stage of development on Day 2, and 88 % (28.8 ± 2.2) were at the morula and blastocyst stages on Day 5 following mating on Day 0. The high ovulation rates and oocyte viability in rats receiving infusions of Foiltropin following estrus synchronization offer a reliable method for superovulation of adult rats