The superovulation of synchronous adult rats using follicle-stimulating hormone delivered by continuous infusion.
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 (Folltropin) in combination with hCG at various ratios of hCG:FSH or were given single injections of eCG in doses ranging from 15 IU to 60 IU. 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 IU) 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 viabilities 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 1-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 Folltropin following estrus synchronization offer a reliable method for superovulation of adult rats.
Hamilton
G S
GS
Department of Physiology and Obstetrics and Gynaecology, University of Western Ontario, London, Canada.
Armstrong
D T
DT
D000818:Animals; D006063:Chorionic Gonadotropin / Q000008:administration & dosage; D004971:Estrus / Q000187:drug effects; D005260:Female; D005640:Follicle Stimulating Hormone / Q000008:administration & dosage*; D007260:Infusion Pumps; D009865:Oocytes / Q000187:drug effects; D010053:Ovary / Q000187:drug effects; D051381:Rats; D011919:Rats, Inbred Strains; D013480:Superovulation / Q000187:drug effects*
D006063:Chorionic Gonadotropin; D005640:Follicle Stimulating Hormone