Delayed Implantation Caused by Administration of Sheep Immunogamma Globulin against LHRH in the Rat

Akira Arimura, Nozomu Nishi, Andrew V. Schally

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18 Scopus citations


The effect of the administration of sheep anti LHRH gamma globulin (anti LHRH G) on implantation of fertilized ova was investigated in rats. Daily injections of 1 ml of anti LHRH G from Days 1 through 7 of pregnancy uniformly inhibited implantation of fertilized ova on Day 8, but viable sites, though considerably smaller in size than in control rats, became distinguishable on Day 14 in most rats. In some of these rats resorption of fetuses occurred, and others delivered 7-8 days after term. When the rats were given anti LHRH G from Days 3 through 5, the implantation was delayed by 5 days, but the gestation was not terminated. A single injection of 1 ml of anti LHRH G on Day 4 inhibited implantation on Day 8, but injection on Day 3 or 5 did not. The delayed implantation by anti LHRH G injected on Day 4 was nullified by concomitant administration of 2 sc injections of 1 μg of LHRH, or a single dose of 1 μg of estradiol. The data indicate that the hypothalamic LHRH is essential on Day 4 of pregnancy for timely implantation of fertilized ova, probably by maintaining LH and, consequently, estrogen secretion.

Original languageEnglish (US)
Pages (from-to)71-75
Number of pages5
JournalProceedings of the Society for Experimental Biology and Medicine
Issue number1
StatePublished - May 1976
Externally publishedYes

ASJC Scopus subject areas

  • Biochemistry, Genetics and Molecular Biology(all)


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