Effect of Local Application of Ovarian Hormones on the Delay in Implantation in Lactating Rats

Yoshinaga, Koji

doi:10.1530/jrf.0.0020035

Cited by 45 publications

(26 citation statements)

References 9 publications

(11 reference statements)

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“…As described by Yoshinaga [1961], as soon as the central stimulation by suckling is less intensive, pro lactin secretion decreases and increasing re lease of FSH-LH enhances estrogen and pro gesterone production by the ovarian corpora lutea. Implantation supposedly occurs under the primary influence of estrogens [Yoshina ga, 1961;van der School et al, 1978].…”

Section: Discussionmentioning

confidence: 98%

Suckling-Induced Delay of Implantation and Increased Fecundity in Rats

Vorherr¹,

Vorherr²

1984

Gynecol Obstet Invest

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In rats fertilized during the 1 st or 2nd day postpartum (second consecutive pregnancy), suckling induces intrauterine blastocyst dormancy and delays implantation for 8–22 days. In spite of this relatively long time of blastocyst dormancy, associated with greatly reduced cellular metabolism, subsequent implantation and growth results in significantly larger litters (13.6 ± 0.62; x ± SE) than in primigravidas (10.4 ± 0.89) or in rats with a second-spaced pregnancy (11.2 ± 0.72). Enhanced fecundity in rats with second consecutive pregnancies may be attributed to increased ovarian blood supply of preceding gestation and/or to augmented pituitary FSH-LH secretion resulting in intensified ovarian gonadotropic stimulation for postpartum ovulation.

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Section: Discussionmentioning

confidence: 98%

Suckling-Induced Delay of Implantation and Increased Fecundity in Rats

Vorherr¹,

Vorherr²

1984

Gynecol Obstet Invest

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“…In the mouse (Yoshinaga & Adams, 1966) and rat (Canivenc & Laffargue, 1956;Yoshinaga, 1961;Psychoyos, 1973;Surani, 1975), however, these events require the presence of oestrogen as well as progesterone. It may be significant that the other two species for which an oestrogen requirement for implantation has been suggested, the roe deer (Aitken, 1974a(Aitken, , b, 1975 and fur seal (Daniel, 1974), also exhibit the phenomenon of delayed im¬ plantation.…”

Section: Discussionmentioning

confidence: 99%

Changes in the protein content of mouse uterine flushings during normal pregnancy and delayed implantation, and after ovariectomy and oestradiol administration

Aitken¹

1977

Reproduction

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Summary. The protein content of the mouse uterine lumen increased significantly (P < 0\m=.\001) on Day 4 of pregnancy, the day of implantation. This increase was associated with the presence of 14 serum and 22 non-serum proteins in the lumen; the major serum proteins were classed as high molecular weight slow \g=a\-globulins, while the dominant non-serum components consisted of slow and fast \g=a\-globulins, 6 prealbumins and a large quantity of proteinaceous material migrating near the origin of the gels.During experimental and lactational delayed implantation the protein levels were constantly low, transferrin, haemoglobin and albumin dominating the protein pattern. After administration of oestradiol-17\g=b\,however, a biphasic uterine response was detected, significant increases in luminal protein concentration being observed within 12 h and again at 40\p=n-\48h after injection. The first phase of this response involved an influx of serum and non-serum proteins into the uterine lumen, most proteins migrating as high molecular weight slow \g=a\-globulins. The second phase involved an increase in the intensity of many non-serum components, the major proteins having Ra values of 0\m=.\06,0\m=.\10and 0\m=.\32.The qualitative, but not the quantitative, aspects of this response to oestradiol were identical in the absence of blastocysts.

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“…The endometrial mucosa may serve as a barrier to implanta¬ tion; it is naturally disrupted in pseudopregnant animals over the deciduoma, and Kirby (1966) has shown that experimental removal of the endothelium in the mouse uterus can give rise to premature implantation of the blastocyst. The hormonal state of the host is known to influence the susceptibility of the uterus to bacterial infection in a number of species, probably due to an effect on the number and phagocytic activity of the leucocytes that reach the uterine lumen (Killingbeck 8c Lamming, 1963); but unfortunately, the rat does not seem to be one of the species that is subject to this effect (Lamming & Heap, 1960 (Cochrane & Meyer, 1957;Yoshinaga, 1961;Psychoyos, 1961), and im¬ plantation will occur about 24 hr later (Yasukawa & Meyer, 1966). Our results show that in the delayed implantation state, the tumour failed to develop (Group 3), whereas tumour growth occurred in the uteri of three out of seven rats given the 'implanting' injection of 0-2^g oestradiol-17ß (Group 5).…”

Section: Discussionmentioning

confidence: 99%