A Corpus Luteum-Stimulating Substance in the Rat Placenta.

Astwood, E. B.; Greep, Roy O.

doi:10.3181/00379727-38-9991

Cited by 132 publications

(34 citation statements)

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“…Uterine preparation for embryo implantation is dependent on continued estrogen and progesterone secretion by the corpus luteum of the ovary, which is supported by the pituitary in rodents during the first half of pregnancy (Astwood and Creep 1938). Recently, prolactin has been shown to stimulate progesterone synthesis by dispersed ovarian cells from midpregnant mice (Galosy and Talamantes 1995), demonstrating that lactogenic hormones can stimulate directly ovarian progesterone secretion.…”

Section: Embryo Implantation and Pseudopregnancymentioning

confidence: 99%

Null mutation of the prolactin receptor gene produces multiple reproductive defects in the mouse.

Ormandy¹,

Camus²,

Barra³

et al. 1997

Genes Dev.

719

429

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Mice carrying a germ-line null mutation of the prolactin receptor gene have been produced by gene targeting in embryonic stem cells. Heterozygous females showed almost complete failure of lactation attributable to greatly reduced mammary gland development after their first, but not subsequent, pregnancies. Homozygous females were sterile owing to a complete failure of embryonic implantation. Moreover, they presented multiple reproductive abnormalities, including irregular cycles, reduced fertilization rates, defective preimplantation embryonic development, and lack of pseudopregnancy. Half of the homozygous males were infertile or showed reduced fertility. This work establishes the prolactin receptor as a key regulator of mammalian reproduction, and provides the first total ablation model to further study the role of the prolactin receptor and its ligands.

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Section: Embryo Implantation and Pseudopregnancymentioning

confidence: 99%

Null mutation of the prolactin receptor gene produces multiple reproductive defects in the mouse.

Ormandy¹,

Camus²,

Barra³

et al. 1997

Genes Dev.

719

429

View full text Add to dashboard Cite

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“…However, Astwood & Greep (1938) provided evidence for an extra-pituitary source of luteotrophin in the pregnant rat which was later referred to as "chorionic gonadotrophin" by Astwood (1953). More recently, extracts or expiants from placentae of hamster, mouse, rat and sheep have behaved in a number of biological and non-biological assays in a manner which suggests a similarity between ovine, rodent and human CG (Linkie & Niswender, 1973;Okker-Reitsma, 1978;Haour, Tell & Sanchez, 1976; Wide & Hobson, 1978;Wide & Wide, 1979;Lacroix & Martal, 1979;Okker-Reitsma & Wilson, 1980; Wide, Hobson & Wide, 1980).…”

Section: Introductionmentioning

confidence: 99%

Gonadotrophic activity of the guinea-pig placenta during pregnancy

Humphreys¹,

Hobson²,

Wide³

1982

Reproduction

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Summary. A gonadotrophic substance was extracted from placentae and subplacentae of guinea-pigs. Biological and immunological assays of these tissues obtained on Days 10\p=n-\63of pregnancy showed the highest mean concentration of the gonadotrophin on Day 18. Extracts chromatographed on Sephadex G200 had components active in the radioimmunoassay system for hCG, hCG-alpha and hCG-beta subunits. The elution profiles of these extracts were similar to those obtained with human term placentae and purified hCG and its subunits. The guinea-pig placental extracts also cross-reacted with an antiserum to the beta subunit of ovine LH, as did hCG. The biological activity of placental and subplacental extracts and of the hCG standard was neutralized by an anti-hCG serum. There is a strong similarity between hCG and the substance extracted from guinea-pig placentae which may therefore have a luteotrophic function similar to that of hCG.

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“…This was possibly due to a luteotrophic effect of placental lactogen (Astwood and Greep, 1938;Averill et al, 1950, Ray et al, 1955, which seemed to increase gradually in secretion before day 12 of preg.. This difference in the size of the corpus luteum supported the findings that the total progestin output from the ovary during psp.…”

Section: Resultsmentioning

confidence: 79%

“…However, after the 12th day pregnancy was maintained, evidently because the placenta secreted a luteotrophic hormone in sufficient amount by this time (Alloiteau, 1957 ;Rothchild 1960 ;Astwood and Greep, 1938 ;Pencharz and Long, 1933). Presence of prolactin-like hormone in the rat placenta which had a luteotrophic effect has been reported (Astwood and Greep, 1938;Averil et al, 1950, Ray et al, 1955. The significant difference between the average size of the corpus luteum per rat on days 9-10 of preg.…”

Section: Resultsmentioning

confidence: 99%