Evidence for Early Ovarian Recognition of Blastocysts in Rabbits

Fuchs, Anna‐Riitta; Beling, Carl G.

doi:10.1210/endo-95-4-1054

Cited by 67 publications

(21 citation statements)

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“…Previous reports indicate that rabbit blastocysts at 5-6 daysp.c. contain 150-250pgprogesterone(Lutwak-Mann, 1971 ;Fuchs & Beling, 1974). These amounts are higher than those reported in Table 1 and may be due either to variation in size of the preimplantation blastocysts or to the use of different assay procedures (competitive protein binding assay or radioimmunoassay).…”

Section: Discussionmentioning

confidence: 94%

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Accumulation of steroids in rabbit preimplantation blastocysts

Borland¹,

Erickson²,

Ducibella³

1977

Reproduction

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Summary. The concentrations of progesterone, androstenedione, testosterone, oestrone and oestradiol were measured by radioimmunoassay in blastocysts and uterine fluid flushings collected from rabbits 110 to 159 h post coitum (p.c.). None of the blastocysts or uterine flushings contained detectable levels of androstenedione, testosterone or oestrone. All uterine flushings contained large amounts of progesterone and some of the flushings also contained oestradiol.A small amount of progesterone (\ m=~\ 7\ m=. \ 5pg/blastocyst) was first detectable in some blastocysts at 135 h p.c.; progesterone levels/blastocyst then increased progressively, reaching levels of about 122\p=n-\158 pg/blastocyst at 159 h p.c. Micropuncture of blastocysts at 159 h p.c. indicated that \ m=ge\ 90 % of the progesterone in the embryo was in the blastocoelic fluid. Blastocysts from rabbit uterine horns containing oestradiol also contained oestradiol but those in which oestradiol was detected were never observed in uteri lacking the hormone. It is inferred that rabbit blastocysts accumulate both progesterone and oestradiol from uterine fluid.

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Section: Discussionmentioning

confidence: 94%

“…(Seamark & Lutwak-Mann, 1972;Fuchs & Beling, 1974). Seamark & Lutwak-Mann (1972) suggested that the presence of large amounts of progesterone in uterine fluid could indicate that progesterone is not synthesized by the blastocyst but rather is transferred to them via uterine secretions.…”

Section: Introductionmentioning

confidence: 99%

Accumulation of steroids in rabbit preimplantation blastocysts

Borland¹,

Erickson²,

Ducibella³

1977

Reproduction

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“…The observation of Fuchs & Beling (1974) that blood progestagen concentrations in the pregnant rabbit are significantly higher than those in the pseudopregnant rabbit after only 5 days of gestation indicates either that the conceptus may be secreting a substance which stimulates the corpus luteum (CL) to secrete progesterone or that the blastocyst itself could be secreting the progestagen. Im¬ plantation in the rabbit occurs 7 days post coitum and so the stimulus for such secretion must come from the preimplantation blastocyst.…”

Section: Introductionmentioning

confidence: 99%

A stimulatory effect of the fluid from preimplantation rabbit blastocysts upon luteinization of monkey granulosa cell cultures

Cp¹,

Sl²,

Cn³

et al. 1978

Reproduction

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Summary. Blastocyst fluid was aspirated from Day 6\ m=1/ 2\ \ p=n-\ 7rabbit blastocysts and was added to cultures of granulosa cells obtained from preovulatory follicles of untreated rhesus monkeys or from follicles of monkeys treated with PMSG. The stimulation of progesterone secretion was measured and equated with that produced by hCG. The hCG-like activity was also measured in a radioreceptor assay using 125I-labelled hCG and porcine granulosa cells.In 8 out of 10 experiments with cultured cells from untreated monkeys, addition of 20% blastocyst fluid from Days 6\p=n-\9of culture stimulated progesterone secretion by 2\ x =r eq-\ to 6-fold. Similar findings were obtained in 5 experiments with cultures from PMSG\x=req-\ treated monkeys except that the blastocyst fluid was added from Days 0 to 6 of culture. The granulosa cells in such cultures underwent morphological luteinization. Compared to a standard of purified hCG the blastocyst fluid contained about 0\m=.\76\p=n-\2\m=.\5 ng hCG\x=req-\ like activity/ml which was non-dialysable. The radioreceptor assay indicated the presence of 0\ m=. \ 5\ p=n-\ 2\ m=. \ 5 ng hCG-like material/ml.

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“…However, the data reported by various workers on this subject are not univocal, and are often difficult to correlate because they are the result of investiga- Further biochemical investigations have evidenced the presence of progesterone, oestrogens and other steroids in the blastocyst and/or in the blastocele fluid of the rabbit (Seamark and Lutwak-Mann, 1972 ; Eik-Nes et al, cit. by Lutwak-Mann, 1971 ;Fuchs and Beling, 1974 ;Borland et al, 1977 ;Fujimoto and Sundaram, 1978 ;Singh and Booth, 1978) and of the pig (Perry et al, 1973 ;Heap et al, 1975).On the other hand the uterine fluid contains large amounts of progesterone (Seamark and Lutwak-Mann, 1972 ;Fuchs and Beling, 1974 ;Cowman et al, 1976 ;Borland et at., 1977 ;Fowler et al, 1977) and oestrogens Borland et al, 1977). This has induced many workers to assume that the hormones found in the preimplantation blastocyst have an uterine origin (Seamark and LutwakMann, 1972 ;Borland et al, 1977 ;Fujimoto and Sundaram, 1978 ;Singh and Booth, 1978).…”

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confidence: 99%

mentioning

confidence: 99%

Histochemical demonstration of steroidogenic activity in preimplantation bovine embryos

Lauria¹,

Oliva²,

Aureli³

et al. 1979

Ann. Biol. anim. Bioch. Biophys.

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Summary. 3p-HSD activity has been demonstrated histochemically in bovine Day [6][7][8] late-morulae and early blastocysts recovered non-surgically from 12 superovulated Friesian heifers. In some embryos grown in vitro from late-morula to enlarged blastocyst in Eagle's enriched medium, this key enzyme in steroidogenesis was clearly demonstrable during all the period of their survival in culture (96 hrs).These findings are in favour of the capacity of the bovine embryo to synthesize steroids at least in some stages of early development.In recent years there has been an increasing interest in embryonic endocrinology in the initial stages of development, i.e. bofore implantation on the uterine wall. One of the most important factors justifying such an interest is the need to know when and by which processes the fertilized ovum signals its presence to the maternal organism in order to establish the pregnancy. The rapid diffusion of embryo transfer methodology both in laboratory and in farm animals has further stimulated investigations on this and on other important metabolic functions of the early embryo.At present, numerous findings prove the presence in the preimplantation blastocyst of steroid hormones and of enzymes involved in their metabolism and interconversion. However, the data reported by various workers on this subject are not univocal, and are often difficult to correlate because they are the result of investiga- Further biochemical investigations have evidenced the presence of progesterone, oestrogens and other steroids in the blastocyst and/or in the blastocele fluid of the rabbit (Seamark and Lutwak-Mann, 1972 ; Eik-Nes et al., cit. by Lutwak-Mann, 1971 ;Fuchs and Beling, 1974 ;Borland et al., 1977 ;Fujimoto and Sundaram, 1978 ;Singh and Booth, 1978) and of the pig (Perry et al., 1973 ;Heap et al., 1975).On the other hand the uterine fluid contains large amounts of progesterone (Seamark and Lutwak-Mann, 1972 ;Fuchs and Beling, 1974 ;Cowman et al., 1976 ;Borland et at., 1977 ;Fowler et al., 1977) and oestrogens Borland et al., 1977). This has induced many workers to assume that the hormones found in the preimplantation blastocyst have an uterine origin (Seamark and LutwakMann, 1972 ;Borland et al., 1977 ;Fujimoto and Sundaram, 1978 ;Singh and Booth, 1978). This hypothesis seems to be confirmed also by the scarcity of smooth endoplasmic reticulum and tubular mitochondria (Borland et al.,1977) and by the marked pinocytotic activity (Beier and Maurer, 1975) Dey, 1973, 1974a, b ;Dey and Dickmann, 1974a ;, mouse (Dey and Dickmann, 19746), rabbit and hamster (Dickmann and Gupta, 1974 ;Niimura and Ishida, 1976). According to the autonomous production by the preimplantation embryo of steroid hormones plays an important role in the regulation of embryonic metabolism, in the transformation of the morula to blastocyst, in the loss of the zona pellucida and in implantation.The data on this subject in the literature on bovines are scarce, relating mostly to the endocrine processes regulating implantation. In p...

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Evidence for Early Ovarian Recognition of Blastocysts in Rabbits

Cited by 67 publications

References 0 publications

Accumulation of steroids in rabbit preimplantation blastocysts

Accumulation of steroids in rabbit preimplantation blastocysts

A stimulatory effect of the fluid from preimplantation rabbit blastocysts upon luteinization of monkey granulosa cell cultures

Histochemical demonstration of steroidogenic activity in preimplantation bovine embryos

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