Comparative measurement of the lactogenic activity of ovine placental lactogen in rabbit and ewe mammary gland

Servely, Jean-Luc; Emane, Moise N’Guema; Houdebiné, Louis‐Marie; Djiane, Jean; Delouis, Claude; Kelly, Paul A.

doi:10.1016/0016-6480(83)90079-5

Cited by 31 publications

(17 citation statements)

References 14 publications

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“…5) when compared with E 2 +P 4 +HC-treated ewes. This confirmed previous reports that oPL stimulated accumulation of -casein mRNA in mammary explants from pregnant ewes, although oPL was considerably less potent than oPRL (Servely et al 1983), and these results are comparable to lactogenic effects of bPL in the heifer with artificially induced lactation (Byatt et al 1994).…”

Section: Figuresupporting

confidence: 91%

“…It has been purified and characterised by several groups (Martal & Djiane 1975, Chan et al 1976, Hurley et al 1977, Reddy & Watkins 1978, Warren et al 1990, Kappes et al 1992) over the past 20 years, but the physiological role of oPL in ovine physiology remains speculative. Recent results from in vitro binding studies and in vivo studies of biological activities on ovine adult or foetal tissues suggest a role(s) in foetal growth and/or mammogenesis (Chan et al 1978a, Servely et al 1983, Freemark & Handwerger 1986, Freemark & Comer 1989, Byatt et al 1992, Anthony et al 1995. Both the cDNA sequence (Colosi et al 1989) and predicted amino acid sequence indicate that oPL has partial homology with both ovine PRL (oPRL) (49%) and ovine GH (oGH) (25%) and oPL binds to oGH receptors (oGH-R) or oPRL receptors (oPRL-R).…”

Section: Introductionmentioning

confidence: 99%

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Demonstration of in vivo mammogenic and lactogenic effects of recombinant ovine placental lactogen and mammogenic effect of recombinant ovine GH in ewes during artificial induction of lactation

Kann

Delobelle-Deroide²,

Belair³

et al. 1999

Journal of Endocrinology

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The present study demonstrates that ovine placental lactogen (oPL) (ovine chorionic somatotrophin) may have an important role in the mammogenesis and/or lactogenesis of the ewe. Its effects were compared with that already described for ovine growth hormone (oGH).In the first experiment, 40 nulliparous ewes were induced to lactate by means of a 7 day (days 1-7) oestro-progestative treatment (E 2 +P 4 ). The ewes from Group 1 (n=12) received no further treatment, while those of the other groups received either recombinant oGH (roGH, 28 µg/kg, i.m., twice daily, Group 2, n=12) or recombinant oPL (roPL, 79 µg/kg, i.m., twice daily, Group 3, n=12) from day 11 to 20. All ewes received 25 mg hydrocortisone acetate (HC) twice daily on days 18-20. Control Group 00 (n=2) received no steroid treatment at all, and the control Group 0 (n=2) received only the E 2 +P 4 treatment. Thirteen ewes (three from each experimental group and the two of each control group) were slaughtered at the end of hormone treatments (day 21) before any milking stimulus. The 27 remaining ewes from Groups 1-3 were machine-milked and milk yields recorded daily from day 21 to 76. The E 2 +P 4 treatment enhanced the plasma levels of oPRL, oGH and IGF-I between days 1 and 7 by 1·5, 2·3 and 2·6 times respectively (P=0·002); roGH treatment induced a highly significant enhancement of IGF-I plasma levels from day 11 to 20, whereas a similar effect appeared for roPL-treated ewes only from day 17 to 20 (P<0·01). Eight weeks after the last exogenous hormone injections, milk yields of both roGHand roPL-treated groups progressively rose to twice that of unsupplemented groups (P<0·001). The mammary DNA content on day 21 was higher for animals which received either oGH or oPL but, due to individual variations in so few samples (n=3), this difference was not significant. No -casein was measured in mammary tissue from control ewes, whereas steroid-treated ewes (E 2 +P 4 +HC) had higher casein concentrations regardless of subsequent hormonal treatment on days 11-20 (P<0·001). -Casein concentrations in mammary parenchyma of roGH-treated ewes did not differ from that of ewes which received only E 2 +P 4 +HC; roPL supplementation clearly enhanced expression of -casein (P<0·001).IGF-I stimulation by either roGH or roPL was more precisely examined during a second experiment, in which two twice-daily i.m. doses (58 or 116 µg/kg) of either roGH or roPL were administered to four groups of six ewes that were E 2 +P 4 treated as those of Experiment 1. A control group (n=6) received no exogenous hormone from day 11 to 13. On day 13, hourly blood samples were taken from all ewes over 11 h. Both doses of roGH significantly stimulated IGF-I in a dose-dependent manner. The 58 µg/kg dose of roPL did not significantly stimulate IGF-I, but although being somewhat less efficient than the 58 µg/kg dose of roGH, the 116 µg/kg dose of roPL significantly stimulated IGF-I secretion (P<0·001).These results suggest that mammogenesis and/or lactogenesis in the ewe is in part controlled...

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Section: Figuresupporting

confidence: 91%

Section: Introductionmentioning

confidence: 99%

Demonstration of in vivo mammogenic and lactogenic effects of recombinant ovine placental lactogen and mammogenic effect of recombinant ovine GH in ewes during artificial induction of lactation

Kann

Delobelle-Deroide²,

Belair³

et al. 1999

Journal of Endocrinology

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“…It is produced by binucleate cells of the fetal trophoblast and was first purified by Handwerger et al (1974) and Martal & Djiane (1975). Ovine chorionic somatomammotrophin shares significant structural homology with both ovine prolactin (oPRL -49%) and growth hormone (oGH -28%) and can serve as a bifunctional hormone by binding to GH or PRL receptors (Chan et al 1978a, Servely et al 1983, Colosi et al 1989, Warren et al 1990). Production of oCS was first detected in the ovine trophoblast as early as day 16 (d16) of gestation (Martal & Djiane 1977).…”

Section: Introductionmentioning

confidence: 99%

Ovine chorionic somatomammotrophin (oCS) production by isolated cotyledon cells from sheep in early and mid gestation: auto-regulation by recombinant oCS

Soares

Servely²,

Puissant³

et al. 1999

Journal of Endocrinology

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We report the ability of sheep placental cotyledonary cells, isolated at different periods of pregnancy (40 to 90 days) to produce ovine chorionic somatomammotrophin (oCS) in in vitro culture conditions. This oCS production increased gradually with stage of pregnancy. Endogenous oCS net production by isolated placental cells was increased, in a dose-dependent manner, by addition of recombinant oCS (roCS). This effect was not observed after addition of recombinant ovine growth hormone. The roCS effect was more potent on cells collected during early pregnancy. Specific immunoprecipitation of oCS revealed that roCS treatment was associated with an increased dosedependent incorporation of [35 S]methionine-[ 35 S]cysteine. These findings provide evidence that oCS may act in a paracrine/autocrine manner to up-regulate its own production during early gestation. We suggest that this autoregulation may be associated with morphological and functional differentiation of the trophoblast during the growth of the placenta.

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“…It has been shown that oCS also stimulates the protein synthesis of rabbit mammary gland in organotypic culture, inducing the synthesis of lactose and /3-casein and enhancing j3-casein m-RNA (Servely et al, 1983).…”

Section: Introductionmentioning

confidence: 99%

Ovine chorionic somatomammotropin and foetal growth

Chêne

Martal²,

Charrier³

1988

Reprod. Nutr. Dévelop.

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Comparative measurement of the lactogenic activity of ovine placental lactogen in rabbit and ewe mammary gland

Cited by 31 publications

References 14 publications

Demonstration of in vivo mammogenic and lactogenic effects of recombinant ovine placental lactogen and mammogenic effect of recombinant ovine GH in ewes during artificial induction of lactation

Demonstration of in vivo mammogenic and lactogenic effects of recombinant ovine placental lactogen and mammogenic effect of recombinant ovine GH in ewes during artificial induction of lactation

Ovine chorionic somatomammotrophin (oCS) production by isolated cotyledon cells from sheep in early and mid gestation: auto-regulation by recombinant oCS

Ovine chorionic somatomammotropin and foetal growth

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