Rat Placental Hormonal Activities Corresponding to Those of Pituitary Mammotropin

Ray, Esten W.; Averill, Stuart C.; Lyons, William R.; Johnson, Ruth E.

doi:10.1210/endo-56-4-359

Cited by 86 publications

(25 citation statements)

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“…Lactogenesis occurred in ovariectomized, foetectomized rats treated with CB 154, which suggests that the lactogenic factor can be derived from the placenta, and is probably placental lactogen. These findings are in agreement with the results of Ray et al (1955), who demonstrated that placental extracts have lactogenic properties when administered together with hydrocortisone acetate to hypophysectomized and ovariectomized rats.…”

Section: Ovariectomized Ratssupporting

confidence: 93%

The Foetoplacental Unit and the Initiation of Lactation in the Rat

Nicholas¹,

Hartmann²

1981

Aust. Jnl. Of Bio. Sci.

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Rats were either Caesarean-sectioned, ovariohysterectomized or ovariectomized on day 19 of gestation anti the role of prolactin and corticosteroids in the initiation of lactation was studied by administering 2~bromo-lX-ergocryptine (CB 154) and prolactin, and by using adrenalectomy and foetectomY. The concentrations of corticosteroids and prolactin in the plasma and the weight and lactose content of the inguinal mammary glands were determined 48 h after Caesarean section, and 24 h after ovariohysterectomy and ovariectomy.The ranges in concentrations of corticosteroids, prolactin and mammary lactose were 207-348 JIg/l plasma, 21·9-65·3 JIg/l plasma and 1·21--4·50mg/g tissue, respectively, in the Caesareansectioned, ovariohysterectomized and ovariectomized rats. The administration of CB 154 after either Caesarean section, ovariohysterectomy or ovariectomy decreased the concentration of prolactin to less than 8· 8 Jig/I. Whereas CB 154 significantly depressed the lactose content of the mammary tissue in Caesarean-sectioned and ovariohysterectomized rats (0·42 and o· 31 mg/g tissue, respectively), no effect was observed in ovariectomized rats (1·39 mg/g tissue). The administration of ovine prolactin reversed the inhibitory effects of CB 154. Furthermore, in two rats which were both ovariectomized and foetectomized, CB 154 did not inhibit lactose accumulation in the mammary tissue (2·02 mg/g tissue).Adrenalectomy of ovariohysterectomized rats decreased corticosteroid concentrations from 348 to 14 JIg/l plasma and the lactose content of mammary tissue from 1 . 31 to O· 19 mg/g tissue. Whereas adrenalectomy of ovariectomized rats decreased corticosteroid concentrations to 53 Jig/I, the lactose content of mammary tissue (1·82 mg/g tissue) remained within the range for ovariohysterectomized rats.These findings show that hormones produced in late pregnancy by the foetus and placenta can support lactogenesis in the rat in the absence of maternal prolactin and corticosteroids.

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Section: Ovariectomized Ratssupporting

confidence: 93%

The Foetoplacental Unit and the Initiation of Lactation in the Rat

Nicholas¹,

Hartmann²

1981

Aust. Jnl. Of Bio. Sci.

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“…Ovariectomy or fetectomy of pregnant rats and mice has no significant effect on mammogenesis, either, provided that the placentae remain intact; if the placentae are removed then mammogenesis ceases (Desjardins, Paape & Tucker, 1968). Placental extracts also stimulate mammary growth in hypophysectomized, ovariectomized virgin rats when given together with steroids (Ray, Averill, Lyons & Johnstone, 1955), and, in vitro, growth of mammary expiants is promoted by co-culture with placental fragments (Forsyth & Jones, 1976).…”

Section: Systemic Endocrine Controlmentioning

confidence: 99%

Development of the mammary gland

Knight¹,

Peaker²

1982

Reproduction

139

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“…Fujii36) could not find positive crop reaction following intramuscular injection of acidic and alkaline placental extracts of any stage of pregnancy, but could prove prolactin in the placenta of rats only. Ray et al 37) report that a 12 day old placenta of a rat is equivalent to 0.01 mg. of hypophyseal prolaction in the effect of stimulat ing lactation and to about 2 mg. of it in the effect of stimulating formation of corpora lutea. Averill38), Astwood39) and Lyons also acknowledge the effect of rat placenta extract in causing positive crop reaction.…”

Section: Discussionmentioning

confidence: 99%

Prolactin-Like Substance of Human Placenta

Kurosaki

1961

Tohoku J. Exp. Med.

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Rat Placental Hormonal Activities Corresponding to Those of Pituitary Mammotropin

Cited by 86 publications

References 0 publications

The Foetoplacental Unit and the Initiation of Lactation in the Rat

The Foetoplacental Unit and the Initiation of Lactation in the Rat

Development of the mammary gland

Prolactin-Like Substance of Human Placenta

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