Hormonal Control of Lactation

Folley, S. J.

doi:10.1016/b978-0-12-395712-2.50021-x

Cited by 11 publications

(3 citation statements)

References 178 publications

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“…The pertinent experimental evidence has been adequately reviewed by Folley & Malpress [19486], who formulated the 'double threshold' theory of oestrogen activity. During the last decade there has been considerable controversy concerning the lactogenic and antilactogenic properties of the oestrogens.…”

Section: Resultsmentioning

confidence: 99%

Studies on the Hormonal Induction of Mammary Growth and Lactation in the Goat

Cowie¹,

Folley²,

Malpress³

et al. 1952

J Endocrinol

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Extensive morphological and functional investigations have been carried out on the artificial induction of mammary development and lactation in the goat using hexoestrol alone and in combination with progesterone, at several dose levels and proportions. Administration of the oestrogen and progesterone was either by tablet implantation or by subcutaneous injection in oily solution. Forty animals were used, of which twenty-three were ovariectomized during infancy. Special histological techniques were devised for studying and estimating quantitatively the degree of mammary development. In the later experiments this was achieved by surgically removing one half of the udder, i.e. one gland, when the lactation curve had reached a maximum. In three normally lactating goats the operation had no influence on the milk yield of the remaining gland.For the dose levels used, the milk yields of the animals receiving oestrogen and those receiving oestrogen and progesterone did not differ significantly. In general, the artificially induced milk yields were below the expected yields had the animals come into lactation after kidding.It appeared highly probable that the total area of secretory epithelium in the artificially developed gland was less than in the normally developed udder. A high correlation was observed between the surface area of the secretory epithelium in the entire half udder and the milk yield.Several marked abnormalities were observed in the microscopic structure of the udders. These were less evident in the glands of the goats receiving progesterone provided the oestrogen dose was not excessive.Since the original demonstration by Folley, Scott Watson & Bottomley [1940, 1941] that udder growth and copious lactation could be elicited in the virgin goat by treat¬ ment with synthetic oestrogens without supplementary treatment with anteriorpituitary lactogenic hormones, numerous spectacular applications of this procedure to farm animals (mainly bovines) have been described. These studies up to 1947 have been reviewed by Malpress [1947]. Since that time further studies have been made on the bovine [

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Section: Resultsmentioning

confidence: 99%

Studies on the Hormonal Induction of Mammary Growth and Lactation in the Goat

Cowie¹,

Folley²,

Malpress³

et al. 1952

J Endocrinol

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“…In these, certain changes in milk composition which occurred following the injection of 25 mg OB persisted even after the inhibitory action of the oestrogen on milk secretion had ceased. If we attempt to interpret these in terms of the double threshold theory of Folley & Malpress [1947], then the increase in non-fatty solids could result from considerably smaller additions to the circulating oestrogen than are required to inhibit milk secretion. Once started, this reaction might be of relatively long duration proceeding in the absence of a continuous supply of exogenous oestrogen.…”

Section: Discussionmentioning

confidence: 99%

Oestrogen Function in Established Lactation in the Cow

Hutton¹

1958

Journal of Endocrinology

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In a series of six experiments the effect on milk yield and composition of injecting oestradiol monobenzoate (OB) at five dose levels has been studied on seventy-six cows of the Ayrshire, Guernsey, Friesian and Shorthorn breeds.The doses ranged from 6\m=.\25to 100 mg, and all produced increases in the percentage of non\x=req-\ fatty solids. These changes were due mainly to increases in the protein, lactose and ash fractions and persisted for periods of several weeks. When more than 25 mg OB were injected, fat percentages also increased and milk yields declined. At the 12\m=.\5 mg level, significant increases occurred both in the yields of fat (lb.) and non-fatty solids (lb.). These results indicated that galactopoietic responses could be obtained only within a restricted dose-range, the limits of which were affected by stage of pregnancy and differences in breed.The considerable similarity which exists between these results and the changes occurring in the milk of pregnant cows during a normal lactation suggests that the latter are probably determined by a progressive rise in blood oestrogen levels as pregnancy advances. The results are discussed in relation to the effect of pasture oestrogens on milk composition and with regard to the possibility of improving the quality of milk by oestrogen administration.In contrast to the large number of investigations which have provided information on the role of oestrogens in mammary gland growth and development, relatively few experiments have been planned with the object of defining the functions of these hormones in established lactation. Folley [1936] and Waterman, Freud & Vos-de Jongh [1936] first showed that oestrogens could inhibit lactation in the cow and this was subsequently confirmed by Folley, Scott-Watson & Bottomley [1941] and Stanley & Owen [1941]. Since ovariectomized cows were not included in these or later studies, it was impossible to determine whether or not the presence of the ovary was required to produce this response. Recently, however, Folley [1956] has reviewed the results of similar experiments on other species and has suggested that the inhibi¬ tory action of oestrogen is probably due to a synergism between oestrogen and progesterone. Folley [1936] also provided the first evidence that oestrogens could produce changes in milk composition. These consisted of increases in the percentages of fat and non-fatty solids which in some cows persisted for several months. As a decline in milk yield at the time of injection was merely transient, Folley [1936] considered that this was an example of galactopoiesis and described it as an 'en¬ richment effect'. Similar results were obtained by Folley & Scott-Watson [1938] and Spielman, Ludwick & Petersen [1941] in experiments involving the use of synthetic rather than naturally occurring oestrogens. In an extension of this work, however, Folley et al. [1941] were less successful than previously in separating the apparent inhibitory and

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“…This is seen as a reciprocal change in the plasma concentrations of these steroids ( Fig. 2 (Nelson, 1934;Folley & Young, 1941;Meites & Turner, 1942a, b, c;Petersen, 1944;Folley & Malpress, 1948;Folley, 1952;Meites, 1954Meites, , 1956Meites & Sgouris, 1954;Meites & Nicoll, 1966).…”

Section: Methodsmentioning

confidence: 99%

Progesterone Withdrawal as the Lactogenic Trigger in the Rat

Kuhn

1969

Journal of Endocrinology

181

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SUMMARYLactogenesis, as indicated by the appearance of mammary lactose, follows ovariectomy and/or hysterectomy and the fall in the concentration of progesterone in the plasma preceding normal parturition in the pregnant rat. It is suppressed by administered progesterone in all cases, and by prolactin after hysterectomy.The natural lactogenic signal may occur 30 hr. before parturition, due to conversion of progesterone to 20\g=a\-hydroxypregn-4-en-3-one in the ovaries. Changes in the concentration of corticosterone, oestrogen and prolactin in the plasma either do not occur or do not constitute a lactogenic signal.

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Hormonal Control of Lactation

Cited by 11 publications

References 178 publications

Studies on the Hormonal Induction of Mammary Growth and Lactation in the Goat

Studies on the Hormonal Induction of Mammary Growth and Lactation in the Goat

Oestrogen Function in Established Lactation in the Cow

Progesterone Withdrawal as the Lactogenic Trigger in the Rat

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