Lactose Synthetase: Progesterone Inhibition of the Induction of α-Lactalbumin

Turkington, Roger W.; Hill, Robert L.

doi:10.1126/science.163.3874.1458

Cited by 135 publications

(51 citation statements)

References 11 publications

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“…1973) are consistent with the finding of Turkington and Hill (1969) that progesterone affects lactose synthesis by suppressing synthesis of <x-lactalbumin. In the present study, injections of progesterone failed to affect levels of lactose in secretion of ewes treated with dexamethasone or high doses of oestrogen, reduced lactose levels in secretion of ewes treated with low doses of oestrogen and suppressed, substantially, lactose levels in secretion of ewes treated with Syntocinon.…”

Section: Prolactin Concentrationsupporting

confidence: 79%

Artificial Induction of Lactation in Ewes: The Involvement of Progesterone and Prolactin in Lactogenesis

Fulkerson¹,

Hooley²,

McDowell³

et al. 1976

Aust. Jnl. Of Bio. Sci.

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An attempt has been made to evaluate the importance of prolactin and 'progesterone withdrawal' for lactogenesis. The experimental model system used was the ovariectomized, non-pregnant ewe induced to lactate artificially by treatment with trigger hormone (either oestrogen, glucocorticoid or oxytocin) alone or in combination with progesterone. It appears from the results that prolactin is important in the lactogenic responses elicited by oestrogen and oxytocin but not as important in the response elicited by glucocorticoid. Moreover, the results suggest that, in the ewe, an appropriate positive hormonal stimulus will overcome the inhibitory influence of progesterone on lactogenesis.

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Section: Prolactin Concentrationsupporting

confidence: 79%

Artificial Induction of Lactation in Ewes: The Involvement of Progesterone and Prolactin in Lactogenesis

Fulkerson¹,

Hooley²,

McDowell³

et al. 1976

Aust. Jnl. Of Bio. Sci.

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“…Progesterone plays an important role as an inhibitor of the final stage of lactogenesis (Kuhn 1969, Turkington & Hill 1969), yet it does not inhibit milk secretion during an established lactation (Herrenkohl 1974). In mature cows, these effects may be mediated by PR or interactions with other receptors, such as the glucocorticoid receptor (Capuco & Tucker 1980).…”

Section: Discussionmentioning

confidence: 99%

“…In sexually mature animals, progesterone is necessary for the lobulo-alveolar development that occurs during pregnancy (Lyons 1958, Brisken et al 1998. During lactogenesis, a reduction in circulating levels of progesterone is necessary for induction of copious milk secretion, because progesterone inhibits effective induction of -lactalbumin synthesis and initiation of stage II lactogenesis by lactogenic hormones (Turkington & Hill 1969, Capuco & Tucker 1980, Shamay et al 1987. Although estrogen may enhance lactogenesis, it is generally thought to inhibit lactation by reducing milk secretion (Bruce & Ramirez 1970) and possibly by increasing mammary regression (Capuco et al 2003).…”

Section: Introductionmentioning

confidence: 99%

Chromosomal mapping and quantitative analysis of estrogen-related receptor alpha-1, estrogen receptors alpha and beta and progesterone receptor in the bovine mammary gland

Connor¹,

Wood²,

Sonstegard³

et al. 2005

Journal of Endocrinology

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Steroid receptors are key transcriptional regulators of mammary growth, development and lactation. Expression of estrogen receptors alpha (ER ) and beta (ER ), progesterone receptor (PR), and estrogen-related receptor alpha-1 (ERR ) have been evaluated in bovine mammary gland. The ERR is an orphan receptor that, in other species and tissues, appears to function in the regulation of estrogen-response genes including lactoferrin and medium chain acyl-CoA dehydrogenase and in mitochondrial biogenesis. Expression of ER , ER , PR and ERR was characterized in mammary tissue obtained from multiple stages of bovine mammary gland development using quantitative real-time RT-PCR. Expression was evaluated in prepubertal heifers, primigravid cows, lactating non-pregnant cows, lactating pregnant cows and nonlactating pregnant cows (n=4 to 9 animals/stage). In addition, ER , ER , PR and ERR were mapped to chromosomes 9, 10, 15 and 29 respectively, by linkage and radiation hybrid mapping. Results indicated that expression of ER , PR and ERR was largely coordinately regulated and they were present in significant quantity during all physiological stages evaluated. In contrast, ER transcripts were present at a very low concentration during all stages. Furthermore, no ER protein could be detected in bovine mammary tissue by immunohistochemistry. The ER and PR proteins were detected during all physiological states, including lactation. Our results demonstrate the presence of ER , PR and ERR during all physiological stages, and suggest a functional role for ERR and a relative lack of a role for ER in bovine mammary gland development and lactation.

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“…Confluent fibroblasts were stimulated either by fetal-calf serum (10%, v/v) or by EGF (10 ng/ml), in the presence or absence of cholera toxin at concentrations higher than those required for maximal inhibition (Fig. 4) (10) and at concentrations which are lower than those that stimulate mouse-mammary gland cells in vitro (11). It is of interest that EGF, like insulin, is a lpolypeptide with molecular weight of about 6000 which has three disulfide bridges in its structure.…”

Section: Discussionmentioning

confidence: 99%

Epidermal Growth Factor: Receptors in Human Fibroblasts and Modulation of Action by Cholera Toxin

Hollenberg

Cuatrecasas

1973

Proc. Natl. Acad. Sci. U.S.A.

302

105

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Epidermal growth factor (EGF) stimulates both DNA and RNA synthesis in contact-inhibited human fibroblasts. Stimulation of DNA synthesis is observed at concentrations as low as 3 pM, is half-maximal at 70 pM, and is maximal at 300 pM EGF. The action of EGF is similar to that of fetal-calf serum, but is distinguished by the time-course of stimulation and by the ability of serum to stimulate further those cells maximally stimulated by EGF. Cells that synthesize DNA in response to physiological concentrations of EGF (10-1" to 10-10 M) are insensitive to physiological concentrations of insulin (10-1" to 10-10 M) and respond only minimally to very high concentrations of this hormone (10-6 M). The biological activity of ECGF is paralleled by binding of this peptide to fibroblasts in a specific and saturable manner; the dissociation constant is about 800 pM. The binding of EGF is unaffected by either insulin or cholera toxin. Cholera toxin inhibits the action of both EGF and serum. Suppression of DNA synthesis is observed at 0.02 pM toxin, and is maximal at about 2 pM. Cells treated with cholera toxin at these concentrations appear to be otherwise viable by several criteria. The stimulatory effects of EGF are also inhibited by theophylline and dibutyryl cyclic AMP separately or in combination. These observations indicate that fibroblasts possess receptors for EGF by biological and physicochemical criteria, and suggest that a similar if not identical peptide may be amongst those factors in sera which stimulate cell growth. The possibility is considered that EGF and cholera toxin modulate the ability of a cell to initiate polynucleotide synthesis by way of specific cell-surface interactions which in turn alter the levels of intracellular cyclic AMP.Epidermal growth factor (EGF), a small (molecular weight = 6000) polypeptide purified from the submaxillary gland of mice, is a potent stimulator of proliferation and keratinization of epidermal tissue in several species (1). In some cells (HeLa, mouse mammary, and rabbit cornea) epidermal growth factor can stimulate the synthesis of both RNA and DNA, whereas in other cells (9-day chick-embryo epidermis and human KB) only RNA synthesis is stimulated (2). While the specific hormonal role of EGF has not been defined, the polypeptide may well serve as a model compound for those substances in serum which promote cell growth. In contrast to EGF, no natural macromolecule has been isolated in pure form which will act at physiological concentrations to inhibit rather than stimulate cell growth. The present studies demonstrate that the Vibrio cholerae exotoxin (3), whose actions in various tissues are presumably mediated by eAMIP (4), can act at very low concentrations to inhibit both RNA and DNA synthesis. Cholera toxin thus behaves in some respects as a chalone (5), and it can be used as a tool to examine the effect of specifically inhibiting the action of EGF on fibroblasts of presumably mesodermic origin.We demonstrate here that very low concentrations of EGF stimulate b...

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Lactose Synthetase: Progesterone Inhibition of the Induction of α-Lactalbumin

Cited by 135 publications

References 11 publications

Artificial Induction of Lactation in Ewes: The Involvement of Progesterone and Prolactin in Lactogenesis

Artificial Induction of Lactation in Ewes: The Involvement of Progesterone and Prolactin in Lactogenesis

Chromosomal mapping and quantitative analysis of estrogen-related receptor alpha-1, estrogen receptors alpha and beta and progesterone receptor in the bovine mammary gland

Epidermal Growth Factor: Receptors in Human Fibroblasts and Modulation of Action by Cholera Toxin

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