Bioassay of Oxytocin by Changes in Light Penetration Through Rat Mammary Gland Tissue in Vitro

Bílek, Ján; Mikulás, I; Slaba, J.; Skála, I

doi:10.1677/joe.0.0510771

Cited by 3 publications

(4 citation statements)

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“…Some neuroactive and vasoactive substances such as acetylcholine, 5-hydroxytryptamine, bradykinin, arg-vasopressin and ATP also induce the contraction of myoepithelial cells [2,27,30]. We are interested in ATP because, in normal and cancerous mammary epithelial cells, mechanical stimulation induces the release of ATP, UTP and UDP from the stimulated cell, which in turn induce the cell-to-cell spreading of Ca 2+ waves [8,9,13,14].…”

Section: Introductionmentioning

confidence: 99%

Synergistic effects of ATP on oxytocin-induced intracellular Ca2+ response in mouse mammary myoepithelial cells

Nakano¹,

Furuya

Yamagishi

2001

Pflügers Arch - Eur J Physiol

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An increase in intracellular Ca2+ ([Ca2+]i) is essential for mammary myoepithelial cells to contract, leading to milk ejection during lactation. In this study, the intracellular signaling leading to the increase in [Ca2+]i in cultured myoepithelial cells from mouse lactating mammary glands was investigated using fura-2 fluorescence ratiometry. [Ca2+]i increased in cultured myoepithelial cells in response to either oxytocin (1 nM) or ATP (10 microM), and the cells then contracted. These [Ca2+]i responses were diminished by treatment with an inhibitor of phospholipase C (> or = 1 microM U73122). Intracellular application of inositol 1,4,5-trisphosphate (IP3: 10 or 100 microM) increased [Ca2+]i. Pretreatment with pertussis toxin (PTX: 0.1 or 1 microgram/ml) inhibited the [Ca2+]i response to ATP, but had less of an effect on the response to oxytocin. These results indicate that oxytocin and purinergic receptors are coupled to PTX-insensitive and PTX-sensitive G proteins, respectively, and that their activation leads to the increase in [Ca2+]i through the release of Ca2+ from IP3-sensitive intracellular stores via the inositol-phospholipid signaling pathway. Furthermore, we found that the [Ca2+]i responses to oxytocin at physiological doses (0.01-0.1 nM) were augmented in the presence of a sub-responsive dose of ATP (1 microM). The activation of purinergic receptors may facilitate myoepithelial cell contraction in milk-ejection responses.

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Section: Introductionmentioning

confidence: 99%

Synergistic effects of ATP on oxytocin-induced intracellular Ca2+ response in mouse mammary myoepithelial cells

Nakano¹,

Furuya

Yamagishi

2001

Pflügers Arch - Eur J Physiol

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“…Other workers have used the mammary gland in vitro; a strip of tissue is suspended in an organ bath, and the increases in tension caused by oxytocin are recorded (Mendez-Bauer, Cabot & CaldeyroBarcia, 1960;Ryden & Sj6holm, 1962;Roca et al, 1972 between the application of oxytocin and the expulsion of droplets of milk is related to the concentration of hormone applied (Van Dongen & Hays, 1966). It is also possible to measure the changes in transparency induced by oxytocin in a flat segment of mammary gland (Bilek, Mikulas, Slaba& Skala, 1971). Methods in vivo are less satisfactory than those in vitro in a number of ways.…”

Section: Discussionmentioning

confidence: 99%

“…Of the in vitro methods, the droplet expulsion method of Van Dongen & Hays (1966), though very sensitive, can be criticized on a number of grounds (Cowie & Tindal, 1971), not least because the index of precision (X) is more than 1, which makes it unsuitable for routine assays. The transparency method described by Bilek et aL (1971) is more promising; it is sensitive and has a satisfactory index of precision. On the other hand the preparation reacts to small quantities of other substances as well as to oxytocin.…”

Section: Discussionmentioning

confidence: 99%

“…Alternatively, fragments of gland may be observed under a microscope; the latent period between the application of oxytocin and the expulsion of droplets of milk is related to the concentration of hormone applied (Van Dongen & Hays, 1966). It is also possible to measure the changes in transparency induced by oxytocin in a flat segment of mammary gland (Bilek, Mikulas, Slaba& Skala, 1971). Methods in vivo are less satisfactory than those in vitro in a number of ways.…”

Section: Discussionmentioning

confidence: 99%

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Bioassay of Oxytocin on the Superfused Mammary Gland of the Mouse, Using an Automatic Apparatus

Robinson¹,

Walker²

1974

British J Pharmacology

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A sensitive method of assaying oxytocin using the superfused mouse mammary gland is described. The method is shown to be reliable, accurate and precise. Assays are performed automatically and the preparation is stable for at least 18 hours. The preparation is relatively insensitive to bradykinin, histamine, 5‐hydroxytryptamine, angiotensin, prostaglandin F2α, adrenaline and noradrenaline. The contractions produced by acetylcholine can be abolished by atropine without the sensitivity to oxytocin being affected. Vasopressin has a variable activity on the preparation; its potency can be as high as one‐fifth that of oxytocin. It is concluded that this method compares favourably with other published methods.

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Neurohypophysial hormones

Bisset

1976

Peptide Hormones

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Bioassay of Oxytocin by Changes in Light Penetration Through Rat Mammary Gland Tissue in Vitro

Cited by 3 publications

References 0 publications

Synergistic effects of ATP on oxytocin-induced intracellular Ca2+ response in mouse mammary myoepithelial cells

Synergistic effects of ATP on oxytocin-induced intracellular Ca2+ response in mouse mammary myoepithelial cells

Bioassay of Oxytocin on the Superfused Mammary Gland of the Mouse, Using an Automatic Apparatus

Neurohypophysial hormones

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