A cytological study of the mammary gland: Golgi apparatus, trophospongium and other cytoplasmic canaliculi, mitochondria

Weatherford, Harold L.

doi:10.1002/aja.1000440204

Cited by 37 publications

(8 citation statements)

References 27 publications

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“…In the rat there appeared to be a fall in the ratio DNA : nucleus between late pregnancy and early lactation, while the value of the ratio during early involution was similar to that in late pregnancy (see also the last paragraph in this sub-section). This conclusion does not agree with the results of the majority of studies of mitotic rate in the rat mammary gland (see for example Roberts, 1921;Weatherford, 1929;Reece & Warbritton, 1953) but is not greatly at variance with the results of Jeffers (1935) and Al'tman (1945). 1) implied a constant multiplicative increase in the number of nuclei, that is, a steady mitotic rate from P 5 to L 8 in the rat mammary gland.…”

Section: Levels Of Dna During the Lactation Cyclementioning

confidence: 63%

Changes in the Mammary Glands of Rats and Mice During Pregnancy, Lactation and Involution

Munford¹

1963

Journal of Endocrinology

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The changes in the level of deoxyribonucleic acid (DNA) and in the activities of alkaline and acid phosphatases were followed in the mammary glands of rats and mice killed at intervals of 3 days during pregnancy and lactation or pregnancy, lactation and involution, respectively. Polynomial regression equations were fitted to the data after they had been transformed to a logarithmic scale. During pregnancy and lactation, the general form of the curves described by the equations were similar for DNA and alkaline phosphatase, however expressed, and for acid phosphatase, other than when expressed as a concentration per mg. of DNA. All equations had a large linear term with a smaller significant negative and/or cubic term. During most of pregnancy and in early lactation the curves showed a steep, almost linear rise. During early pregnancy the slope was somewhat lower, while in the latter part of lactation the rate of increase was small or became negative. In the mouse, when the values for animals killed during involution were included in the analyses, the equations tended to be dominated by the quadratic term, a reflexion of the steep fall in the levels of all constituents after weaning.If the assumption was accepted that the average DNA content of cells did not change during the lactational cycle, the following conclusions could be drawn. In the rat, the marked similarity of the equation for total content of DNA and for concentration of DNA (per unit weight of tissue corrected for 'milk' content) indicated that the increase, and subsequent decrease, in cell numbers was mirrored almost exactly by inverse changes in average cell mass. The equations describing changes in total content of DNA (expressed in logarithms) implied that, for both species, the mitotic rate in the mammary gland was constant, or nearly constant, for most of pregnancy and the first part of lactation. In the rat and in the mouse, the increase in total alkaline phosphatase activity during pregnancy and throughout * Present address: Massey University College, Palmerston North, New Zealand. most of lactation was in part due to an increase in the enzyme activity per cell. On the other hand, the changes in total activity of acid phosphatase seemed to be due entirely to changes in the number of cells. Preparation of homogenatesAnimals were skinned so that the mammary glands were left attached to the skin and, on the right side of the animal, the fatty pads, containing the glandular struc¬ tures, were dissected free of the skin and of extraneous muscular, connective and OHhr-Cîrj (^C D CM CO CM 00 -< © ob as tí (Ci CO I> tí CM CM co © io r-oo es tí ,-h © © TÍ CD » (M t> Q O GO O fî CO CO in t* h oíOtjih

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Section: Levels Of Dna During the Lactation Cyclementioning

confidence: 63%

Changes in the Mammary Glands of Rats and Mice During Pregnancy, Lactation and Involution

Munford¹

1963

Journal of Endocrinology

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“…1935a; Greenbaum and Slater, 1957a;Weatherford, 1929). Using biochemical parameters of mammary gland growth, Greenbaum and Slater (1957a) found the increase in tissue nitrogen rose slowly during pregnancy and lactation, but rapidly over the period of parturition.…”

Section: Review Of the Literaturementioning

confidence: 99%

“…The third phase of Feldman's (1961) scheme of the development of the KîâïïsKâry gland Is ths psricd of lactation. There have been nun-erous studies on the cytology of milk secretion at the light (Da Fano, 1922;Dempsey et , 1947;Grynfeltt, 1937;Jeffers, 1935a, b;Weatherford, 1929) and electron microscope levels (Bargmann, 1959;Bargmann et al, 1961;Bargmann and Knoop, 1959;Feldman, 1961;Girardie, 1968;Helminen and Ericsson, 1968a;Hollmann, 1959;Hollmann, 1966;Keenan e;t al_., 1972;Kurosumi et , 1968;Murad, 1970;Stein and Stein, 1967;and Wellings et , 1960). The secreting epithelial cell, based on the descriptions of the preceding authors, contains parallel-arrayed cisternae of well developed rough endoplasmic reticulum.…”

Section: Review Of the Literaturementioning

confidence: 99%

“…The increase in DNA in the mammary gland during lactation has been assumed to represent hyperplasia during early lactation (Tucker and Reece^ 1963b). It is not entirely clear how this finding can be reconciled with the observations that mitoses do not occur during lactation (Weatherford, 1929;Greenbaum and Slater, 1957a). A possible explanation might be found in the investigations of Izuo st al_.…”

Section: Histology and Cytology Of The Involuting Mammary Glandmentioning

confidence: 99%

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Effect of estrogen and progesterone on lactating rat mammary glands: a light and electron microscope study

Walker

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“…During lactation mitoses arc absent from the Uctaîing glan.d (Jeffer? ;1935a; Greenbaum and Slater, 1957a;Weatherford, 1929). Using biochemical parameters of mammary gland growth, Greenbaum and Slater (1957a) found the increase in tissue nitrogen rose slowly during pregnancy and lactation, but rapidly over the period of parturition.…”

Section: Review Of the Literaturementioning

confidence: 99%

Effect of estrogen and progesterone on lactating rat mammary glands: a light and electron microscope study

Walker¹

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A cytological study of the mammary gland: Golgi apparatus, trophospongium and other cytoplasmic canaliculi, mitochondria

Cited by 37 publications

References 27 publications

Changes in the Mammary Glands of Rats and Mice During Pregnancy, Lactation and Involution

Changes in the Mammary Glands of Rats and Mice During Pregnancy, Lactation and Involution

Effect of estrogen and progesterone on lactating rat mammary glands: a light and electron microscope study

Effect of estrogen and progesterone on lactating rat mammary glands: a light and electron microscope study

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