In vitro analysis of the hormonal basis for the sexual dimorphism in the embryonic development of the mouse mammary gland

Development ◽  
1971 ◽  
Vol 25 (1) ◽  
pp. 141-153
Author(s):  
Klaus Kratochwil
Keyword(s):  
Mammary Gland ◽  
Sexual Dimorphism ◽  
Embryonic Development ◽  
Mammary Glands ◽  
Mouse Mammary Gland ◽  
Female Type ◽  
Male Type ◽  
Endocrine Organs ◽  
Vitro Analysis

Factors underlying the sexual dimorphism in the embryonic development of mouse mammary glands were analysed in vitro and the following results were obtained: 1. Mammary gland rudiments of 13-day male embryos, explanted immediately before the onset of their regression, were perfectly capable of developing into female-type glands in vitro. Even some of the glands of 14-day male embryos, where the regression process had already begun, recovered after explantation and underwent female-type morphogenesis. 2. Combined explantation of 13-day testes with mammary rudiments of female embryos of 12–14 days gestation resulted in male-type regression of the glands. 3. The addition of testosterone to the culture medium caused a similar regression of explanted (female) mammary-gland rudiments. The minimal effective concentration of the hormone was 10−9m, or 0·00029 μg/ml. 4. Cultured mammary rudiments of 15-day female embryos were no longer responsive to the presence of testis explants. They failed to undergo regression and continued their development in vitro. From these results the following conclusions were drawn: (a) The sexual dimorphism in the embryonic development of mouse mammary glands is caused by their suppression in males and not by their stimulation in female embryos. (b) The androgenic hormones in male foetuses are solely responsible for the regression of the mammary rudiments. They exert their effect directly on the gland without the need for involvement of other endocrine organs. (c) The genetic sex of the gland itself has no influence on its developmental capacities as: (i) glands of male embryos are able to develop in the absence of androgens, and (ii) glands of female embryos undergo typical male-type regression in vitro when exposed to the presence of foetal testes or of testosterone.

INTERACTION BETWEEN PROLACTIN AND THYROXINE IN MOUSE MAMMARY GLAND LOBULO-ALVEOLAR DEVELOPMENT IN VITRO

1969 ◽  
Vol 45 (4) ◽  
pp. 579-583 ◽  
Author(s):  
D. V. SINGH ◽  
H. A. BERN
Keyword(s):  
Mammary Gland ◽  
Synergistic Effects ◽  
Synthetic Medium ◽  
Mammary Glands ◽  
Mouse Mammary Gland ◽  
Intact Female ◽  
Antagonistic Effects ◽  
Alveolar Development ◽  
Development In Vitro

SUMMARY Intact female BALB/cCrgl mice, 3–4 weeks old, were pretreated with oestrogen and progesterone for 9 days. Whole mammary glands from these mice were cultivated for 5 days in a synthetic medium supplemented with aldosterone (A), prolactin (MH) and insulin (I), with and without thyroxine (T4) at concentrations ranging from 0·01 to 5 μg./ml. A medium containing 1 μg. A +5 μg.MH +5 μg.I/ml. was generally optimal for lobulo-alveolar development. Addition of thyroxine to this combination resulted in a decrease in development which was highly significant at higher concentrations. However, when cultures were maintained in media containing suboptimal or low amounts of prolactin (1 μg. A + 3 μg. MH +5 μg. I/ml. and 1 μg. A + 1 μg. MH +5 μg. I/ml., respectively), the results indicate two possible effects of thyroxine: lower amounts of thyroxine had synergistic effects, whereas greater amounts had antagonistic effects on lobulo-alveolar development.

scholarly journals Local Insulin-Like Growth Factor-II Mediates Prolactin-Induced Mammary Gland Development

2003 ◽  
Vol 17 (3) ◽  
pp. 460-471 ◽  
Author(s):  
Russell C. Hovey ◽  
Jessica Harris ◽  
Darryl L. Hadsell ◽  
Adrian V. Lee ◽  
Christopher J. Ormandy ◽  
...  
Keyword(s):  
Mammary Gland ◽  
Early Pregnancy ◽  
Insulin Receptors ◽  
Mammary Glands ◽  
Mouse Mammary Gland ◽  
Mammary Epithelial ◽  
Receptor Expression ◽  
Mammary Tissue ◽  
Alveolar Development

Abstract Prolactin (PRL) is a major determinant of mammary epithelial cell proliferation during alveolar development in sexually mature and pregnant mice. To date, it has not been clear whether PRL effects these responses alone or by also invoking the action of autocrine/paracrine growth factors. In this study, we provide evidence that part of the effect of PRL on mammary gland growth is mediated by IGF-II. During sexual maturity and in early pregnancy, the level of IGF-II mRNA in the mammary gland was increased concurrent with increased PRL receptor expression. The level of IGF-II mRNA was reduced in mammary tissue from PRL receptor−/− mice during early pregnancy, and explants of mouse mammary gland and HC11 mammary epithelial cells both increased their expression of IGF-II after exposure to PRL in vitro. These findings coincided with the demonstration that IGF-II stimulated alveolar development in mammary glands in whole organ culture. PRL was most efficacious in stimulating IGF-II gene transcription from promoter 3 of the mouse IGF-II gene in vitro. Insight into the mechanism by which PRL induced IGF-II expression was provided by the fact that it was blocked by the Jak2 inhibitor AG490 and the MAPK inhibitor PD98059. Finally, induction of insulin receptor substrate (IRS)-1 in the mammary glands of PRL-treated mice and induction of IRS-1 and IRS-2 after treatment with PRL plus progesterone indicates that these molecules are induced by PRL as potential signaling intermediates downstream from IGF-I/insulin receptors. Together, these data demonstrate a role for IGF-II as a mediator of PRL action in the mouse mammary gland during ductal branching and alveolar development.

Development of sexual dimorphism in the suprachiasmatic nucleus of the rat

1982 ◽  
Vol 95 (1) ◽  
pp. 137-145 ◽  
Author(s):  
Christine B. Le Blond ◽  
Stephen Morris ◽  
George Karakiulakis ◽  
Ruth Powell ◽  
P. J. Thomas
Keyword(s):  
Sexual Dimorphism ◽  
Suprachiasmatic Nucleus ◽  
Normal Male ◽  
Female Type ◽  
Male Development ◽  
Neonatal Androgenization ◽  
Male Type ◽  
Neonatal Castration

Synapses develop at similar rates in the suprachiasmatic nucleus of rats of both sexes, but values are higher in male than in female animals from birth to maturity. Male-type development cannot be mimicked by neonatal androgenization but results suggest that female-type development can be induced by neonatal castration of males. The results suggested that both prenatal and postnatal androgens are essential to normal male development.

THE IN VITRO METABOLISM OF MAMMARY GLAND SLICES IN THE PRESENCE OF POSTERIOR PITUITARY LOBE EXTRACTS RICH IN MELANOPHORE-DISPERSING ACTIVITY

1957 ◽  
Vol 15 (4) ◽  
pp. 366-373 ◽  
Author(s):  
T. R. BRADLEY ◽  
G. M. MITCHELL
Keyword(s):  
Mammary Gland ◽  
Guinea Pigs ◽  
Incubation Medium ◽  
Mammary Glands ◽  
Gas Evolution ◽  
Early Lactation ◽  
Posterior Pituitary ◽  
Rats And Mice ◽  
Posterior Pituitary Lobe

SUMMARY Slices cut from mammary glands of rats and mice during gestation and lactation were incubated in vitro in the presence of pig posterior pituitary lobe extracts rich in melanophore-dispersing ('B') activity. Slices taken in early lactation but not during gestation or late lactation showed increased net gas evolution compared with control slices. Similar tissue from rabbits and guinea-pigs did not give rise to this effect, nor did slices of other tissues taken from lactating rats. The increased net gas evolution was not observed in the absence of glucose from the incubation medium. Treatment of the 'B' extract with NaOH or hypophysectomy of the rats prior to use decreased the response.

scholarly journals Evidence that the stimulation of lipogenesis in the mammary glands of starved lactating rats re-fed with a chow diet is dependent on continued hepatic gluconeogenesis during the absorptive period. Effects of a gluconeogenic inhibitory, mercaptopicolinic acid, in vivo

1985 ◽  
Vol 228 (3) ◽  
pp. 727-733 ◽  
Author(s):  
D H Williamson ◽  
V Ilic ◽  
R G Jones
Keyword(s):  
Mammary Gland ◽  
Phosphoenolpyruvate Carboxykinase ◽  
Mammary Glands ◽  
Hepatic Glycogen ◽  
Chow Diet ◽  
Hepatic Gluconeogenesis ◽  
Rapid Stimulation ◽  
Stimulation Of

The rapid stimulation of lipogenesis in mammary gland that occurs on re-feeding starved lactating rats with a chow diet was decreased (60%) by injection of mercaptopicolinic acid, an inhibitor of hepatic gluconeogenesis at the phosphoenolpyruvate carboxykinase step. Mercaptopicolinate had no effect on lipogenesis in mammary glands of fed lactating rats. The inhibition of lipogenesis persisted in vitro when acini from mammary glands of re-fed rats treated with mercaptopicolinate were incubated with [1-14C]glucose. Mercaptopicolinate added in vitro had no significant effect on lipogenesis in acini from starved-re-fed lactating rats. Mercaptopicolinate prevented the deposition of glycogen and increased the rate of lipogenesis in livers of starved-re-fed lactating rats, whereas it had no significant effect on livers of fed lactating rats. Administration of intraperitoneal glucose restored the rate of mammary-gland lipogenesis in re-fed rats treated with mercaptopicolinate to the values for re-fed rats. Hepatic glycogen deposition was also restored, and the rate of hepatic lipogenesis was stimulated 5-fold. It is concluded that stimulation of mammary-gland lipogenesis on re-feeding with a chow diet after a period of starvation is in part dependent on continued hepatic gluconeogenesis during the absorptive period. Possible sources of the glucose precursors are discussed.

BIOLOGICAL ACTIONS OF HUMAN SOMATOTROPHIN AND ITS DERIVATIVES ON MOUSE MAMMARY GLAND AND TELEOST URINARY BLADDER

1977 ◽  
Vol 73 (2) ◽  
pp. 377-383 ◽  
Author(s):  
B. A. DONEEN ◽  
H. A. BERN ◽  
CHOH HAO LI
Keyword(s):  
Mammary Gland ◽  
Urinary Bladder ◽  
Tertiary Structure ◽  
Biological Activities ◽  
Mouse Mammary Gland ◽  
Performic Acid ◽  
Acid Oxidation ◽  
Peptide Fragments ◽  
Ovine Prolactin

SUMMARY These studies are concerned with the structural and functional evolution of the ancestrally related pituitary prolactins and somatotrophins. Prolactin-like biological activities of human somatotrophin (hGH) and its peptide fragments were bioassayed in vitro on the mouse mammary gland and the teleost urinary bladder. Plasmin modified-hGH was as active as hGH in both bioassays. The NH2-terminal 134-residue fragment possessed about 10% of the lactogenic and urinary bladder potency of hGH, whereas the CO2H-terminal 51-residue fragment was inactive at the concentrations observed. These results suggest that the same regions of primary structure are responsible for the prolactin-like actions of hGH on the target organs of lower and higher vertebrates. Alteration of the tertiary structure of hGH, human chorionic somatomammotrophin, and ovine prolactin by performic acid oxidation destroys the mammary gland activities of these hormones.

scholarly journals The dynamics of morphological changes during in vitro aging of bovine virgin mammary gland neutrophils

2012 ◽  
Vol 47 (No. 12) ◽  
pp. 325-332 ◽  
Author(s):  
Z. Sládek ◽  
D. Vašíčková ◽  
D. Ryšánek
Keyword(s):  
Mammary Gland ◽  
Trypan Blue ◽  
Morphological Changes ◽  
Membrane Integrity ◽  
Mammary Glands ◽  
Progressive Increase ◽  
Apoptotic Bodies ◽  
Bovine Mammary Gland ◽  
Cell Counts

The present study was an in vitro analysis of the dynamics of bovine mammary gland neutrophil apop­tosis based on the detection of morphological changes. The neutrophils were isolated from mammary glands of five virgin heifers. The mammary glands were lavaged, the suspensions were then bacteriologically examined, and total and differential cell counts were made. The cells were cultivated in vitro for 4 hours. After 2, 3 and 4 hours of cultivation, they were panoptically stained, and the proportions of apoptotic neutrophils and trypan blue positive neutrophils were determined. Neutrophil apoptosis and impaired cytoplasmic membrane integrity of neutrophils were already observed in the mammary gland lavages (11.9% and 0.8%, respectively). During the cultivation, a progressive increase in the number of apoptotic neutrophils in various stages of apoptosis – karyopyknosis, zeiosis and apoptotic bodies – was observed. Karyopyknotic neutrophils represented a dominant part of the apoptotic neutrophil population in the course of the whole cultivation. The most intensive increase was observed in zeiosis, whereas the levels of apoptotic bodies remained the same. After 4 hours of cultivation, 31.7% apoptotic neutrophils and 9.8% trypan blue positive neutrophils (i.e. Secondary necrotic cells) were found. The results of this work show that spontaneous apoptosis and secondary neutrophil necrosis must be taken into account during in vitro cultivations of bovine mammary gland neutrophils.

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