THE INITIATION AND MAINTENANCE OF LACTATION IN THE MARSUPIAL, TRICHOSURUS VULPECULA

1962 ◽  
Vol 25 (3) ◽  
pp. 375-385 ◽  
Author(s):  
G. B. SHARMAN
Keyword(s):  
Mammary Gland ◽  
Post Partum ◽  
Virgin Female ◽  
Normal Growth ◽  
Mammary Glands ◽  
Mammary Development ◽  
Oestrous Cycle ◽  
Trichosurus Vulpecula ◽  
Pregnant Females ◽  
Micro Anatomy

SUMMARY The mammary glands of the marsupial Trichosurus vulpecula (the brush possum) showed a cycle of development and regression correlated with the oestrous cycle. Mammary glands of pregnant females were not significantly heavier than those of non-pregnant females at comparable times after oestrus. There were no clear differences in histology between mammary glands of mated and non-mated females at the same number of days after oestrus until the 17th day. At this time the mammary glands of three non-mated females were clearly different from the glands of three post-partum females. Lactation was initiated in six out of eight non-mated females, including one virgin female, by transferring newborn young, which attached themselves to teats, to their pouches. Of the six transferred young which attached all, except one, lived and showed normal growth. The rate of regression of previously suckled mammary glands was slower in lactating than in non-lactating females. No clear evidence was obtained of hypertrophy of the non-suckled mammary gland following the attachment of a single young to the teat of the alternate mammary gland. However, the micro-anatomy of the non-suckled gland at 8 days after the onset of lactation suggested that milk may have distended the alveoli. These observations are discussed in relation to the control of lactation in the female marsupial. It is suggested that, in marsupials, the hormones circulating during the oestrous cycle cause full mammary development and that the suckling stimulus of the newborn young is sufficient to initiate lactation. The yolk-sac placenta of the brush possum apparently plays no essential part in mammary gland development. Otherwise the pattern of lactation in the brush possum does not appear to differ from that of eutherian mammals.

THE DISTRIBUTION OF [1,2-3H]TESTOSTERONE IN THE TISSUES OF FEMALE RATS

1966 ◽  
Vol 34 (4) ◽  
pp. 491-496 ◽  
Author(s):  
D. Y. WANG ◽  
STRETTON YOUNG ◽  
R. D. BULBROOK
Keyword(s):  
Mammary Gland ◽  
Post Partum ◽  
Virgin Female ◽  
Mammary Glands ◽  
Female Rats ◽  
Pregnant Rat ◽  
Tumour Bearing ◽  
Mesenteric Fat

SUMMARY (1) The incorporation of [1,2-3H]testosterone in vivo into various tissues of virgin, pregnant, post-partum and tumour-bearing female rats was studied. (2) In virgin female rats the clearance of radioactivity from mesenteric fat, mammary gland, uterus, spleen, lung and blood was similar. This similarity in the rates of clearance of radioactivity for all the tissues examined was also found for the tissues of pregnant, post-partum, and tumour-bearing rats. (3) After the administration of [1,2-3H]testosterone different amounts of radioactivity were found in each of the tissues examined. In virgin rats the levels of incorporation were fat > uterus ≥ mammary gland > lung > blood ≥ spleen. This pattern was also obtained in post-partum and tumour-bearing animals; the tumours in the latter behaved in a similar way to normal mammary glands. In the pregnant rat, the foetus incorporated the least amount of radioactivity.

Studies of the oestrous cycle, oestrus and pregnancy in the koala (Phascolarctos cinereus)

Reproduction ◽  
2000 ◽  
pp. 49-57 ◽  
Author(s):  
SD Johnston ◽  
MR McGowan ◽  
P O'Callaghan ◽  
R Cox ◽  
V Nicolson
Keyword(s):  
Luteal Phase ◽  
Post Partum ◽  
Plasma Concentrations ◽  
External Genitalia ◽  
Oestrous Cycle ◽  
Phascolarctos Cinereus ◽  
Pregnant Females ◽  
Peripheral Plasma ◽  
The Mean ◽  
High Concentrations

As an integral part of the development of an artificial insemination programme in the captive koala, female reproductive physiology and behaviour were studied. The oestrous cycle in non-mated and mated koalas was characterized by means of behavioural oestrus, morphology of external genitalia and changes in the peripheral plasma concentrations of oestradiol and progestogen. The mean (+/- SEM) duration of the non-mated oestrous cycle and duration of oestrus in 12 koalas was 32.9 +/- 1.1 (n = 22) and 10.3 +/- 0.9 (n = 24) days, respectively. Although the commencement of oestrous behaviour was associated with increasing or high concentrations of oestradiol, there were no consistent changes in the morphology or appearance of the clitoris, pericloacal region, pouch or mammary teats that could be used to characterize the non-mated cycle. As progestogen concentrations remained at basal values throughout the interoestrous period, non-mated cycles were considered non-luteal and presumed anovulatory. After mating of the 12 koalas, six females gave birth with a mean (+/- SEM) gestation of 34.8 +/- 0.3 days, whereas the remaining six non-parturient females returned to oestrus 49.5 +/- 1. 0 days later. After mating, oestrous behaviour ceased and the progestogen profile showed a significant increase in both pregnant and non-parturient females, indicating that a luteal phase had been induced by the physical act of mating. Progestogen concentrations throughout the luteal phase of the pregnant females were significantly higher than those of non-parturient females. Parturition was associated with a decreasing concentration of progestogen, which was increased above that of basal concentrations until 7 days post partum.

scholarly journals Left–right analysis of mammary gland development in retinoid X receptor-α +/− mice

2016 ◽  
Vol 371 (1710) ◽  
pp. 20150416 ◽  
Author(s):  
Jacqulyne P. Robichaux ◽  
John W. Fuseler ◽  
Shrusti S. Patel ◽  
Steven W. Kubalak ◽  
Adam Hartstone-Rose ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Mammary Gland ◽  
Breast Cancer Risk ◽  
Cancer Risk ◽  
Bilateral Symmetry ◽  
Mammary Glands ◽  
Network Size ◽  
Mammary Development ◽  
Retinoid X Receptor ◽  
Breast Development

Left–right (L–R) differences in mammographic parenchymal patterns are an early predictor of breast cancer risk; however, the basis for this asymmetry is unknown. Here, we use retinoid X receptor alpha heterozygous null (RXRα +/− ) mice to propose a developmental origin: perturbation of coordinated anterior–posterior (A–P) and L–R axial body patterning. We hypothesized that by analogy to somitogenesis—in which retinoic acid (RA) attenuation causes anterior somite pairs to develop L–R asynchronously—that RA pathway perturbation would likewise result in asymmetric mammary development. To test this, mammary glands of RXRα +/− mice were quantitatively assessed to compare left- versus right-side ductal epithelial networks. Unlike wild-type controls, half of the RXRα +/− thoracic mammary gland (TMG) pairs exhibited significant L–R asymmetry, with left-side reduction in network size. In RXRα +/− TMGs in which symmetry was maintained, networks had bilaterally increased size, with left networks showing greater variability in area and pattern. Reminiscent of posterior somites, whose bilateral symmetry is refractory to RA attenuation, inguinal mammary glands (IMGs) also had bilaterally increased network size, but no loss of symmetry. Together, these results demonstrate that mammary glands exhibit differential A–P sensitivity to RXRα heterozygosity, with ductal network symmetry markedly compromised in anterior but not posterior glands. As TMGs more closely model human breast development than IMGs, these findings raise the possibility that for some women, breast cancer risk may initiate with subtle axial patterning defects that result in L–R asymmetric growth and pattern of the mammary ductal epithelium. This article is part of the themed issue ‘Provocative questions in left–right asymmetry’.

Assessment of mammary gland metabolism in the sow: II. Cellular metabolites in the mammary secretion and plasma during lactogenesis II

1995 ◽  
Vol 62 (2) ◽  
pp. 207-220 ◽  
Author(s):  
Craig S. Atwood ◽  
Janine K. Toussaint ◽  
Peter E. Hartmann
Keyword(s):  
Mammary Gland ◽  
Metabolic Activity ◽  
Inorganic Phosphate ◽  
De Novo ◽  
Post Partum ◽  
Acid Synthesis ◽  
Mammary Glands ◽  
Progressive Increase ◽  
Progressive Decrease ◽  
Lactose Synthesis

SUMMARYThe concentrations of lactose, glucose, glucose 6-phosphate, glucose 1-phosphate, UDPglucose, UDPgalactose, UDP, UMP, inorganic phosphate, ADP and AMP (metabolites involved in the lactose synthesis pathway), and cAMP, galactose and fructose were measured in the mammary secretion from sucked (n = 9) and unsucked (n = 4) mammary glands of nine sows during the first 5 d post partum. The concentrations of lactose, glucose, galactose and fructose were also measured in plasma during this time. The progressive increase in the concentration of lactose, and changes in the concentrations of cellular metabolites in the mammary secretion from sucked glands were consistent with an increase in the metabolic activity of those glands during lactogenesis II. In contrast, unsucked glands showed a progressive decrease in the concentration of lactose, while the concentrations of cellular metabolites in the milk generally remained unchanged. These results indicated that there was no increase in the metabolic activity of unsucked glands (no increase in lactose synthesis or utilization of glucose and ATP) and that the rate of lactose synthesis prior to milk removal was limited by the availability of glucose and/or UDPgalactose. Therefore, the removal of colostrum from the mammary gland was necessary for an increase in the rate of lactose synthesis (and probably de novo fatty acid synthesis) and implies that autocrine mechanisms are operating to control the rate of milk synthesis during lactogenesis in the sow. The low concentration of glucose in colostrum compared with that in plasma is discussed in view of the paracellular pathway.

EFFECT OF SUCKLING AND OF EXTEROCEPTIVE STIMULATION UPON PROLACTIN RELEASE IN THE RAT DURING LATE LACTATION

1972 ◽  
Vol 52 (1) ◽  
pp. 11-22 ◽  
Author(s):  
F. MENA ◽  
C. E. GROSVENOR
Keyword(s):  
Mammary Gland ◽  
Post Partum ◽  
Mammary Glands ◽  
The Other ◽  
Male Rats ◽  
Milk Secretion ◽  
Suckling Period ◽  
Prolactin Release ◽  
Other Hand ◽  
Rat Pituitary

SUMMARY The results of experiments in which the prolactin in the primiparous rat pituitary was bioassayed suggested that the failure of suckling to release prolactin after 8 h of non-suckling on day 21 post-partum was due to the fact that prolactin had been discharged from the pituitary during the 8-h non-suckling period, presumably by exteroceptive signals emanating from the general environment of the animal room. This was substantiated in other experiments in which prolactin release was assessed indirectly through its stimulatory effects upon milk secretion. In these experiments, the mammary glands of rats maintained continuously in the animal room filled faster on day 21 after complete emptying of the glands by exogenous oxytocin, than did either rats on day 14 post-partum maintained continuously in the animal room or rats isolated in a room without other rats on day 21 post-partum. The glands of the latter two groups of rats could be stimulated to fill faster provided prolactin was injected 4 h before the initial emptying of the glands. The exteroceptive stimuli in the animal room environment that stimulated the release of prolactin in the 21-day post-partum rat apparently emanated at least in part from other lactating rats and/or their litters, since faster mammary gland refilling occurred in isolated 21 day post-partum rats when they were exposed to the presence of lactating rats with their litters for 30 min halfway through the 8-h non-suckling period which preceded the initial emptying of the gland. Exposure to male rats, on the other hand, was totally ineffective. A release of prolactin occurred in response to animal room environmental stimuli in the day 14 primiparous rat provided 13–14 day old foster pups were inserted in place of the mother's own pups on day 7. Thus, the rapidly changing characteristics of the pups from 14 to 21 days of age in some manner is involved in the increasing responsiveness of the exteroceptive mechanism for prolactin release which occurs from day 14 to day 21 post-partum.

Suppression of ovarian secretions before puberty strongly affects mammogenesis in the goat

2012 ◽  
Vol 79 (2) ◽  
pp. 157-167 ◽  
Author(s):  
Lucile Yart ◽  
Laurence Finot ◽  
Pierre-Guy Marnet ◽  
Frédéric Dessauge
Keyword(s):  
Mammary Gland ◽  
Progesterone Receptors ◽  
Antigen Expression ◽  
Mammary Glands ◽  
Cell Number ◽  
Mammary Development ◽  
Border Region ◽  
Nuclear Antigen ◽  
Mammary Tissue ◽  
Pcr Analysis

The objective of this study was to provide insight into the biological mechanisms underlying mammary development and the role of the ovaries in prepubertal caprine mammogenesis using a serial ovariectomy approach. Young Alpine goats were ovariectomized (Ovx) or sham-operated (Int) at three periods before puberty (G1=1 month, G2=2 month and G3=3 months of age) and one after puberty (G7=7 months of age). The goats were slaughtered at 9 months of age and mammary glands were removed. Ovariectomy performed at 1, 2 and 3 months of age caused a 50% reduction in DNA concentration, in mammary tissue taken from the parenchyma-stroma border region. Morphological analysis of mammary tissue sections indicated that the parenchymal structures of Ovx goats were negatively affected by ovariectomy. Goats ovariectomized before 2 months of age (Ovx-1 and Ovx-2) showed a significant decrease in the percent of cells proliferating in mammary glands of 9-month old goats (proliferating cell nuclear antigen expression and antigen Ki67-positive cell number). Also, goats ovariectomized at 1 and 2 months of age had reduced matrix metalloprotease 2 activity at 9 months of age. E-cadherin was strongly decreased in goats ovariectomized before 2 months of age (80 and 85% in Ovx-1 and Ovx-2 goats, respectively). Quantitative PCR analysis of transcripts encoding for oestrogen (ERα) and progesterone receptors (PR) and immunodetection of ERα showed that ovariectomy at 1 and 2 months of age strongly inhibited the transcription of ERα and PR in the mammary gland. We conclude that ovariectomy before 3 months of age markedly impaired parenchymal development. These findings suggest that prepubertal mammogenesis in goats depends on the ovaries to initiate mammary epithelial cell proliferation and mammary gland remodelling.

scholarly journals Insulin-like growth factor binding protein-5 (IGFBP-5) induces premature cell death in the mammary glands of transgenic mice

Development ◽  
2002 ◽  
Vol 129 (19) ◽  
pp. 4547-4557 ◽  
Author(s):  
Elizabeth Tonner ◽  
Michael C. Barber ◽  
Gordon J. Allan ◽  
James Beattie ◽  
John Webster ◽  
...  
Keyword(s):  
Growth Hormone ◽  
Cell Death ◽  
Mammary Gland ◽  
Transgenic Mice ◽  
Dna Content ◽  
Caspase 3 ◽  
Transgenic Animals ◽  
Mammary Glands ◽  
Mammary Development ◽  
Igf I

We have previously demonstrated that IGFBP-5 production by mammary epithelial cells increases dramatically during involution of the mammary gland. To demonstrate a causal relationship between IGFBP-5 and cell death we created transgenic mice expressing IGFBP-5 in the mammary gland using a mammary-specific promoter, β-lactoglobulin. DNA content in the mammary glands of transgenic mice was decreased as early as day 10 of pregnancy. Histological analysis indicated reduced numbers of alveolar end buds, with decreased ductal branching. Transgenic dams produced IGFBP-5 in their milk at concentrations similar to those achieved at the end of normal lactation. Mammary cell number and milk synthesis were both decreased by approximately 50% during the first 10 days of lactation. BrdU labelling was decreased, whereas DNA ladders were increased in transgenic animals on day 1 of lactation. On day 2 postpartum, the epithelial invasion of the mammary fat pad was clearly impaired in transgenic animals. The concentrations of the pro-apoptotic molecule caspase-3 and of plasmin were both increased in transgenic animals whilst the concentrations of 2 prosurvival molecules Bcl-2 and Bcl-xLwere both decreased. In order to examine whether IGFBP-5 acts by inhibiting the survival effect of IGF-I we examined IGF receptor phosphorylation and Akt phosphorylation and showed that both were inhibited. We attempted to “rescue” the transgenic phenotype by using growth hormone to increase endogenous IGF-I concentrations or by implanting minipumps delivering an IGF-1 analogue, R3-IGF-1, which binds weakly to IGFBP-5. Growth hormone treatment failed to affect mammary development suggesting that increased concentrations of endogenous IGF-1 are insufficient to overcome the high concentrations of IGFBP-5 produced by these transgenic animals. In contrast mammary development (gland weight and DNA content) was normalised by R3-IGF-I although milk production was only partially restored. This is the first demonstration that over-expression of IGFBP-5 can lead to; impaired mammary development, increased expression of the pro-apoptotic molecule caspase-3, increased plasmin generation and decreased expression of pro-survival molecules of the Bcl-2 family. It clearly demonstrates that IGF-I is an important developmental/survival factor for the mammary gland and, furthermore, this cell death programme may be utilised in a wide variety of tissues.

Breeding of a Captive Colony of Notomys fuscus Wood Jones (Rodentia : Muridae)

1980 ◽  
Vol 7 (3) ◽  
pp. 379 ◽  
Author(s):  
HJ Aslin ◽  
CHS Watts
Keyword(s):  
Breeding Season ◽  
Vaginal Bleeding ◽  
Post Partum ◽  
Reproductive Rate ◽  
Oestrous Cycle ◽  
Gestation Period ◽  
Pregnant Females ◽  
Delayed Implantation ◽  
Lactating Females

Reproductive data were obtained from a captive colony of N. fuscus over 10 years. Females had an oestrous cycle averaging 7.4 days, and a gestation period averaging 34.3 days. Only three possible instances of post-partum mating were recorded, but. some lactating females returned to oestrus 14-22 days after birth of their young. There was no evidence of delayed implantation due to lactation. Vaginal bleeding occurred in pregnant females 8-17 days before birth. Seventy-four litters were born, litter sizes ranging from one to five, average 2.7. No breeding season was evident. Both sexes were reproductively mature at 70 days old. Comparisons are made with other species of Notomys, and their generally low reproductive rate discussed.

Modeling of fibrocystic mastopathy in experiment on animals

2020 ◽  
Vol 28 (4) ◽  
pp. 429-436
Author(s):  
Svetlana A. Anisimova ◽  
Janna A. Svirina ◽  
Denis A. Maksaev
Keyword(s):  
Mammary Gland ◽  
Virgin Female ◽  
Mammary Glands ◽  
Female Rats ◽  
Fibrocystic Disease ◽  
Drug Induced ◽  
Fibrocystic Mastopathy ◽  
Hormonal Imbalance ◽  
Pathogenetic Factor ◽  
Almost All

Nowadays, hormonal imbalance is proven to be a factor that influences initiation of malignant and benign breast tumors. To study the aspects of participation of sex hormones in damage to organs and tissues, it may be necessary to model a common womens pathology fibrocystic disease of mammary glands characterized by the most pronounced effects of this pathogenetic factor, on experimental animals. Aim. To create a model of fibrocystic disease of mammary gland with the subsequent possibility of studying morphological manifestations of the disease in natural and drug-induced pathomorphism. Materials and Methods. The pathology was induced by intramuscular injection of 0.5 ml of 2% synestrol and 0.5 ml of 2.5% progesterone to virgin female rats on the 1st, 7th, 14th, 21st, 28th and 35th days of the experiment. For examination, histological preparations of inguinal mammary glands were made. The preparations were described and studied using morphometric analysis. Results. In the result of the experiment, pronounced macro- and microscopic alterations of mammary glands were found. Microscopic picture was similar to that observed in fibrocystic mastopathy in women. Almost all the morphometric parameters underwent reliable alterations in correspondence with the given pathology. Conclusion. A model of fibrocystic disease of mammary gland was obtained that may be used for further study of morphogenesis and methods of correction.

PENGARUH PEMBERIAN OKSITOSIN DAUN KATU DAN DAUN LAMPES TERHADAP SEKRESI AIR SUSU DAN GAMBARAN HISTOLOGI KELENJAR AMBING PADA MENCIT

1999 ◽  
Vol 5 (1) ◽  
pp. 1
Author(s):  
I.B. Rai Pidada
Keyword(s):  
Mammary Gland ◽  
Leaf Extract ◽  
Post Partum ◽  
Mammary Glands ◽  
Physiological Solution ◽  
Ocimum Sanctum ◽  
Control Group ◽  
Lactation Period ◽  
Fourth Group ◽  
And Control

A comparative study on the effect of oxytocin, extracted leaf of katu (Sauropus androgynous, Merr) and lampes (Ocimum sanctum, Linn) against secretions of milk and histologically mammary gland of mice was carried out under laboratory conditions. The study was designed by using totally 40 mice pp and divided into four groups treatment which consisted 10 females mice post partum (pp) of each group. The control group, katu (S.androginus), lampes (O. sanctum), and oxytosin were given orally 0.5 ml physiological solution, 10 mg/0.5 ml leaf extract of S. androgynus , 10 mg/0.5 ml leaf extract of O. sanctum and 0.1 IU oxytocin intramuscular, respectively. The treatment were started on day fourt to 21th of lactation period. The data were observed on day 6th, 9th, 12th, 15th, of lactation period and than on day 21th the mice were killed to prepare histologically of mammary glands. The data analyzed by ANOVA and LSD test. The result of the study showed that the secretion of the milk on the mice were not significantly different among of fourth groups. However between S. androgynous and O. sanctum group accured an increasing on secretion of milk productions. The diameter of alveolus pit of mammae lobus gland were not significantly different amongs the fourth group, but the number of alveolus of mammae lobus gland were significantly different among oxytocin, S. androgynous, and O. sanctum group and between the group of O. sanctum and control.

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