Use of CAT scan to determine mammary gland development of sows injected with growth hormone releasing factor during gestation and (or) lactation

2003 ◽  
Vol 83 (1) ◽  
pp. 67-72 ◽  
Author(s):  
D. Petitclerc and C. Farmer
Keyword(s):  
Growth Hormone ◽  
Mammary Gland ◽  
Mammary Development ◽  
Tissue Mass ◽  
Growth Hormone Releasing Factor ◽  
Parenchymal Tissue ◽  
Tissue Weight ◽  
Cat Scan ◽  
Biochemical Measurements ◽  
Gland Development

Fifty-two Yorkshire × Landrace gilts were allotted to: (1) saline injections (CTL; n = 17) thrice daily during gestation (day 100 to parturition) and lactation (days 3 to 29); (2) s.c. injections of 12 mg of GRF (1-29)NH2 thrice daily from day 100 of gestation to parturition (GEST; n = 12); (3) s.c. injections of 12 mg of GRF thrice daily from days 3 to 29 of lactation (LACT; n = 11); and (4) s.c. injections of 12 mg of GRF thrice daily during gestation (day 100 to parturition) and lactation (days 3 to 29) (GEST-LACT; n = 12). All sows were slaughtered on day 30 of lactation and mammary glands were excised and stored frozen at -20°C. Mammary development was measured on half of the thawed mammary gland with CAT scanning, and standard dissection and previously published biochemical measurements of mammary development were used to assess the contralateral half; correlation analyses were used to compare the two approaches. Volume of parenchymal tissue of GEST-LACT sows was 19% smaller than that of sows subjected to other treatments (GEST × LACT interaction, P = 0.01). Total mammary gland volume (r = 0.68; P = 0.002) and extraparenchymal tissue volume (r = 0.77; P < 0.001) measured by CAT scanning were correlated with extraparenchymal tissue weight obtained by tissue dissection. However, none of the CAT scan measurements were correlated with parenchymal tissue weight (P > 0.1). In conclusion, exogenous GRF given to sows during lactation affected cell volume/differentiation of the mammary gland. For mammary gland assessment in lactating sows, the CAT scan technique accurately measured the weight and volume of extraparenchymal tissue but not parenchymal tissue mass. Key words: Sows, mammary gland, mammary development, CAT scan, growth hormone-releasing factor, lactation

Plane of nutrition and folic acid supplementation between birth and four months of age on mammary development of dairy heifers

1999 ◽  
Vol 79 (2) ◽  
pp. 227-234 ◽  
Author(s):  
D. Petitclerc ◽  
P. Dumoulin ◽  
H. Ringuet ◽  
J. Matte ◽  
C. Girard
Keyword(s):  
Growth Hormone ◽  
Body Weight ◽  
Folic Acid ◽  
Mammary Gland ◽  
Folic Acid Supplementation ◽  
Mammary Development ◽  
Acid Supplementation ◽  
Parenchymal Tissue ◽  
Dairy Heifers ◽  
Ad Libitum

Forty-seven dairy heifers of approximately 10 d of age were assigned randomly to a 2 × 2 factorial design to study the effects of folic acid supplementation (0 vs. 40 mg) administered weekly i.m. and levels of feed intake after weaning on mammary development. Folic acid treatment started immediately and all heifers were weaned 5 wk later. Heifers were then either fed ad libitum grass hay and concentrates or restricted to a body weight gain of approximately 700 g d−1 until slaughter at 4 mo of age. Average daily gain was affected by feed intake level after weaning (615 vs. 954 g d−1P < 0.01); however, folic acid supplementation increased weight gain only during the 5-wk period following weaning (P < 0.05). Heifers fed ad libitum were 33% heavier before slaughter (P < 0.001) but there was no effect due to folic acid supplementation (P > 0.05). There was no effect of treatments on serum prolactin and growth hormone concentrations (P > 0.05); overall, prolactin increased and growth hormone decreased over the 16-wk sampling period. However, serum IGF-1 concentrations were significantly higher in heifers fed ad libitum following weaning as compared with the feed-restricted animals (P < 0.001); overall, IGF-1 concentrations increased linearly between weeks 2 and 16 (P < 0.001). Plane of nutrition did not have any effect (P > 0.05) on the total volume of parenchymal tissue in the mammary gland (61.6 vs. 63.6 cm3); however, ad libitum feeding increased significantly (P < 0.001) the volume of extraparenchymal tissue in the gland (262.0 vs. 1067.6 cm3). After adjusting data for the difference in body weight at slaughter, the amount of parenchymal tissue was smaller in animals fed ad libitum (P < 0.05); this adjustment did not change the effect of plane of nutrition on mammary extraparenchymal tissue. In conclusion, a fast rate of gain after weaning up to 4 mo of age induced a large accumulation of mammary fat, but did not negatively affect the total amount of parenchymal tissue in the mammary gland of dairy heifers. Key words: Plane of nutrition, folic acid, mammary gland, IGF-1

Mammary gland development of sows injected with growth hormone-releasing factor during gestation and(or) lactation

1997 ◽  
Vol 77 (2) ◽  
pp. 335-338 ◽  
Author(s):  
C. Farmer ◽  
G. Pelletier ◽  
P. Brazeau ◽  
D. Petitclerc
Keyword(s):  
Growth Hormone ◽  
Mammary Gland ◽  
Key Words ◽  
Mammary Gland Development ◽  
Mammary Glands ◽  
Late Gestation ◽  
Chemical Analyses ◽  
Growth Hormone Releasing Factor ◽  
Mammary Cell ◽  
Gland Development

Twenty-four gilts received s.c. injections of saline or growth hormone-releasing factor (GRF) in late gestation and(or) lactation. Sows were sacrificed on day 30 of lactation and functional mammary glands were excised for chemical analyses. Weight of parenchymal (P = 0.004) and extra-parenchymal tissues (P = 0.002) were decreased with GRF injections during lactation. Parenchymal mass per milligram of DNA also decreased (P = 0.025) with GRF in lactation while parenchymal DNA concentration increased (P = 0.03). Exogenous GRF given to sows during lactation therefore decreased total parenchymal mass, increased cell density and decreased mammary cell size. Key words: Sow, mammary gland, growth hormone-releasing factor

Expression levels of STAT5A and STAT5B in mammary parenchymal tissue from Upton-Meishan and Large White gilts

2002 ◽  
Vol 82 (4) ◽  
pp. 507-518 ◽  
Author(s):  
M. F. Palin ◽  
D. Beaudry ◽  
C. Roberge ◽  
C. Farmer
Keyword(s):  
Mammary Gland ◽  
Mammary Gland Development ◽  
Target Genes ◽  
Mammary Glands ◽  
Mammary Tissue ◽  
Mrna Levels ◽  
Large White ◽  
Parenchymal Tissue ◽  
Tissue Weight ◽  
Gland Development

The implication of STAT5A and STAT5B in mammary gland development and maintenance of lactation is well documented in rodents and humans. However, little is known regarding their roles in mammary gland development during gestation in pigs. We identified and analyzed the complete coding sequences of swine STAT5A and STAT5B and evaluated their mRNA levels in mammary glands of gestating gilts (day 110) in two different breeds, Upton-Meishan and Large White. Sequence analysis revealed a new APASA insertion in the STAT5A amino acid sequence that is in close proximity to residue Tyr 699 and whose phosporylation leads to the activation of target genes’ transcription. STAT5A mRNA levels were higher in Upton-Meishan than in Large White. In both breeds, STAT5B mRNA levels were higher than those of STAT5A , which is contrary to what was found in other mammals. A correlation between circulating IGF-I levels and STAT5B mRNA levels in the mammary gland was noticed in the Upton-Meishan breed only. STAT5B mRNA levels in mammary tissue of Large White gilts were highly correlated with extra-parenchymal tissue weight, parenchymal tissue weight, total parenchymal DNA, RNA and RNA/DNA ratio. In Upton-Meishan gilts, correlations were observed only between extra-parenchymal weight and STAT5A and STAT5B mRNA levels. These results indicate that there are significant differences in mRNA levels of STAT5A and STAT5B in the mammary glands of pregnant gilts when compared to other mammals, and between swine breeds. Key words: Mammary glands, signal transducers, pregnancy, kinases, pig, expression

scholarly journals A Functional Connection between pRB and Transforming Growth Factor β in Growth Inhibition and Mammary Gland Development

2009 ◽  
Vol 29 (16) ◽  
pp. 4455-4466 ◽  
Author(s):  
Sarah M. Francis ◽  
Jacqueline Bergsied ◽  
Christian E. Isaac ◽  
Courtney H. Coschi ◽  
Alison L. Martens ◽  
...  
Keyword(s):  
Mammary Gland ◽  
Growth Factor ◽  
Growth Inhibition ◽  
Mammary Gland Development ◽  
Transforming Growth Factor ◽  
Critical Role ◽  
Transforming Growth Factor Β ◽  
Mammary Development ◽  
Functional Connection ◽  
Gland Development

ABSTRACT Transforming growth factor β (TGF-β) is a crucial mediator of breast development, and loss of TGF-β-induced growth arrest is a hallmark of breast cancer. TGF-β has been shown to inhibit cyclin-dependent kinase (CDK) activity, which leads to the accumulation of hypophosphorylated pRB. However, unlike other components of TGF-β cytostatic signaling, pRB is thought to be dispensable for mammary development. Using gene-targeted mice carrying subtle missense changes in pRB (Rb1 ΔL and Rb1NF ), we have discovered that pRB plays a critical role in mammary gland development. In particular, Rb1 mutant female mice have hyperplastic mammary epithelium and defects in nursing due to insensitivity to TGF-β growth inhibition. In contrast with previous studies that highlighted the inhibition of cyclin/CDK activity by TGF-β signaling, our experiments revealed that active transcriptional repression of E2F target genes by pRB downstream of CDKs is also a key component of TGF-β cytostatic signaling. Taken together, our work demonstrates a unique functional connection between pRB and TGF-β in growth control and mammary gland development.

The role of prolactin and growth hormone in mammary gland development

2002 ◽  
Vol 197 (1-2) ◽  
pp. 127-131 ◽  
Author(s):  
Paul A Kelly ◽  
Anne Bachelot ◽  
Cécile Kedzia ◽  
Lothar Hennighausen ◽  
Christopher J Ormandy ◽  
...  
Keyword(s):  
Growth Hormone ◽  
Mammary Gland ◽  
Mammary Gland Development ◽  
Gland Development

scholarly journals Strain-Specific Differences in the Mechanisms of Progesterone Regulation of Murine Mammary Gland Development

Endocrinology ◽  
2008 ◽  
Vol 150 (3) ◽  
pp. 1485-1494 ◽  
Author(s):  
Mark D. Aupperlee ◽  
Alexis A. Drolet ◽  
Srinivasan Durairaj ◽  
Weizhong Wang ◽  
Richard C. Schwartz ◽  
...  
Keyword(s):  
Mammary Gland ◽  
Mammary Gland Development ◽  
Nuclear Factor Κb ◽  
Mammary Development ◽  
Normal Mammary Gland ◽  
Human Populations ◽  
Induced Expression ◽  
Altered Expression ◽  
Downstream Effectors ◽  
Gland Development

Progesterone (P) is required for normal mammary gland development, and is implicated in the etiology of mammary cancer in rodents and humans. We analyzed mammary gland developmental responses to P and estrogen (E) in two strains of mice (BALB/c and C57BL/6) that exhibit differences in ductal development at sexual maturity and alveologenesis during pregnancy. C57BL/6 mice exhibited reduced proliferative and morphological responses to P. Analysis of known mediators of sidebranching and alveologenesis revealed that reduced P-induced expression of P receptor isoform B and receptor activator of nuclear factor-κB ligand (RANKL), as well as altered expression and regulation of cyclin D1, CCAAT/enhancer binding protein β, and the downstream effectors of RANKL, nuclear Id2 and p21, contribute significantly to the reduced P responsiveness of the C57BL/6 mammary gland. In contrast, E responsiveness was greater in C57BL/6 than in BALB/c glands. E may play a compensatory role in C57BL/6 alveologenesis through its effect on the induction and activation of signal transducer and activator of transcription 5a, a known regulator of RANKL. These observations suggest that in human populations with heterogeneous genetic backgrounds, individuals may respond differentially to the same hormone. Thus, genetic diversity may have a role in determining the effects of P in normal mammary development and tumorigenesis. Reduced progesterone-induced expression of progesterone receptor and RANKL, altered expression and regulation of C/EBPβ, and of the downstream effectors of RANKL, nuclear Id2 and p21, contribute significantly to the reduced progesterone-responsiveness of the C57BL/6 mammary gland compared to the BALB/c gland.

scholarly journals Food intake dependent and independent effects of heat stress on lactation and mammary gland development

2020 ◽  
Author(s):  
Yao Xiao ◽  
Jason M. Kronenfeld ◽  
Benjamin J. Renquist
Keyword(s):  
Heat Stress ◽  
Mammary Gland ◽  
Food Intake ◽  
Milk Production ◽  
Mammary Gland Development ◽  
Heat Exposure ◽  
Mammary Development ◽  
Late Gestation ◽  
Independent Effects ◽  
Gland Development

ABSTRACTWith a growing population, a reliable food supply is increasingly important. Heat stress reduces livestock meat and milk production. Genetic selection of high producing animals increases endogenous heat production, while climate change increases exogenous heat exposure. Both sources of heat exacerbate the risk of heat-induced depression of production. Rodents are valuable models to understand mechanisms conserved across species. Heat exposure suppresses feed intake across homeothermic species including rodents and production animal species. We assessed the response to early-mid lactation or late gestation heat exposure on milk production and mammary gland development/function, respectively. Using pair-fed controls we experimentally isolated the food intake dependent and independent effects of heat stress on mammary function and mass. Heat exposure (35°C, relative humidity 50%) decreased daily food intake. When heat exposure occurred during lactation, hypophagia accounted for approximately 50% of the heat stress induced hypogalactia. Heat exposure during middle to late gestation suppressed food intake, which was fully responsible for the lowered mammary gland weight of dams at parturition. However, the impaired mammary gland function in heat exposed dams measured by metabolic rate and lactogenesis could not be explained by depressed food consumption. In conclusion, mice recapitulate the depressed milk production and mammary gland development observed in dairy species while providing insight regarding the role of food intake. This opens the potential to apply genetic, experimental and pharmacological models unique to mice to identify the mechanism by which heat is limiting animal production.Summary StatementsThis study demonstrates that heat stress decreases lactation and mammary development through food intake dependent and independent mechanisms.

scholarly journals Baicalin Promotes Mammary Gland Development via Steroid-Like Activities

2021 ◽  
Vol 9 ◽  
Author(s):  
Weizhen Chen ◽  
Wei Wei ◽  
Liya Yu ◽  
Xin Zhang ◽  
Fujing Huang ◽  
...  
Keyword(s):  
Mammary Gland ◽  
Tumor Growth ◽  
Cell Line ◽  
Cancer Progression ◽  
Mammary Gland Development ◽  
Biological Activities ◽  
Xenograft Model ◽  
Mammary Development ◽  
Tumor Xenograft ◽  
Gland Development

Baicalin, the main flavonoid component extracted from Scutellaria roots, has a variety of biological activities and is therefore used in the treatment of many kinds of diseases. However, whether baicalin affects the normal development of tissues and organs is still unclear. Here, using a mouse mammary gland model, we investigated the effects of baicalin on the expansion of mammary stem cells (MaSCs) and mammary development, as well as breast cancer progression. Interestingly, we found that baicalin administration significantly accelerates duct elongation at puberty, and promotes alveolar development and facilitates milk secretion during pregnancy. Furthermore, self-renewal of MaSCs was significantly promoted in the presence of baicalin. Moreover, in a tumor xenograft model, baicalin promoted tumor growth of the MDA-MB-231 cell line, but suppressed tumor growth of the ZR-751 cell line. Mechanistically, baicalin can induce expression of the protein C receptor, while inhibiting the expression of the estrogen receptor. Transcriptome analysis revealed that baicalin is involved in signaling pathways related to mammary gland development, immune response, and cell cycle control. Taken together, our results from comprehensive investigation of the biological activity of baicalin provide a theoretical basis for its rational clinical application.

scholarly journals Evidence That the Mammary Fat Pad Mediates the Action of Growth Hormone in Mammary Gland Development

Endocrinology ◽  
1998 ◽  
Vol 139 (2) ◽  
pp. 659-662 ◽  
Author(s):  
Paul D. Walden ◽  
Weifeng Ruan ◽  
Mark Feldman ◽  
David L. Kleinberg
Keyword(s):  
Growth Hormone ◽  
Mammary Gland ◽  
Mammary Gland Development ◽  
Fat Pad ◽  
Mammary Fat Pad ◽  
Gland Development
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