Localization and expression of BCAT during pregnancy and lactation in the rat mammary gland

2001 ◽  
Vol 280 (3) ◽  
pp. E480-E488 ◽  
Author(s):  
Armando R. Tovar ◽  
Enrique Becerril ◽  
Rogelio Hernández-Pando ◽  
Gabriel López ◽  
Agus Suryawan ◽  
...  

During lactation, branched-chain aminotransferase (BCAT) gene expression increases in the mammary gland. To determine the cell type and whether this induction is present only during lactation, female rats were randomly assigned to one of three experimental groups: pregnancy, lactation, or postweaning. Mammary gland BCAT activity during the first days of pregnancy was similar to that of virgin rats, increasing significantly from day 16 to the last day of pregnancy. Maximal BCAT activity occurred on day 12 of lactation. During postweaning, BCAT activity decreased rapidly to values close to those observed in virgin rats. Analyses by Western and Northern blot revealed that changes in enzyme activity were accompanied by parallel changes in the amount of enzyme and its mRNA. Immunohistochemical studies of the mammary gland showed a progressive increase in mitochondrial BCAT (mBCAT)-specific staining of the epithelial acinar cells during lactation, reaching high levels by day 12. Immunoreactivity decreased rapidly after weaning. There was a significant correlation between total BCAT activity and milk production. These results indicate that the pattern of mBCAT gene expression follows lactogenesis stages I and II and is restricted to the milk-producing epithelial acinar cells. Furthermore, BCAT activity is associated with milk production in the mammary gland during lactation.

2002 ◽  
Vol 69 (1) ◽  
pp. 13-26 ◽  
Author(s):  
AURORE RINCHEV-ALARNOLD ◽  
LUCETTE BELAIR ◽  
JEAN DJIANE

Secretory IgA found in external secretions are constituted by polymeric IgA (pIgA) bound to the extra-cellular part of the polymeric immunoglobulin receptor (pIgR). The receptor mediates transcytosis of pIgA across epithelial cells. The aim of the present study was to analyse the evolution of pIgR expression in the sheep mammary gland during the development of the mammary gland and to analyse its hormonal regulation. Gene expression of the pIgR was analysed in sheep mammary gland during pregnancy and lactation. By Northern Blot analysis, we observed that low levels of pIgR mRNA are expressed until day 70 of pregnancy. Accumulation of pIgR mRNA started during the third part of pregnancy and intensified 3 d after parturition to reach highest levels during established lactation (day 70). In situ hybridization analysis was used to confirm the increase in pIgR gene expression per mammary epithelial cell. In order to examine the hormonal regulation of the pIgR expression, virgin ewes were hormonally treated. Treatment with oestradiol and progesterone increased pIgR mRNA levels slightly. Subsequent addition of glucocorticoids induced a significant accumulation of pIgR mRNA in the mammary gland of the treated animals. Immunohistochemical analysis was performed to verify that the increase of pIgR mRNA level was associated with enhancement of the pIgR protein in mammary cells. No increase of pIgR mRNA levels were observed if PRL secretion was blocked by bromocryptine injections throughout the hormonal procedure. In conclusion, the present experiments suggest that the enhancement of pIgR levels during lactation result from combined effects of both prolactin and glucocorticoids.


2005 ◽  
Vol 289 (4) ◽  
pp. E634-E642 ◽  
Author(s):  
Craig P. Hasilo ◽  
Christopher R. McCudden ◽  
J. Ryan J. Gillespie ◽  
Kathi A. James ◽  
Edward R. Hirvi ◽  
...  

In most mammalian tissues, the stanniocalcin-1 gene (STC-1) produces a 50-kDa polypeptide hormone known as STC50. Within the ovaries, however, the STC-1 gene generates three higher-molecular-mass variants known as big STC. Big STC is targeted locally to corpus luteal cells to block progesterone release. During pregnancy and lactation, however, ovarian big STC production increases markedly, and the hormone is released into the serum. During lactation, this increase in hormone production is dependent on a suckling stimulus, suggesting that ovarian big STC may have regulatory effects on the lactating mammary gland. In this report, we have addressed this possibility. Our results revealed that virgin mammary tissue contained large numbers of membrane- and mitochondrial-associated STC receptors. However, as pregnancy progressed into lactation, there was a decline in receptor densities on both organelles and a corresponding rise in nuclear receptor density, most of which were on milk-producing, alveolar cells. This was accompanied by nuclear sequestration of the ligand. Sequestered STC resolved as one ∼135-kDa band in the native state and therefore had the appearance of a big STC variant. However, chemical reduction collapsed this one band into six closely spaced, lower-molecular-mass species (28–41 kDa). Mammary gland STC production also underwent a dramatic shift during pregnancy and lactation. High levels of STC gene expression were observed in mammary tissue from virgin and pregnant rats. However, gene expression then fell to nearly undetectable levels during lactation, coinciding with the rise in nuclear targeting. These findings have thus shown that the mammary glands are indeed targeted by STC, even in the virgin state. They have further shown that there are marked changes in this targeting pathway during pregnancy and lactation, accompanied by a switch in ligand source (endogenous to exogenous). They also represent the first example of nuclear targeting by STC.


2013 ◽  
Vol 238 (9) ◽  
pp. 1033-1046 ◽  
Author(s):  
Isabelle R Miousse ◽  
Horacio Gomez-Acevedo ◽  
Neha Sharma ◽  
Jamie Vantrease ◽  
Leah Hennings ◽  
...  

2022 ◽  
Vol 82 ◽  
Author(s):  
L. S. Santos ◽  
R. J. B. Matos ◽  
G. S. Cordeiro ◽  
G. S. Perez ◽  
D. A. E. Santo ◽  
...  

Abstract Exposure to the hight-fat diet may alter the control of food intake promoting hyperphagia and obesity. The objective of this study was to investigate the effects of this diet on dopamine receptors (drd1 and drd2), proopiomelanocortin (pomc), neuropeptideY (npy) genes expression, and preference food in adult rats. Wistar female rats were fed a hight-fat or control diet during pregnancy and lactation. The offspring were allocated into groups: Lactation – Control (C) and High-fat (H). Post-weaning – Control Control (CC), offspring of mothers C, fed a control diet after weaning; Control Hight-fat (CH), offspring of mothers C, fed a hight-fat diet after weaning; Hight-fat Control (HC), offspring of mothers H, fed with control diet after weaning; and Hight-fat Hight-fat (HH), offspring of mothers H, fed a H diet after weaning. The groups CH and HH presented greater expression of drd1 in comparison to the CC. The drd2 of CH and HC presented higher gene expression than did CC. HH presented higher pomc expression in comparison to the other groups. HC also presented greater expression in comparison to CH. The npy of HH presented greater expression in relation to CH and HC. HH and HC have had a higher preference for a high-fat diet at 102º life’s day. The high-fat diet altered the gene expression of the drd1, drd2, pomc and npy, and influencing the food preference for high-fat diet.


1991 ◽  
Vol 280 (3) ◽  
pp. 671-677 ◽  
Author(s):  
J L Jaeger ◽  
N Shimizu ◽  
J D Gitlin

Using a ceruloplasmin cDNA clone in RNA blot analysis, a single 3.7 kb ceruloplasmin-specific transcript was detected in rat mammary gland tissue from pregnant and lactating animals. Ceruloplasmin gene expression in the mammary gland was tissue-specific, with no evidence of expression in brain, heart or other extrahepatic tissues. Ceruloplasmin mRNA was also detected in mammary gland tissue from male, virgin female and non-pregnant/multiparous animals, and the abundance of ceruloplasmin-specific transcripts in virgin female rats was independent of their stage of oestrus. In virgin female mammary gland the content of ceruloplasmin mRNA was 20% of that in hepatic tissue from these animals and approx. 2-3-fold greater than that found in mammary gland tissue of pregnant or lactating animals. Development studies revealed ceruloplasmin gene expression in male and female mammary gland by only 2 weeks of age, prior to the onset of puberty. Biosynthetic studies indicated that the ceruloplasmin mRNA in mammary gland tissue was translated into a 132 kDa protein qualitatively similar to that synthesized in liver. By in situ hybridization, ceruloplasmin gene expression was localized to the epithelium lining the mammary gland alveolar ducts, without evidence of expression in the surrounding mesenchyme. Ceruloplasmin gene expression was also detected in a human breast adenocarcinoma cell line and in biopsy tissue from women with invasive ductal carcinoma. Taken together, these data indicate that the mammary gland is a prominent site of extrahepatic ceruloplasmin gene expression and add to the evidence that ceruloplasmin biosynthesis is associated with growth and differentiation in non-hepatic tissues.


1995 ◽  
Vol 110 (1-2) ◽  
pp. 81-87 ◽  
Author(s):  
Roberto Rosato ◽  
Héle`ne Jammes ◽  
Lucette Belair ◽  
Claudine Puissant ◽  
Jean-Pierre Kraehenbuhl ◽  
...  

1980 ◽  
Vol 238 (1) ◽  
pp. E26-E31 ◽  
Author(s):  
P. B. Mutch ◽  
L. S. Hurley

The effect of dietary zinc deficiency during late pregnancy and lactation on the rat mammary gland was investigated by feeding female rats either a zinc-deficient diet (0.4 ppm Zn) or a zinc-sufficient diet (100 ppm Zn) ad libitum or restricted in amount. Zinc deficiency from day 0 of lactation specifically reduced the total RNA content of lactating mammary glands on day 14, but had no effect beyond that of food restriction on their total DNA content, Both RNA and DNA content of the mammary gland were decreased by reduced food intake. Zinc deficiency from day 14 of pregnancy to day 2 of lactation severely impaired parturition and prevented the normal rise in mammary gland RNA seen during lactogenesis in control animals. A shorter deficiency period, from day 18 of gestation, had no effect on mammary gland nucleic acids other than that due to inanition.


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