Detection of Messenger RNA for Gonadotropin-Releasing Hormone (GnRH) but Not for GnRH Receptors in Mouse Mammary Glands

Ikeda, Mario; Taga, Michiyoshi; Sakakibara, Hideya; Minaguchi, Hiroshi; Vonderhaar, BK

doi:10.1006/bbrc.1995.1257

Cited by 14 publications

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“…The present results show the specific distribution of annexin A5 in mammary epithelial cells, and suggest that GnRH would act on the epithelial cells at involution. Interestingly, GnRH expression was detected in the pregnant and lactating rats, but not in the virgin rats [9,18]. Further study is needed to clarify the possibility of GnRH involvement in mammary involution, and in this regard is currently underway in this laboratory.…”

Section: Discussionmentioning

confidence: 97%

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Immunohistochemical Localization of Annexin A5 in the Mammary Gland of Rats: Up-Regulation of Expression by Pup Removal

Rieanrakwong

Yonezawa

Kurusu

et al. 2010

The Journal of Veterinary Medical Science

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ABSTRACT. The distribution of annexin A5, a cytosolic protein related to gonadotropin releasing hormone action, was examined in the mammary gland of rats by immunohistochemistry with special reference to changes by lactation. Annexin A5 was observed in the interstitial tissues but not alveolar cells in virgin rats, while mammary epithelial cells became positive for annexin A5 in pregnant rats. The intensity of annexin A5 was decreased in lactating rats and dramatically increased after weaning, especially on the nucleus. When pups were removed from their dam at mid-lactation (day 10), annexin A5 was also increased on day 12. Apoptotic epithelial cells detected by terminal deoxynucleotidyl transferase nick end labeling were simultaneously increased. Annexin A5 mRNA expression of mammary tissues was increased after pup removal. These results are the first to demonstrate the distribution of annexin A5 in the mammary glands of lactating rats, and the enhanced expression in mammary epithelial cells after lactation suggests its involvement in mammary epithelial cell involution.KEY WORDS: annexin A5, mammary gland, mammary involution.

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Section: Discussionmentioning

confidence: 97%

“…Among these, variation in the expression of GnRH in mammary tissues has been reported [9,18]. In the present study, we examined the variation of annexin A5 expression in mammary tissues.…”

mentioning

confidence: 96%

Immunohistochemical Localization of Annexin A5 in the Mammary Gland of Rats: Up-Regulation of Expression by Pup Removal

Rieanrakwong

Yonezawa

Kurusu

et al. 2010

The Journal of Veterinary Medical Science

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“…Expression of the GnRH gene has been described in the mammary gland of pregnant and lactating female rats (Palmon et al, 1994) and mice (Ikeda et al, 1995). GnRHR mRNA has been found in rat mammary gland (Levi et al, 1996) but not in mouse mammary gland at any functional stage (Ikeda et al, 1995).…”

Section: Discussionmentioning

confidence: 99%

The genes for gonadotropin-releasing hormone and its receptor are expressed in human breast with fibrocystic disease and cancer

Kottler

Starzec²,

Carré

et al. 1997

Int. J. Cancer

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While gonadotropin-releasing hormone (GnRH) or GnRH receptor (GnRHR) have been reported to exist in tissues other than brain and pituitary, there is no report concerning co-expression of GnRH and GnRHR in human breast tissues. To address this question, we have examined whether mRNA for GnRH as well as GnRHR was present in different human breast samples, by employing the reverse transcriptionpolymerase chain reaction (RT-PCR) protocol followed by Southern blotting of the PCR products. Coexpression of GnRH and GnRHR genes was further confirmed by dot blot hybridization using appropriate [ 32 P]-labeled probes. We thus tested fibrocystic breast (4 cases), invasive ductal carcinomas (6 cases) and 1 adjacent non-neoplastic tissue. GnRHR and GnRH mRNAs were found in all actin-positive samples including malignant as well as nonmalignant tissues. Quantitative determinations of mRNA did not reveal significant differences between malignant and non-malignant breast samples for either GnRH or GnRHR gene expression. Our data show that neither gene was overexpressed in the breast cancer samples compared with normal breast tissue. Since GnRH agonists inhibit breast epithelial cell growth, the presence of GnRHR mRNA suggests that GnRH may specifically affect breast cell growth. Our data thus raise the possibility of an autocrine/paracrine role for GnRH in human mammary gland. Int. J. Cancer 71:595-599, 1997.r 1997 Wiley-Liss, Inc.Gonadotropin-releasing hormone (GnRH) is a decapeptide that stimulates, via a high-affinity membrane receptor (GnRHR), the synthesis and release of pituitary gonadotropin luteinizing hormone (LH) and follicle-stimulating hormone (FSH), which in turn promote development of gonadal functions (Clayton and Catt, 1981). The human GnRHR consists of 328 amino acids characterized by 7 transmembrane domains, a common feature of all G-protein-coupled receptors (Kakar et al., 1992).The existence of extra-pituitary GnRHR sites in humans is controversial. Northern blot analysis failed to detect GnRHR mRNAs in any of the non-pituitary tissues examined (Kakar et al., 1992). However, using a reverse transcriptase-polymerase chain reaction (RT-PCR) protocol, these mRNAs have been detected in granulosa-luteal cells (Peng et al., 1994) and in gynecological tumors including endometrial (Chatzaki et al., 1996) and ovarian tumors (Imai et al., 1994), as they were in breast and in prostate tumors (Kakar et al., 1994).The rationale for the chronic administration of potent GnRH analogs (GnRH-A) in therapy for hormone-dependent premenopausal breast cancer is based on the observed suppression of ovarian estrogen production resulting from the desensitization of the pituitary gland. In addition, evidence is accumulating that GnRH-A may also exert direct antiproliferative effects on breast cell lines via specific binding sites (Eidne et al., 1985(Eidne et al., , 1987Miller et al., 1985). This possibility has been strengthened by the identification by RT-PCR of mRNA for GnRHR in breast tissues (Kakar et al., 1994).The study of GnRH ...

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“…Khodr et al [1] first confirmed the presence of GnRH in placenta. After that, other groups reported that GnRH as well as gene expression and synthesis have been shown in many reproductive organs such as ovary, mammary glands, and endometrium [2][3][4][5]. GnRH synthesized by gonads could regulate the steroid hormone synthesis and metabolism in mammals' reproductive system as an autocrine factor [6].…”

Section: Introductionmentioning

confidence: 97%

Differential expression of gonadotropin-releasing hormone (GnRH) in pancreas during rat pregnancy

Wang

Cao

Jiang

et al. 2009

Endocr

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Many studies have shown that there is a relationship between gonadotropin-releasing hormone (GnRH) and glucose metabolism, but little is known about the effects of GnRH on the pancreas. Our experiment investigated the effect of GnRH on pancreatic islet cell in Sprague-Dawley (SD) rats fed with high-cholesterol diet before and during pregnancy. We found that although high-cholesterol diet led to no significant difference of GnRH mRNA levels in pancreas in nonpregnant rats, it led to a marked increase of those in pregnant rats. Furthermore, in rats fed with standard laboratory chow, no significant differences were apparent in GnRH mRNA levels before and during gestation; however, when fed with high-cholesterol diet, the GnRH mRNA levels increased significantly in pregnant rats. As results indicated both diets could lead to increase of PG mRNA in pancreas of pregnant rats. It is also demonstrated that the GnRH mRNA levels are positively associated with PG mRNA levels. Moreover, our data showed a significant increase in fasting insulin level in the Gestation group compared with Control. Such changes were contrary to the changes of GnRH level in the pancreas. This may imply that GnRH influences hormones secretion in the pancreas by autocrine and paracrine effects on islet cells.

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Detection of Messenger RNA for Gonadotropin-Releasing Hormone (GnRH) but Not for GnRH Receptors in Mouse Mammary Glands

Cited by 14 publications

References 0 publications

Immunohistochemical Localization of Annexin A5 in the Mammary Gland of Rats: Up-Regulation of Expression by Pup Removal

Immunohistochemical Localization of Annexin A5 in the Mammary Gland of Rats: Up-Regulation of Expression by Pup Removal

The genes for gonadotropin-releasing hormone and its receptor are expressed in human breast with fibrocystic disease and cancer

Differential expression of gonadotropin-releasing hormone (GnRH) in pancreas during rat pregnancy

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