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 ...

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 transcription‐polymerase 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 [32P]‐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. © 1997 Wiley‐Liss, Inc.

The GnRHR gene is preferentially expressed in functioning rather than in nonfunctioning gonadotroph adenomas, but no mutations altering the coding region of the gene were found to further substantiate its role in the pathogenesis of gonadotroph tumours.

Farnesylacetone (C18 H30 0) is a male hormone extracted from the androgenic gland of crab, Carcinus maenas. Appropriate enzymatic assays, as well as spectrophotometric studies, indicate that micromolar concentrations of farnesylacetone interact with the electron transport pathway of rat liver mitochondria. By the use of artificial electron donors and electron acceptors, it is shown that farnesylacetone immediately inhibits the electron transfer within complex I (NADH ubiquinone reductase activity) and complex II (succinate ubiquinone reductase activity). It is proposed that farneylacetone could interact with these two complexes of the respiratory chain at the level of the iron-sulfur centers implicated in the dehydrogenase activities. These observations are compared with the results obtained with terpenic molecules which interact with mitochondrial respiration.