Beth S. Schachter

Distribution and Partial Characterization of Immunoreactive Prolactin in the Rat Brain

Immunoreactive (IR) prolactin was localized immunocytochemically in cell bodies in the mediobasal hypothalamus and in fibers in many regions of the rat brain. The cell bodies were found in the arcuate nuclei and the adjacent areas ventral to the ventromedial nuclei. Fiber projections extended rostrally to and/or through the anterior hypothalamus, preoptic area, nucleus accumbens, septum, diagonal bands of Broca, caudate-putamen, frontal cortex and accessory olfactory bulb; laterally to the amygdala, especially the central nucleus and some parts of the medial nucleus; caudally to and/or through the midbrain central gray, reticular formation, parabrachial region, and several portions of the lower brain stem and spinal cord extending to sacral levels. The system appears to be essentially identical to that containing proopiomelanocortin (POMC) and its processed peptides, as shown by double immunocytochemistry. Preabsorption of the antiprolactin antiserum with either prolactin or the 16,000-dalton N-terminus of POMC eliminated immunoreactivity in the brain. Preabsorption with other POMC-derived peptides, including beta-lipotropic hormone, beta-endorphin, met-enkephalin, adrenocorticotrophic hormone (1-24), corticotropin-like intermediate lobe peptide, alpha- and gamma-melanocyte-stimulating hormones and an octapeptide region of the N-terminus of POMC bearing some homology with prolactin, did not eliminate immunoreactivity in the brain. Similarly, preabsorption with growth hormone, luteinizing hormone, follicle-stimulating hormone, motilin or fetuin did not eliminate immunoreactivity in the brain. The antiprolactin antiserum also recognized all cells in the intermediate lobe and a subset of cells in the anterior lobe of the Snell dwarf mouse pituitary. This immunoreactivity was eliminated by preabsorption of the antiserum with prolactin or with the 16,000-dalton N-terminus of POMC. These results suggest that IR prolactin in the brain may be related to the N-terminus of POMC. Additional results based on one- and two-dimensional gel electrophoresis and immunoblotting indicate that the antiprolactin antiserum used in the majority of the immunocytochemical studies recognized a number of proteins.

Association between pregnancy-induced hypertension and asthma during pregnancy

OBJECTIVE Pregnancy-induced hypertension is an important cause of maternal mortality, intrauterine growth retardation, and perinatal mortality. We examined the relationship between pregnancy-induced hypertension and asthma. STUDY DESIGN The study population consisted of 24,115 women without a history of chronic systemic hypertension who were delivered of live born and stillborn infants at Mount Sinai Medical Center between January 1987 and December 1991. Pregnancy-induced hypertension was defined as blood pressure of at least 140/90 mm Hg or an increase of > or = 30 mm Hg in systolic pressure or > or = 15 mm Hg in diastolic pressure. RESULTS There was a significant association between pregnancy-induced hypertension and asthma during pregnancy (chi 2 = 17.86, p < 0.001). In addition, there was a significant upward trend in the incidence of asthma during pregnancy in women without, with moderate, and with severe pregnancy-induced hypertension (Mantel-Haenszel chi 2 = 11.8, p = 0.001). Logistic regression analysis demonstrated that the association between pregnancy-induced hypertension and asthma during pregnancy persisted after adjustment for the confounding factors of race or ethnicity, maternal age, parity, and prepregnancy weight (adjusted odds ratio 2.52, 95% confidence interval 1.47 to 4.35, p = 0.0008). An association between pregnancy-induced hypertension and a history of asthma was also found (chi 2 = 11.2, p = 0.001). However, after adjustment for potential confounders, this association failed to achieve statistical significance (adjusted odds ratio 1.2, 95% confidence interval 0.97 to 1.53, p = 0.083). CONCLUSION Both pregnancy-induced hypertension and asthma might be caused by a third factor affecting smooth muscle reactivity.

Incidence of an estrogen receptor polymorphism in breast cancer patients

SummaryWe previously identified a polymorphism in the human estrogen receptor (ER) gene, within the coding region for the proteins amino terminal B-domain. In estrogen receptor-positive (ER+) breast tumors, the variant allele was preferentially associated with lower levels of ER, and was clinically correlated with frequent spontaneous abortions. DNA sequencing revealed a point mutation that changes codon 86 from Ala to Val and a silent mutation in codon 87. Because we initially detected the variant allele by analyzing RNA, only those tissues in which the ER gene is actively expressed were suitable for genotype analysis. We now describe an assay that uses genomic DNA as the substrate for determining the ER B genotype; DNA containing the polymorphic region of the ER gene is amplified by the polymerase chain reaction, then the amplified DNA is hybridized with radiolabeled oligonucleotide probes complementary to the wild type and variant ER alleles. This method allowed us to determine the ER B genotype of women with ER+ and ER− tumors, starting with minute amounts of DNA from frozen or paraffin embedded tissues. ER B genotyping was also performed on women without breast cancer using DNA extracted from blood cells. The combined results from analyses of RNA and DNA from 300 breast cancer patients showed that 12% were heterozygotes. In the ER+ group (n=183), 11.5% carried the variant gene compared to 12.8% in the ER-negative group (n=117) (χ2=0.11; df=1; p>0.25). No link to tumor histology could be established. Preliminary data on DNA from blood of healthy women over the age of 50 (n=64) yielded a slightly lower ER B-variant frequency (9.4%); this frequency was not significantly different than that in the breast cancer groups. Thus, while the variant ER allele is associated with low ER levels in ER positive breast tumors, its frequency is not different in the ER+ and ER− tumor groups and may be unrelated to breast cancer development.

An estrogen receptor genetic polymorphism and the risk of primary and secondary recurrent spontaneous abortion

OBJECTIVE A case-control study was undertaken to assess the association between an estrogen receptor gene variant and the risk of recurrent spontaneous abortions. STUDY DESIGN The frequency of the estrogen receptor gene variant in blood lymphocyte deoxyribonucleic acid and other selected maternal characteristics was compared among 60 primary recurrent aborters, 61 secondary recurrent aborters, and 43 women who had had at least two live births but no spontaneous abortions. RESULTS No association was evident between the estrogen receptor gene variant and the risk of either primary or secondary recurrent abortion. There were data suggesting that primary recurrent aborters in particular were more likely to report a family history of recurrent abortion and a family history of breast cancer. CONCLUSIONS These findings indicate that the estrogen receptor polymorphism is not a genetic marker for recurrent spontaneous abortions. Therefore, as suggested by previous investigations, this polymorphism appears to be a marker for breast cancer risk only among the subgroups who have had a history of repeated abortions.

Antagonism between estrogens and androgens on gcdfp-15 gene expression in ZR-75-1 cells and correlation between GCDFP-15 and estrogen as well as progesterone receptor expression in human breast cancer☆

The androgen dihydrotestosterone (DHT) caused a maximal 65% inhibition of proliferation of the human breast cancer cells ZR-75-1 after a 10-day incubation period. The same treatment, on the other hand, stimulated by 25-fold the secretion of the breast marker protein GCDFP-15 (gross cystic disease fluid protein-15). The stimulatory effect of DHT on GCDFP-15 mRNA accumulation was already significant (1.6-fold, P less than 0.01) after a 12 h exposure and reached a maximal 25-fold increase after a 12-day incubation period. On the other hand, a 2-day exposure to 1 nM 17 beta-estradiol (E2) alone decreased by 60% GCDFP-15 mRNA levels while it completely blocked the 2.5-fold stimulation of GCDFP-15 secretion induced by concomitant incubation with DHT. Furthermore, a 10-day incubation with E2 increased by 4-fold the proliferation of ZR-75-1 cells whereas such treatment decreased by about 85% both GCDFP-15 mRNA accumulation and the secretion of the glycoprotein. The presence of GCDFP-15 mRNA in human breast cancer samples was restricted to estrogen receptor positive tumors and was significantly correlated with progesterone receptor expression.

Xenobiotic metabolism genes and the risk of recurrent spontaneous abortion.

We examined the relation between spontaneous abortion and polymorphisms in two genes, glutathione S-transferase (GSTM1) and N-acetyltransferase (NAT2), which are involved in the metabolism of xenobiotics. In a case-control study of 29 women, we found that, among women with the GSTM1 null genotype, the odds ratio (OR) was 3.1 [95% confidence interval (CI) = 1.3-7.0]. There was less evidence of a relation with NAT2 [Mantel-Haenszel adjusted OR (ORMH) = 1.4; 95% CI = 0.45-4.3]. We sought to replicate the GSTM1 finding in an independent case-control study from New York involving 89 cases. We found an inverse association (OR = 0.8; 95% CI = 0.4-2.4). Taken together, these data provide little evidence of an association between GSTM1 or NAT2 genotype and risk of spontaneous abortion.

Regulation of HLA-DR Gene Expression in Cultured Human Thyroid Cells: A Role for Lectin, Gamma Interferon, and Cyclosporine

HLA Class II antigens (DR, DQ, and DP) are expressed primarily on the surface of the lymphocytes (B and activated T cells) and cells of the monocyte-macrophage lineage, but may also be expressed in a variety of tissues, in particular those which contain immune infiltration with local release of lymphokines (i.e., gamma interferon), which are potent inducers of Class II antigen expression. Immunofluorescence studies have demonstrated that although normal human thyroid tissue is negative for DR antigen, HLA-DR antigen is present in human thyroid cells in cases of autoimmune thyroid disease such as Graves’ hyperthyroidism (1,2). Furthermore, Class II HLA-DR antigen in normal thyroid cells is detected after exposure in vitro to lectin or gamma-interferon (1,3). Since Class II antigens are important in T cell amplification, antigen presentation and self-recognition (4), such quantitative differences in DR antigen expression in the thyroid may be involved in the control of thyroid autoimmunity. In order to further elucidate the role of Class II antigens in thyroid immunoregulation, we have studied HLA-DR antigen gene expression in a variety of cultured human thyroid cells.