No abstract

\s=b\The existence of hormone receptors on or within neoplastic tissue has potential diagnostic, therapeutic, and prognostic importance. It was the purpose of this study to measure estrogen and progesterone receptors in a large group of patients with head and neck cancer to determine their frequency. Sixty-five patients with head and neck tumors underwent a total of 75 estrogen and 50 progesterone receptor assays. In this group, 87.7% were squamous cell carcinoma. In the estrogen receptor assays, 89.3% (67/75) were negative, 8% (6/75) were borderline, and only 2.7% (2/75) were positive. In the progesterone receptor assays, 78% (39/50) were negative, 22% (11/50) were borderline, and there were no positive results. There were no changes in assays of tissue removed at biopsy v tissue removed during surgery. There was no impact with chemotherapy. In conclusion, head and neck cancers do not appear to possess estrogen or progesterone receptors and can be considered to be hormonally independent.It has now been well established that some breast carcinomas contain receptors for hormones. Other inves¬ tigations have demonstrated that some malignant neoplasms arising in sites other than the breast have hor¬ mone-receptor proteins. The existence of hormone receptors on or within the neoplastic tissue has potential diag¬ nostic, therapeutic, and prognostic importance. The broad implications of this possible hormonal association has generated multiple evaluations to identify which particular tumor types possess these proteins. Indeed, one report1 has noted the presence of estrogen receptors in patients with certain types of head and neck cancer.It was the purpose of this study to measure estrogen and progesterone receptors in a group of patients with head and neck cancer to determine their frequency and thus resolve whether or not these malignant neo¬ plasms are hormonally dependent. MATERIALS AND METHODSEstrogen and progesterone receptors were determined by the multipoint dextran-coated charcoal method. All opera¬ tions in this procedure were carried out at 0 to 4°C. Tumor specimens that were frozen in liquid nitrogen (-196°C) were pulverized, and known amounts of powders were homogenized at 4°C in a PT-10 homogenizer (Brinkmann) (two 10-s bursts) in four volumes of TEDG buffer (lOmM TRIS-HC1,1.5mM ethylenediamine tetraacetic acid [EDTA], ImM dithiothreitol, and 10% glycerol, ph 7.6). Cytosols were prepared by centrifugation of the homogenates for 45 minutes at 105,000 g in an ultracentrifuge at 4°C. Aliquots of the cytosols were then incubated at 4°C for 12 to 16 hours with increasing concentrations of either tritiated (3H)-estradiol-17B (0.15 to 3 nm) or the synthetic progestin (3H-promegestone [R5020, New England Nucle¬ ar]) (0.4 to 8 nm) in the presence (nonspe¬ cific binding) or absence (total binding) of a 200-fold molar excess of unlabeled com¬ petitor. Diethystilbestrol was used in the case of estrogen receptor and R-5020 was

No abstract

Abstract— An adenylate cyclase present in the caudate nucleus of rat brain, which is selectively stimulated by low concentrations of dopamine, and which is believed to mediate dopaminergic synaptic transmission, has been characterized with respect to several properties. The parameters studied included temperature, pH, ATP concentration, Mg/ATP ratio, and metal ion specificity. The effects of other compounds, including EGTA, NaF and several guanosine nucleotides, were also tested on the dopa‐mine‐sensitive adenylate cyclase. In addition, the subcellular distribution of the enzyme was studied. The highest specific activity was found in subcellular fractions enriched in nerve endings. A half‐maximal increase in the activity of the enzyme in a subcellular fraction occurred in the presence of 4 × 10−6 M dopamine. Fluphenazine, a dopamine antagonist, competitively inhibited the activity of the enzyme in this fraction, with a calculated inhibition constant (Ki) of 8 × 10−9M.