Regulation of dopamine receptors in the MtT/W15 transplantable pituitary tumor by estrogen. 1986

R V Lloyd, and K L Fields

We investigated the effects of estrogens on the regulation of dopamine receptors in the MtT/W15 transplantable rat pituitary tumor. Diethylstilbestrol (DES) and 17beta-estradiol treatment in female rats significantly decreased the number of dopamine binding sites (B max) from 85 +/- 3.9 fmol/mg protein in untreated rats to 9.2 +/- 1.2 and 8.2 +/- 2.8 fmol/mg protein in DES and 17beta-estradiol-treated rats, respectively, while the binding affinities (Kd) did not change significantly. Testosterone treatment did not change the B max, while ovariectomy resulted in a significant increase in the B max (146.3 +/- 6.7 fmol/mg protein). The effects of DES on the B max were reversible, since removal of the DES for one week before sacrificing the animals led to a marked increase in the B max (54.9 +/- 3.1 fmol/mg protein). Pituitaries from normal female rats treated with DES for 6 and 9 weeks had a significant decrease in the B max. These results show that the number of dopamine binding sites in the membranes of MtT/W15 tumors is decreased by estrogen treatment and that this effect is reversible after removal of the estrogenic stimulus.

UI MeSH Term Description Entries
D007700 Kinetics The rate dynamics in chemical or physical systems.
D010052 Ovariectomy The surgical removal of one or both ovaries. Castration, Female,Oophorectomy,Bilateral Ovariectomy,Bilateral Ovariectomies,Castrations, Female,Female Castration,Female Castrations,Oophorectomies,Ovariectomies,Ovariectomies, Bilateral,Ovariectomy, Bilateral
D010911 Pituitary Neoplasms Neoplasms which arise from or metastasize to the PITUITARY GLAND. The majority of pituitary neoplasms are adenomas, which are divided into non-secreting and secreting forms. Hormone producing forms are further classified by the type of hormone they secrete. Pituitary adenomas may also be characterized by their staining properties (see ADENOMA, BASOPHIL; ADENOMA, ACIDOPHIL; and ADENOMA, CHROMOPHOBE). Pituitary tumors may compress adjacent structures, including the HYPOTHALAMUS, several CRANIAL NERVES, and the OPTIC CHIASM. Chiasmal compression may result in bitemporal HEMIANOPSIA. Pituitary Cancer,Cancer of Pituitary,Cancer of the Pituitary,Pituitary Adenoma,Pituitary Carcinoma,Pituitary Tumors,Adenoma, Pituitary,Adenomas, Pituitary,Cancer, Pituitary,Cancers, Pituitary,Carcinoma, Pituitary,Carcinomas, Pituitary,Neoplasm, Pituitary,Neoplasms, Pituitary,Pituitary Adenomas,Pituitary Cancers,Pituitary Carcinomas,Pituitary Neoplasm,Pituitary Tumor,Tumor, Pituitary,Tumors, Pituitary
D011920 Rats, Inbred WF An inbred strain of rat that is used in BIOMEDICAL RESEARCH. Rats, Inbred Wistar Furth,Rats, Wistar Furth,Rats, WF,Inbred WF Rat,Inbred WF Rats,Rat, Inbred WF,Rat, WF,WF Rat,WF Rat, Inbred,WF Rats,WF Rats, Inbred,Wistar Furth Rats
D011954 Receptors, Dopamine Cell-surface proteins that bind dopamine with high affinity and trigger intracellular changes influencing the behavior of cells. Dopamine Receptors,Dopamine Receptor,Receptor, Dopamine
D002460 Cell Line Established cell cultures that have the potential to propagate indefinitely. Cell Lines,Line, Cell,Lines, Cell
D004054 Diethylstilbestrol A synthetic nonsteroidal estrogen used in the treatment of menopausal and postmenopausal disorders. It was also used formerly as a growth promoter in animals. According to the Fourth Annual Report on Carcinogens (NTP 85-002, 1985), diethylstilbestrol has been listed as a known carcinogen. (Merck, 11th ed) Stilbestrol,Agostilben,Apstil,Diethylstilbestrol, (Z)-Isomer,Diethylstilbestrol, Disodium Salt,Distilbène,Stilbene Estrogen,Tampovagan,Estrogen, Stilbene
D004958 Estradiol The 17-beta-isomer of estradiol, an aromatized C18 steroid with hydroxyl group at 3-beta- and 17-beta-position. Estradiol-17-beta is the most potent form of mammalian estrogenic steroids. 17 beta-Estradiol,Estradiol-17 beta,Oestradiol,17 beta-Oestradiol,Aerodiol,Delestrogen,Estrace,Estraderm TTS,Estradiol Anhydrous,Estradiol Hemihydrate,Estradiol Hemihydrate, (17 alpha)-Isomer,Estradiol Monohydrate,Estradiol Valerate,Estradiol Valeriante,Estradiol, (+-)-Isomer,Estradiol, (-)-Isomer,Estradiol, (16 alpha,17 alpha)-Isomer,Estradiol, (16 alpha,17 beta)-Isomer,Estradiol, (17-alpha)-Isomer,Estradiol, (8 alpha,17 beta)-(+-)-Isomer,Estradiol, (8 alpha,17 beta)-Isomer,Estradiol, (9 beta,17 alpha)-Isomer,Estradiol, (9 beta,17 beta)-Isomer,Estradiol, Monosodium Salt,Estradiol, Sodium Salt,Estradiol-17 alpha,Estradiol-17beta,Ovocyclin,Progynon-Depot,Progynova,Vivelle,17 beta Estradiol,17 beta Oestradiol,Estradiol 17 alpha,Estradiol 17 beta,Estradiol 17beta,Progynon Depot
D005260 Female Females
D000818 Animals Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA. Animal,Metazoa,Animalia

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