Biomaterial Database

Role of prolactin in growth of the rat mammary tumor MTW9. 1991

M Platica, and J Doody, and J P Mandeli, and V P Hollander

Dept. of Surgery, Mount Sinai School of Medicine, New York, NY.

The growth of MTW9 mammary tumors exhibits different degrees of responsiveness to ovariectomy, ranging from sensitivity to resistance. This range of response is a function of time elapsing from tumor inoculation until performance of ovariectomy provided that prolactin (PRL) level is kept continuously high. In vivo studies showed that the MTW9 tumors developed by chronic administration of spiramide were sensitive to ovariectomy by 60 days, but they became resistant to ovariectomy by 100 days. However, when spiramide treatment was discontinued after tumor appearance, the tumors were still sensitive to ovariectomy by 100 days. Chromatofocusing (CF) profile of cytosolic estrogen receptors (ER) correlated with the responsiveness to ovariectomy. A 2-peak profile for tumors sensitive to ovariectomy, and only a one-peak profile for tumors resistant to ovariectomy, were seen. Although the prolactin level in rats bearing the tumors was higher than in the normal rats, no correlation between the PRL level and the change in CF profile of ER over time was seen. Also, these changes could not be correlated with the tumor size. In vitro studies showed that incubation of cytosolic ER from a sensitive tumor (2 peaks) with PRL led to a CF profile with only one peak, characteristic of a resistant tumor. Leupeptin, molybdate and phenylmethylsulfonylfluoride (PMSF) could not prevent this transition. The effect was not reproduced by incubation with growth hormone or progesterone. Our data suggest that PRL, either directly or through intermediates, may play a role in changing the response to hormonal therapy of the mammary tumor MTW9.

UI	MeSH Term	Description	Entries
D008325	Mammary Neoplasms, Experimental	Experimentally induced mammary neoplasms in animals to provide a model for studying human BREAST NEOPLASMS.	Experimental Mammary Neoplasms,Neoplasms, Experimental Mammary,Experimental Mammary Neoplasm,Mammary Neoplasm, Experimental,Neoplasm, Experimental Mammary
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
D011388	Prolactin	A lactogenic hormone secreted by the adenohypophysis (PITUITARY GLAND, ANTERIOR). It is a polypeptide of approximately 23 kD. Besides its major action on lactation, in some species prolactin exerts effects on reproduction, maternal behavior, fat metabolism, immunomodulation and osmoregulation. Prolactin receptors are present in the mammary gland, hypothalamus, liver, ovary, testis, and prostate.	Lactogenic Hormone, Pituitary,Mammotropic Hormone, Pituitary,Mammotropin,PRL (Prolactin),Hormone, Pituitary Lactogenic,Hormone, Pituitary Mammotropic,Pituitary Lactogenic Hormone,Pituitary Mammotropic Hormone
D011960	Receptors, Estrogen	Cytoplasmic proteins that bind estrogens and migrate to the nucleus where they regulate DNA transcription. Evaluation of the state of estrogen receptors in breast cancer patients has become clinically important.	Estrogen Receptor,Estrogen Receptors,Estrogen Nuclear Receptor,Estrogen Receptor Type I,Estrogen Receptor Type II,Estrogen Receptors Type I,Estrogen Receptors Type II,Receptor, Estrogen Nuclear,Receptors, Estrogen, Type I,Receptors, Estrogen, Type II,Nuclear Receptor, Estrogen,Receptor, Estrogen
D002455	Cell Division	The fission of a CELL. It includes CYTOKINESIS, when the CYTOPLASM of a cell is divided, and CELL NUCLEUS DIVISION.	M Phase,Cell Division Phase,Cell Divisions,Division Phase, Cell,Division, Cell,Divisions, Cell,M Phases,Phase, Cell Division,Phase, M,Phases, M
D003600	Cytosol	Intracellular fluid from the cytoplasm after removal of ORGANELLES and other insoluble cytoplasmic components.	Cytosols
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
D013141	Spiro Compounds	Cyclic compounds that include two rings which share a single atom (usually a carbon). The simplest example of this type of compound is Spiro[2.2]pentane, which looks like a bow tie.	Compounds, Spiro