title: Endocrinological changes before and after removal of the granulosa theca cell tumor (GTCT) affected ovary in 6 mares.
abstract: To clarify the endocrinological characteristics of the mares with granulosa theca cell tumor (GTCT), peripheral plasma samples from the 6 mares affected with GTCT were collected before and after the surgical removal of the affected ovary. Concentrations of testosterone (T), follicle stimulating hormone (FSH), luteinizing hormone (LH), immunoreactive-inhibin (ir-INH), progesterone (P) and estradiol-17beta (E(2)) in the plasma samples were measured by radioimmunoassay. Before removal of GTCT in all cases, the concentrations of T were significantly higher than those of normal mares at the breeding and non-breeding seasons, whereas plasma concentrations of FSH, LH, ir-INH, P and E(2) were lower. After surgical removal of the affected ovary, the circulatory concentrations of T was declined, but the concentrations of other hormones were constantly low as compared with those of normal mares. The present study suggests that 1) the source of higher T may be due to the abnormal follicles in ovary of GTCT, 2) in the case of GTCT the elevated level of T is observed due to the lack of aromatase, and 3) the high level of T is a typical characteristics for GTCT in mares. It is also suggested 4) due to the elevated levels of T the concentrations of gonadotropins may be suppressed.
authors.affiliation: Department of Veterinary Medicine, Faculty of Agriculture, Iwate University, Morioka, Japan.
authors.forename: Shafiqul
authors.initials: S
authors.lastname: Hoque
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Senba
authors.forename: Nobuo
authors.initials: N
authors.lastname: Tsunoda
authors.forename: Refaat Ibrahim
authors.initials: RI
authors.lastname: Derar
authors.forename: Gen
authors.initials: G
authors.lastname: Watanabe
authors.forename: Kazuyoshi
authors.initials: K
authors.lastname: Taya
authors.forename: Takeshi
authors.initials: T
authors.lastname: Osawa
authors.forename: Yoh-Ichi
authors.initials: Y
authors.lastname: Miyake
mesh_terms: D000818:Animals; D004958:Estradiol / Q000097:blood; D005260:Female; D005640:Follicle Stimulating Hormone / Q000097:blood; D006728:Hormones / Q000097:blood*; D006734:Horse Diseases / Q000097:blood / Q000601:surgery*; D006736:Horses; D007986:Luteinizing Hormone / Q000097:blood; D011374:Progesterone / Q000097:blood; D013798:Thecoma / Q000097:blood / Q000601:surgery / Q000662:veterinary*; D013997:Time Factors
chemical_list: D006728:Hormones; D011374:Progesterone; D004958:Estradiol; D007986:Luteinizing Hormone; D005640:Follicle Stimulating Hormone