title: Studies on the origin of ovarian interstitial tissue and the incidence of endometrial hyperplasia in domestic and feral cats.
abstract: Ovarian interstitial cells (OICs) are a common feature of mammalian gonads but little is understood concerning their origin or functional significance. This study investigated the development and steroidogenic potential of OIC in feral and colony-reared feline queens. Reproductive tracts, collected from a total of 50 female colony and feral cats, were fixed and analyzed by morphometry. Ovarian sections were also immuno-stained for the expression of the steroidogenic enzymes 17alpha-hydroxylase/17,20 lyase cytochrome P450 (P450c17), 3beta-hydroxysteroid dehydrogenase/Delta5-Delta4 isomerase (3beta-HSD), and aromatase. These findings were related to serum estradiol and testosterone concentrations and to the degree of existing cystic endometrial hyperplasia (CEH). Feral cats had three times as many OICs as colony-reared queens (2713 +/- 855 vs 744 +/- 494 cells/mm(2), P < 0.01). These cells were lipid laden and expressed both P450c17 and 3beta-HSD at levels that were higher than those seen in the theca interna of adjacent follicles. Aromatase expression was undetectable. The pattern of enzyme expression was consistent with development of interstitial tissue from atretic follicles and the potential for continued steroid secretion during the anestrum. The incidence of CEH was higher in older (>5 years old; 88.2%) than in younger (2-4 years; 30%) colony queens (P < 0. 01), whereas no such disease was evident in any of the feral cats. Estradiol levels were higher in colony-reared than in feral cats, but testosterone levels were not different. These data are consistent with the transformation of the theca interna of atretic follicles in cats into OICs that retain a similar, or even enhanced, steroidogenic phenotype. Colony-reared cats exhibit a predisposition to CEH compared with feral queens that is associated with elevated serum estradiol concentrations. Whether or not OICs somehow prevent the development of uterine disease or otherwise reflect a gonadal response to reduced negative feedback on the hypothalamic-pituitary axis remains to be determined.
authors.affiliation: School of Veterinary Medicine, Universidad Complutense de Madrid, Madrid, 28040, Spain.
authors.forename: J F
authors.initials: JF
authors.lastname: Perez
authors.forename: A J
authors.initials: AJ
authors.lastname: Conley
authors.forename: J A
authors.initials: JA
authors.lastname: Dieter
authors.forename: J
authors.initials: J
authors.lastname: Sanz-Ortega
authors.forename: B L
authors.initials: BL
authors.lastname: Lasley
mesh_terms: D015096:3-Hydroxysteroid Dehydrogenases / Q000032:analysis; D000818:Animals; D000835:Animals, Wild; D001141:Aromatase / Q000032:analysis; D002371:Cat Diseases / Q000453:epidemiology* / Q000473:pathology; D002415:Cats; D004714:Endometrial Hyperplasia / Q000453:epidemiology / Q000473:pathology / Q000662:veterinary*; D004958:Estradiol / Q000097:blood; D005260:Female; D007150:Immunohistochemistry; D010053:Ovary / Q000201:enzymology / Q000473:pathology*; D013254:Steroid 17-alpha-Hydroxylase / Q000032:analysis; D013739:Testosterone / Q000097:blood; D014599:Uterus / Q000473:pathology
chemical_list: D013739:Testosterone; D004958:Estradiol; D015096:3-Hydroxysteroid Dehydrogenases; D001141:Aromatase; D013254:Steroid 17-alpha-Hydroxylase