Changes of ovarian interstitial cell hormone receptors and behavior of resident mesenchymal cells in developing and adult rats with steroid-induced sterility Antonin Bukovsky a, *, Maria E. Ayala b , Roberto Dominguez b , Jeffrey A. Keenan a , Jay Wimalasena a , Robert F. Elder a , Michael R. Caudle a a Laboratory for Development, Differentiation and Cancer, Department of Obstetrics and Gynecology, The University of Tennessee Graduate School of Medicine, 1924 Alcoa Highway, Knoxville, TN 37920, USA b Laboratory of Biology of Reproduction, Facultad de Estudios Profesionales Zaragoza, UNAM, Mexico D.F., Mexico Received 19 March 2001; received in revised form 5 July 2001; accepted 17 July 2001 Abstract In the present paper, we report that injection of testosterone propionate (500 g) during the critical window of rat development (postnatal day 5) induces temporary appearance of aged interstitial cells in developing ovaries (days 7 and 10). Aged interstitial cells showed large size ( 12 m), enhanced androgen receptor (AR) and low estrogen (ER) and luteinizing hormone receptor (LHR) expression. Although normal mature interstitial cells (large size and strong ER and LHR expression) appeared later (day 14), and ovaries of androgenized rats were similar to normal ovaries between days 14 and 35, ovaries of adult androgenized females showed only aged and no mature interstitial cells. Androgenization on day 10 caused the development of aged interstitial cells on day 14, but adult ovaries were normal. Long lasting postnatal estrogenization (estradiol dipropionate for four postnatal weeks) caused in developing and adult ovaries a lack of interstitial cell development beyond the immature state. Immature interstitial cells were characterized by a small size ( 7 m) and a lack of AR, ER and LHR expression. Because the critical window for steroid-induced sterility coincides with the termination of immune adaptation, we also investigated distribution of mesenchymal cells (Thy-1 mast cells and pericytes, ED1 monocyte-derived cells, CD8 T cells, and cells expressing OX-62 of dendritic cells) in developing and adult ovaries. Developing ovaries of normal, androgenized and estrogenized females were populated by similar mesenchymal cells, regardless of differences in the state of differentiation of interstitial cells. However, mesenchymal cells in adult ovaries showed distinct behavior. In normal adult ovaries, differentiation of mature interstitial cells was accompanied by differentiation of mesenchymal cells. Aged interstitial cells in ovaries of androgenized rats showed precipitous degeneration of resident mesenchymal cells. Immature interstitial cells in ovaries of estrogenized rats showed a lack of differentiation of resident mesenchymal cells. These observations indicate that an alteration of interstitial cell differentiation during immune adaptation toward the aged phenotype results in precipitous degeneration of resident mesenchymal cells and premature aging of ovaries in adult rats, and alteration toward immature phenotype results in a lack of differentiation of mesenchymal cells and permanent immaturity of ovaries in adult females. © 2002 Elsevier Science Inc. All rights reserved. Keywords: Steroid-induced sterility; Androgens; Estrogens; Ontogeny; Immune adaptation; Hormone receptors; Cellular aging; Cellular immaturity 1. Introduction 1.1. Steroid-induced sterility and critical window of development Administration of androgens to female rats during the first week of postnatal life has been shown to induce anovu- latory sterility. Androgenized females exhibit permanent cornification of the vaginal epithelium, and their ovaries contain follicular cysts. Postnatal treatment with multiple doses, or single injection of testosterone propionate ( 50 g) during the first week of postnatal life, produce similar results [1– 4]. After the physiological critical period (post- natal days 1– 6) has elapsed, the incidence of androgen- induced anovulation diminishes, and is zero at postnatal day 10 [4]. Injection of a large dose of testosterone propionate to * Corresponding author. Tel.: +1-865-544-8969; fax: +1-865-544- 6863. E-mail address: buko@utk.edu (A. Bukovsky). Steroids 67 (2002) 277–289 0039-128X/02/$ – see front matter © 2002 Elsevier Science Inc. All rights reserved. PII: S0039-128X(01)00159-3