TESTOSTERONE AND ANDROSTANEDIOL PRODUCTION BY REGENERATING LEYDIG-CELLS IN THE ETHYLENE DIMETHANE SULFONATE-TREATED MATURE RAT

Mature (60–65 day old) male Sprague‐Dawley rats received a single intraperitoneal injection of ethylene dimethane sulphonate (EDS; 100 mg/kg) and were subsequently killed at various times from day 2 to day 40 post‐treatment. Testes were removed from these animals and from age‐matched controls and utilized either for light and electron microscopical analyses or for in‐vitro assessment of Leydig cell function. Interstitial cells were prepared by collagenase digestion and used to measure 125I‐labelled human chorionic gonadotrophin (hCG) binding capacity and androgen production in the presence or absence of hCG or dibutyryl cyclic AMP (dbcAMP). At day 2 after EDS treatment, 125I‐labelled hCG binding capacity was reduced to 10% of control values, while the production of testosterone and 5a‐androstane‐3a, 17β‐diol (adiol) were non‐detectable. Histological observations confirmed the lack of identifiable Leydig cells at day 2–16 after EDS treatment. Between days 24 and 40 post‐treatment, Leydig cell regeneration occurred, as indicated by a rise in 125I‐labelled hCG binding capacity, increased androgen production and the presence of histologically identifiable Leydig cells. A pattern of adiol production similar to that seen in the immature rat during Leydig cell development was observed with peak synthesis occurring at day 30 post‐treatment. Adiol production fell to barely detectable levels by day 36 and remained low at day 40. It is concluded that the steroidogenic pattern of regenerating Leydig cells in the EDS‐treated animal is similar to that of developing Leydig cells in the immature animal. Copyright © 1990, Wiley Blackwell. All rights reserved