Effects of food restriction on testis and accessory sex glands in maturing rats

Reduced food consumption and associated lower body weights may occur in subacute toxicity studies. The short-term effects of food restriction (FR) on body and reproductive organ weights, hormones, and testis histology were assessed in Sprague-Dawley rats fed 20% to 36% less (21 g feed/day) than rats fed ad libitum (AL) starting at six, eight, ten, or twelve weeks of age for two or six weeks. Body weight and relative seminal vesicle, ventral prostate, and/or epididymis weights were reduced in rats FR for two or six weeks. Degeneration of stage VII pachytene spermatocytes was seen in rats FR for six weeks when initiated at eight, ten, and twelve weeks of age. Plasma testosterone concentrations were lower in rats FR at ages six to eight weeks, eight to ten weeks, six to twelve weeks, and eight to fourteen weeks. Luteinizing hormone was not statistically different in FR rats compared with AL counterparts. Therefore, duration of lower food intake had a greater impact on spermatogenesis, whereas a younger initial age of lower food intake was more influential on testosterone levels. These interactions are important in the interpretation of subacute toxicology studies employing FR or when test articles lower food consumption relative to AL-fed rats.