Light and scanning electron microscopic study of testosterone‐restored penile papillae in castrated rats

Abstract

Structural changes in various penile tissue from rats with differing circulating androgen levels were analyzed with light and scanning electron microscopy. Adult males were castrated and daily injected for 6 weeks with one of four physiologic amounts of testosterone propionate (TP). Results indicated that epithelium, subepithelial connective tissue, and the papillae protruding from the surface of the glans penis responded, more or less, in a dose-dependent fashion to the steroid. The least androgen-sensitive penile tissue was the epidermal stratum corneum, more sensitive was the maligiphian layer, and more sensitive still was the subepithelium. The penile papillae and their follicles were the most androgen-sensitive tissue. Specifically, the high testosterone, 400 micrograms and 800 micrograms TP, males experienced papillae that were thicker, taller, more densely arranged, and more highly keratinized than the lower testosterone, 100 micrograms and 200 micrograms TP, males. The function of the papillae may be to provide the female with the mechanical stimulation necessary to ensure a proper hormonal milieu for successful impregnation.

The Morphological and Histological Characters of the Male External Genitalia of the House Musk Shrew, Suncus murinus

“…There have been reports of several species that develop penile spines in their external genitalia (Taylor et al ., 1983;Murakami, 1987). Penile spines develop by an androgen dependent manner (Whitsett et al ., 1980;Ninomiya et al ., 1984).…”

“…While ovulation in mice and rats is considered as spontaneous, the penile spines are speculated to play some roles in inducing ovulation in such species. Thus, their development may not simply enable species with spontaneous ovulation to be distinguished from species with post-coital ovulation (Taylor et al ., 1983;Murakami, 1987;Bedford et al ., 1997). It is also reported that penile spines may play some roles in efficient erection and ejaculation for copulation (Dixson, 1991).…”

Adrenal Steroids Uniquely Influence Sexual Motivation Behavior in Male Rats

“…As is likely apparent, the study just described illustrates another important issue in hormone research: dosing. Future studies on the behavioral effects of hormone supplements may benefit from using multiple levels of exposure rather than using the one we have found useful in our lab [21]. …”

“…Males were subcutaneously injected with either 4-A, DHEA, TS, CORT or oil only (vehicle). Hormones were administered as 400 µg steroid/kg of body weight (bwt) [21]. Estradiol benzoate (100 µg/kg bwt) and progesterone (400 µg/kg bwt) were used to induce behavioral estrus in ovariectomized females [27].…”

Copulation induces an acute increase in epididymal sperm numbers in rats

“…The accessory sex glands are stimulated to grow (Hunt, 1968) and their secretory activities are increased (Agmo, 1974). Penile morphology is modified as the papillae on the surface of the glans become uniformly large in response to increased levels of circulating hormone (Taylor, Komitowski & Weiss, 1983a;Taylor, Weiss & Komitowski, 1983c).…”