Hormonal regulation of sex skin in Macaca nemestrina

Abstract

Artificial menstrual cycles were produced in ovariectomized pig-tailed macaques (Macaca nemestrina) by a sequential estradiol-progesterone regimen. Cyclic changes in sex skin were correlated with systemic levels of estradiol and progesterone. The steroid levels were in the normal range, and the cyclic changes in skin turgor and structure were essentially identical to those found during natural cycles. During the artificial follicular phase, fibroblasts were large and filled with biosynthetic organelles; structures that represented the entire sequence of synthesis, packaging, and secretion of procollagen were found in these hypertrophied cells. In addition, collagen fibers became more dispersed, the amount of hyaluronidase-sensitive material increased, and the stratum corneum became thinner. During the artificial luteal phase, fibroblasts atrophied, collagen fibers became rearranged into bundles, ground substance decreased in amount, and the stratum corneum thickened. The sex skin in spayed, pig-tailed macaques provides a rich source of material in which to study the mechanism of hormone action. It can be driven by estradiol and progesterone to synthesize or degrade collagen and hyaluronic acid, and these end products and their morphological correlates can be monitored by biochemical and ultrastructural techniques.