Seasonal Changes in Urinary Prostate‐Specific Antigenic Activity in Male Japanese Macaques (Macaca fuscaa fuscata)

Abstract

Prostate-specific antigen (PSA) is usually detected in male adult urine and semen according to the Tanner stage development of males from birth to adolescence. To further study the pituitary-testicular axis in males, we determined urinary PSA levels in primates. Urinary PSA was detected with the use of anti-human PSA monoclonal antibody in male adult Japanese macaques (Macaca fuscaa fuscata) of seasonal breeding status. PSA activity in aseasonal animals (crab-eating macaques, Macaca fascisularis) did not change throughout the year; however, alterations in PSA activity were observed in Japanese macaques during breeding season, with the highest levels observed between October and January, the lowest levels between January and June, and a gradual increase in PSA activity observed from August until October. Although primate urinary PSA produces 2 polypeptide bands of approximately 55 and 33 kd, in addition to a band corresponding to human urinary PSA, the 33-kd polypeptide band was less pronounced during nonbreeding season in Japanese macaques. Urinary testosterone (T) levels in seasonally breeding animals (Japanese macaques) changed in parallel with urinary PSA levels. When urinary PSA and T levels were compared among animals during the breeding season (from October to February) and the nonbreeding season (from March to September), significantly increased PSA and T levels were observed during the breeding season. Furthermore, PSA and T levels in a monkey housed in a cage placed between 2 female cages were elevated compared with other monkeys. Increased PSA activity was observed concurrent with menstrual blood loss in females. These results suggest a link between PSA activity and testosterone levels, which could be influenced by changes in the female menstrual cycle.