Effects of implantation of hypertrophied androgenic glands on sexual characters and physiology of the reproductive system in the female red claw crayfish, Cherax quadricarinatus

The role of the androgenic gland (AG), an organ unique to male Crustacea, i n the development of sex characters and physiology of the reproductive syst em has not been fully documented in the red claw crayfish, Cherax quadricar inatus. To investigate the role of the AG in this species, the effect of im planting hypertrophied AGs into immature female animals was followed. Of th e female animals with AG implants, 91.6% developed male-like propodi, inclu ding the red patch characteristic of males of this species. The development of female secondary sex characteristics such as a wider abdomen, a wider e ndopod, and simple setation was inhibited. At the end of the experiment, th e ovaries of the AG-implanted females contained mostly lipid-stage oocytes, with a small number of oocytes at the early yolk stage. The gonadosomatic index of the AG-implanted females was significantly lower than that of the control (sperm duct-implanted or sham-operated) females, which had mature o ocytes with a well-defined perinuclear zone and yolk globules. An immunohis tochemical test using an antibody developed against a 106-kDa secondary vit ellogenic polypeptide showed only slight immunoreactivity in the oocytes of AG-implanted females compared with abundant immunoreactivity in control ov aries. In the polypeptide profile of the high-density lipoprotein (HDL) fro m the hemolymph of AG-implanted females, the 206- and 79-kDa secondary vite l- logenesis-specific polypeptides were not found, whereas they were presen t in the profile of control females. In contrast, the female-specific 177-k Da polypeptide was present in the polypeptide profile of hemolymph HDL of b oth AG-implanted females and control females. It seems therefore that while secondary sex characters were masculinized under the influence of the impl anted AG, the process of vitellogenesis was suppressed but not fully elimin ated in the AG-implanted females. (C) 2001 Academic Press.