Steroids in the male reproductive system of the ampullariid snail Pomacea canaliculata

GAMARRA-LUQUES, C.; CASTRO-VAZQUEZ, A.

San Luis

Congreso; XXII Reunión Anual de la Sociedad de Biología de Cuyo; 2004

Sociedad de Biología de Cuyo

Steroids in the male reproductive system of the ampullariid snail Pomacea canaliculata Gamarra-Luques, C., Castro-Vazquez, A.  Lab. of Physiology, IHEM, UNCuyo-CONICET, C. de Correo  33, 5500 Mendoza. E-mail: cgamarra@fcm.uncu.edu.ar Reports on the existence of steroid hormones and their receptors in mollusks are rather scanty. In P. canaliculata, only testosterone in the testis, and estradiol and progesterone in the ovary and uterine gland have been reported (although the methodology used was not mentioned). We here determined the concentration (mg/g tissue) of free and sterified cholesterol through thin layer chromatography and colorimetry in the midgut gland, testis, prostate, penile complex, and the proximal and distal parts of the penile sheath of P. canaliculata. Also, the concentration of progesterone, androstenedione, testosterone and estradiol, using specific and sensitive radioimmunoassays. The midgut gland showed the highest (0.27) sterified/free cholesterol ratio, while the other tissues showed sterified/free ratios of 0.05 or less, which would suggest that only the midgut gland would be able to accumulate cholesterol for steroid synthesis. We were not able to detect either testosterone or estradiol in any case. No other steroids were detected in testis either, while low but detectable mean progesterone levels (18-46 ng/100 mg tissue) could be shown in the other studied tissues, except the distal part of the penile sheath. Androstenedione levels (230-752 pg/100 mg tissue) were detected in all studied tissues except the testis. We conclude that (1) the midgut gland may be the main steroid producing organ in this snail; (2) both progesterone and androstenedione may be accomplishing the androtrophic function; and (3) that these hormones may also originate in the accessory male organs (i.e., not in the testis), where they would act locally.