CHEMICAL SYMPATHECTOMY BLOCKS ANDROGEN BIOSYNTHESIS DURING PREPUBERTY

Twenty-one-day old male Wistar rats were injected subcutaneously with guanethidine (GUA) at doses of 5 and 10 mg kg(-1) day(-1) for 20 days. Animals were sacrificed by decapitation during the prepubertal (41 da ys of age) and early-pubertal (51 days of age) periods of sexual devel opment. The testes were collected, frozen in liquid N-2 and stored at -70 degrees C until determination of testicular progesterone (P): andr ostenedione (A) and testosterone (T). Higher levels of P (2.18 +/- 0.2 4 ng/g. control = 1.24 +/- 0.16 ng/g) associated with decreased levels of androgens (A = 0.26 +/- 0.06 ng/g and T = 2.05 +/- 0.19 ng/g; cont rol = 1.86 +/- 0.76 ng/g and 8.48 +/- 1.16 ng/g, respectively) were ob served in 10 mg GUA-treated rats of prepubertal age, while only P leve ls (3.12 +/- 0.51 ng/g control = 1.73 +/- 0.27 ng/g) were increased in rats of early pubertal age. It is important to note that in 41-day ol d male rats both 5 and 10 mg were effective in decreasing testicular c oncentration of testosterone. These results suggest that the sympathet ic innervation of the testis is involved in the modulation of androgen biosynthesis, acting through a selective step in the steroid biochemi cal pathway during the pubertal process and that under the conditions employed the blockage in androgen biosynthesis in the prepubertal stag e of sexual maturation is dependent on the dose of GUA.