EFFECTS OF CASTRATION ON EARLY POSTNATAL-DEVELOPMENT OF MALE ACCESSORY SEX GLANDS IN THE DOMESTIC PIG

In the neonatal pig there is a remarkable production of steroids by th e testes for the first few weeks after birth. Several androgens and es trogens reach a peak at about one month of age, In order to gain an un derstanding of the significance of this early steroid secretion we exa mined the effect on accessory sex glands of removal of the testes befo re the peak: in these compounds would have occurred. Pigs were castrat ed (n = 38) at 2-3 weeks of age, with littermates serving as intact co ntrols (n = 33). Animals were killed at ages ranging from 4-12 weeks. Blood samples were taken and both bulbourethral (BU) and vesicular gla nds (VG) were removed, as well as the testes of intact males. Organ pa irs were weighed and samples fixed for histological examination. Plasm a samples were stored at -20 degrees C until assayed, without extracti on, for testosterone, dehydroepiandrosterone sulfate (DHEAS) and estro ne sulfate (E1S) by radioimmunoassay. Of the hormones measured, plasma DHEAS concentrations were highest, but variable over the time period (304.2 and 75.6 nmol/l; 87.7 and 21.8 ng/ml at 5 and 12 weeks respecti vely). E1S declined steadily from 76.6 to 5.8 nmol/l (20.7 to 1.56 ng/ ml). Testosterone levels were lowest but rose from 2.67 to 9.54 nmol/l (0.77 to 2.75 ng/ml). No steroids were clearly detectable in samples from castrated males. Testes weights (wt) increased fourfold, as did b ody wt for both intact and castrate males. Both BU and VG showed absol ute increases in wt (3.5x and 5x respectively) in intact males, and ea ch was about 2.8x greater than in castrates (mg/kg body wt). Histologi cal sections were markedly distinctive for both BU and VG between inta ct and castrate animals, and a lack of developmental changes in both g lands was noted in the castrates. Our findings provide clear evidence of an influence of the testes on accessory sex glands in the early pos tnatal life of the pig.