Metabolism of oestrone and oestradiol-17 beta to conjugated steroids by the accessory sex glands of the male pig

Oestrogens are secreted in large amounts by boar testes and are known to ha ve a synergistic effect with testosterone on the production of large volume s of seminal plasma. Thus, oestrogens Flay a role in, regulating the large accessory sex glands in the boar. Since testosterone metabolites (e.g. 5 al pha-dihydrotestosterone) account for much of its action in target tissues w e have looked at the metabolism of oestrogens in the accessory sex glands o f the male pig. Tissues from seminal vesicles and bulbourethral glands of 6 -week-old castrate and intact males, and 12-week-old castrate animals, were incubated with H-3-labelled oestrone and oestradiol-17 beta. Aliquots of s pent culture medium and of methanolic tissue extracts were taken to measure radioactivity, prior to separation of unconjugated and conjugated steroids on Waters C-18 Sep-Pak cartridges. About one-third of the radioactivity ap peared as conjugates in the media from both glands with each oestrogen. Sub sequently, sulphoconjugated steroids and glucuronidates were recovered in s eries from C-18 cartridges after solvolysis and enzyme hydrolysis respectiv ely. Furthermore, about one-third of the conjugated fraction in each case r emained unhydrolysed after these treatments. In conclusion, it is clear tha t a study of the actions of oestrogens on these glands must consider the dy namics of metabolism of the oestrogens presented to them by the testes and would include conjugation of steroids by the glands themselves.