A study of some major testicular steroids in the pig in relation to their effect on the development of male characteristics in the prepubertally castrated boar

Abstract

Prepubertally castrated boars received subcutaneous injections twice weekly, from 12 to 38 weeks of age, of testosterone or 5-androstenediol (5-androstene-3 beta,17 beta-eiol) (2 mg/5 kg), or each of these steroids in combination with oestrone (1 mg/5 kg). All steroid treatments induced growth and secretory activity of the accessory organs. The prostate was maintained best by testosterone, and the seminal vesicles by 5-androstenediol. No specific effects of oestrone on these organs were found. Champing of excess saliva was induced in all treated pigs when they were introduced to an oestrous gilt, but only boars receiving testosterone displayed intense mating behaviour including mounting and, in 3 animals, ejaculation; no specific effects of oestrone on behaviour were seen. Low normal levels of unconjugated androgen, and normal to high levels of unconjugated oestrogen were circulating in the treated pigs. There was evidence that peripheral metabolism of exogenous steroids had occurred: 5-androstenediol to testosterone, these two androgens to oestrogen, and sulphation of oestrogen. The sulphate conjugates of dehydroepiandrosterone, 5-androstenediol and oestrone predominated in the peripheral plasma of mature intact boars. Concentrations of 3 alpha-androstenol (5 alpha-androst-16-en-3 alpha-ol) in the submaxillary glands of androgen-treated pigs were similar to those in untreated castrates, thus indicating that androgens are probably not precursors of the pheromonal 16-androstene steroids in vivo.

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

“…However, somewhat paradoxically, we have observed some hydrolysis of oestrone sulphate by both glands (J I Raeside, H L Christie, R L Renaud, unpublished data), as noted previously by Booth (1983). Because testicular secretion of oestrone and its circulation in peripheral blood are principally in the form of oestrone sulphate (Booth 1980, Claus & Hoffman 1980, Setchell et al 1983) such hydrolysis in vitro may imply physiological significance.…”

Development of some male characteristics supported by oestrone but not dehydroepiandrosterone in the boar

“…There is evidence indicating that DHA and 5-androstenediol may be important precursors of testosterone in the pig testis (Ruokonen, 1978) as has been suggested for the testes of dogs (Yamaji, Motohashi, Tanioka & Ibayashi, 1968;Oh & Tamaoki, 1973) and men (Vihko & Ruokonen, 1975). However, there is also evidence indicating that, in the boar, 5-ene unsaturated C19 steroids may be important prohormones for testosterone in extragonadal tissues such as the submaxillary gland (Booth, 1977) and the accessory sex organs (Booth, 1980). Administration of 5-androstenediol to prepubertally castrated boars (2 mg/5 kg) maintained the accessory organs in a manner comparable to that produced by the same amount of testosterone (Booth, 1980).…”

Effects of age and live weight on the sexual development of gilts and boars fed two planes of nutrition

“…Cervix weight and length increased (P < 0.01) to a lesser extent ( x 1.4 and x 1.2, respectively) after puberty. (Joshi and Raeside, 1973 ;Morat et al 1980 ;Booth, 1980Booth, , 1983Lauwers et al, 1981) and undernutrition is known to reduce androgen production (Dickerson et al, 1964 ;Bonneau, 1987 (1983). However, the growth performances in the study of Den Hartog and Noordewier (1984) were similar to ours, while in that of Etienne et al (1983) gilts fed ad libitum had a slower growth rate so that they were one month older at 125 kg of live weight.…”