|Carroll, Jeffery - Jeff Carroll|
Submitted to: Endocrine Society Meeting
Publication Type: Abstract Only
Publication Acceptance Date: 6/12/1999
Publication Date: N/A
Technical Abstract: Steroidogenic acute regulatory (StAR) protein is proposed to be the acute rate limiting step in steroidogenesis. The presence of StAR, cytochrome P-450 cholesterol side-chain cleavage enzyme (P450 SCC) and 3beta-hydroxysteroid dehydrogenase (3beta-HSD) in gonads of female and male perinatal pigs was determined to contrast age- and sex-related differences in these proteins. In Study I, ovaries (n=16) and testes (n=20) were obtained from fetal (113 d of gestation) and neonatal (<1-h-old, 2- and 3-wk-old) pigs. In Study II, testes were collected from 1- and 14-d-old boars (n=6/age group). StAR was not detectable by Western blot in fetal or neonatal ovaries; however, P450 SCC and 3beta-HSD were detectable. Ovarian P450 SCC appeared at a similarly low level for each age group, whereas ovarian 3beta-HSD content doubled from the fetal stage to 3 wk of age. The relative content of StAR, P450 SCC and 3beta-HSD was greater in the testes than in age-matched ovaries. StAR was present in testes at 113 d of gestation, and was increased at 2 wk (3-fold) and 3 wk of age (10-fold). StAR was not detected in testes from the 1-h-old boars. P450 SCC was lower in testes obtained from newborn and 3-wk-old boars relative to testes obtained from fetal and 2-wk-old boars. 3beta-HSD in all perinatal boars was relatively unchanged over the time. In Study II, testis weight increased 9.7-fold between 1 and 14 d of age and the number of Leydig cells per testis increased 4.8-fold. Boar testis content of 3beta-HSD did not differ while the relative content of StAR and P450 SCC each increased about 4-fold between 1 and 14 d of age. Young pigs are useful models to study the influence of age, sex, genotype and environmental factors on the ontogeny of proteins associated with gonadal steroid production.