|Kemper Green, C|
|Carroll, Jeffery - Jeff Carroll|
Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 5/13/1999
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 protein, cytochrome P450 cholesterol side chain cleavage enzyme (P450) and 3beta-hyd teroid dehydrogenase (3B-HSD) in gonads of perinatal pigs was determined to contrast age- and sex-related differences. 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 neonatal boars (n=6/age group). StAR, P450 and 3B-HSD protein content was determined by Western blot procedures. StAR was not detectable in fetal or neonatal ovaries; however, P450 and 3B-HSD were detected in these same ovaries. Ovarian P450 appeared at a similarly low level for each age group, whereas ovarian 3B-HSD content doubled from the fetal stage to 3 wk of postnatal age. StAR, P450 and 3B-H Hntent was greater in testes than in age-matched ovaries. StAR was present in fetal testicular samples, and was increased in testes from boars 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 was lower in testes obtained from newborn (1-h-old) and 3-wk-old boars relative to fetal and 2-wk-old boars. 3B-HSD protein was detected in all perinatal boar samples and was relatively unchanged over the times examined. In Study II, testis weight increased 9.7-fold between 1 and 14 d of age while the number of Leydig cells per testis increased 4.8-fold. Testis content of 3B-HSD level did not differ while StAR and P450 each increased about 4-fold between 1 and 14 d of age. Perinatal and peripubertal pigs are useful models to study the ontogeny of proteins associated with gonadal steroid producing capacity.