PubMed · 8753287
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A Kambegawa. 1995. [Androsterone].. https://pubmed.ncbi.nlm.nih.gov/8753287/
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The St-20 and ST-40 cDNAs encode rat liver hydroxysteroid sulfotransferases (HS-ST) that are 90% identical in amino acid sequence but exhibit different substrate preferences for dehydroepiandrosterone (DHEA), androsterone (AD), and cortisol (CS). ST-40 is active for all three substrates, whereas ST-20 is mainly active for cortisol. To determine the domain responsible for the substrate preferences of the HS-STs, 20 chimeric HS-STs were constructed by reciprocal exchanges of DNA fragments derived from the cDNAs and were expressed in Escherichia coli. Some chimeric enzymes were enzymatically active for all three substrates, and some displayed reduced or lost CS-ST activity, with retention of DHEA- and AD-ST activities. Others lost all HS-ST activity. Analysis revealed that a central region (region III spanning amino acids 102-164 with five amino acid differences between ST-20 and ST-40) is essential for HS-ST activity, whereas regions II (amino acids 65-101) and IV (amino acids 165-219) are unimportant with regard to substrate preference. It was also shown that the parental combination of regions I (amino acids 1-64) and V (amino acids 220-284) is essential for CS-ST activity. Photoaffinity labeling with [35S]3'-phosphoadenosine 5'-phosphosulfate (PAPS) revealed that some inactive chimeras lost affinity for PAPS. These results suggested that an ordered structure formed by regions I, III, and V is required for HS-ST activity, especially for substrate preference and PAPS binding.
The aim of this study was to assess the possible role of growth hormone (GH) on androsterone synthesis. This effect was analyzed in theca-interstitial cells obtained from immature female rats. The addition of GH to the cultures significantly stimulated androsterone (A) synthesis in a dose- and time-dependent way and this effect was not due to a cellular number increase. When added to the hCG cultures, GH significantly enhanced androgen production even though it did not synergyze with the chorionic gonadotropin. The addition of antibodies anti-IGF-I to the GH cultures did not modify the growth hormone effect suggesting that GH probably does not require IGF-I to achieve its effect on A production. Finally, no effect of GH on cAMP levels were observed in the cultures at the end of the treatment. Our results demonstrate that GH is able to significantly induce A synthesis by rat theca-interstitial cells. Since the presence of GH and its receptors in the ovary is now well established the present data strongly suggest a potential relevance of GH in reproductive biology.
The gas phase electronic structure of dehydroepiandrosterone (3 beta-hydroxy-5 alpha-androstene-17-one, DHEA) is elucidated from its Het photoelectron spectrum, quantum chemical calculations, and correlation with spectra of the related molecules 5 alpha-androstene-17-one (I) and epiandrosterone (3 beta-hydroxy-5 alpha-androstane-17-one) (2). The lowest ionization energy event in DHEA is shown to correspond to a pi-ionization energy of approximately 8.5 eV, followed closely and overlapped in part by the carbonyl lone pair ionization at 8.7 eV.