{"type": "root", "children": [{"type": "p", "children": [{"type": "t", "text": "\n 17β‐Hydroxysteroid dehydrogenase type 11 (HSD17B11) is a member of the short‐chain dehydrogenase/reductase (SDR) family that plays a pivotal role in local steroid hormone metabolism. In several studies its primary catalytic activity has been demonstrated to be the oxidation of 5α‐androstane‐3α,17β‐diol into androsterone, indicating its key role in androgen inactivation and intracrine modulation of steroid action."}, {"type": "fg", "children": [{"type": "fg_f", "ref": "1"}]}, {"type": "t", "text": " In prostate and testicular tissues, altered expression of HSD17B11 (also referred to as Pan1b in some studies) has been associated with advanced disease features such as seminal vesicle invasion and spermatogenic arrest, suggesting that its androgen‐modulating activity may contribute to the progression of androgen‐dependent conditions."}, {"type": "fg", "children": [{"type": "fg_f", "ref": "3"}]}, {"type": "t", "text": "\n "}]}, {"type": "t", "text": "\n "}, {"type": "p", "children": [{"type": "t", "text": "\n At the cellular level, HSD17B11 is predominantly localized to the endoplasmic reticulum under basal conditions but redistributes to lipid droplets when their formation is induced. This dynamic subcellular targeting, which depends on an N‐terminal hydrophobic sequence and an adjacent motif related to the PAT domain, suggests that HSD17B11 may function not only in steroid conversion but also in the regulation of lipid droplet dynamics and lipid metabolism."}, {"type": "fg", "children": [{"type": "fg_fs", "start_ref": "5", "end_ref": "7"}]}, {"type": "t", "text": " In Leydig cells, for instance, its presence on lipid droplets appears to support testosterone synthesis by localizing key steroidogenic enzymes to sites of hormonal conversion."}, {"type": "fg", "children": [{"type": "fg_f", "ref": "8"}]}, {"type": "t", "text": "\n "}]}, {"type": "t", "text": "\n "}, {"type": "p", "children": [{"type": "t", "text": "\n Moreover, transcriptional regulation of HSD17B11 by factors such as Sp1 and C/EBPα in contexts like prostate cancer cells highlights further its importance in fine‐tuning androgen availability at the cellular level."}, {"type": "fg", "children": [{"type": "fg_f", "ref": "1"}]}, {"type": "t", "text": " Conservation of its function has also been observed in non‐mammalian species, including marine gastropods, where abalone HSD17B11 similarly catalyzes steroid conversions during different reproductive stages."}, {"type": "fg", "children": [{"type": "fg_f", "ref": "9"}]}, {"type": "t", "text": "\n "}]}, {"type": "t", "text": "\n "}, {"type": "p", "children": [{"type": "t", "text": "\n Finally, changes in HSD17B11 expression have been linked in other settings to shifts in metabolic responses, such as its downregulation in the heart under nitroglycerin tolerance conditions, and its capacity to influence lipid droplet-associated proteins like ATGL, suggesting a broader role in cellular lipid handling."}, {"type": "fg", "children": [{"type": "fg_f", "ref": "10"}]}, {"type": "t", "text": " Collectively, these observations indicate that HSD17B11 serves as an important modulator of both steroid hormone inactivation and lipid droplet dynamics, linking androgen metabolism to broader aspects of lipid homeostasis and potentially to the pathogenesis of hormone-dependent diseases.\n "}]}, {"type": "t", "text": "\n "}, {"type": "p", "children": [{"type": "t", "text": "\n (1,2,3,4,5,6,7,9,10,11,12)\n "}]}, {"type": "rg", "children": [{"type": "r", "ref": 1, "children": [{"type": "t", "text": "Mirja Rotinen, Joaquín Villar, Jon Celay, et al. 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