Steroid fatty acid esters in adrenals and plasma: effects of ACTH

Abstract

The presence and production of 5-ene-steroid fatty acid esters (SFA) has been previously reported in bovine adrenals. A study was conducted, using a series of chromatographic procedures and radioimmunoassays, to determine the levels of SFA in adrenals from man, cattle, dog, rat and guinea-pig, and to assess, in both rats and guinea-pigs, the effect of ACTH on SFA production by adrenals and their subsequent secretion into the circulation. The effects of ACTH on plasma SFA and non-conjugated steroid levels were also investigated in human subjects. Our data indicated that adrenal pregnenolone fatty acid ester (PREG-FA) levels were below 40% of PREG levels in cattle, dog, rat and guinea-pig while, in man, PREG-FA levels were threefold those of PREG. A large proportion of dehydroepiandrosterone (DHEA) and 5-androstene-3 beta, 17 beta-diol were present as fatty acid ester derivatives in the adrenals of all species, with the exception of cattle. In both rats and guinea-pigs, administration of ACTH caused a sharp increase in adrenal PREG of approximately threefold which lasted for 6 h, while the concentration of adrenal PREG-FA was slightly increased for a short time. In plasma, however, a marked rise in PREG-FA occurred, while the changes in PREG levels were much lower than those of its acylated counterpart. In man, PREG and DHEA concentrations were rapidly stimulated two-fold in the first 30 min following the administration of ACTH, while PREG-FA and DHEA-FA levels were increased by approximately 2.5-fold (P less than 0.01) at 120 and 180 min.(ABSTRACT TRUNCATED AT 250 WORDS)

Fatty acid esters of steroids: Synthesis and metabolism in lipoproteins and adipose tissue

“…Recently, Jung et al [83] analyzed intact saturated fatty acid esters of dehydroepiandrosterone and pregnenolone in five women and men by GC-MS. In contrast to previous work, the reported male plasma concentration of a representative pregnenolone fatty acid ester, pregnenolone 3-stearate, was over 100 times higher (99-1800 nmol/l) than the total plasma pregnenolone fatty acid ester concentration as previously analyzed by indirect methods (1-6.5 nmol/l) [2,54,84]. Unfortunately, the plasma concentration of unesterified pregnenolone was not reported [83].…”

Novel lipoidal derivatives of pregnenolone and dehydroepiandrosterone and absence of their sulfated counterparts in rodent brain

“…These known lipoidal steroid conjugates have been found in several tissues (54,56), and several authors have suggested that C 21 , C 19 , and C 18 steroids linked to fatty acids via hydroxyl functions at positions C-3, C-17, and C-21 are sequestered in tissues in which the unconjugated steroid can be released by the action of intracellular esterases (57). Furthermore, these esters of PREG, DHEA, androst-5-ene-3␤,17␤-diol, and estradiol can be formed in plasma of several mammalian species (58,59). It has also been shown that plasma lipoproteins serve as carriers of PREG and DHEA fatty acid esters because of their very low aqueous solubility (60).…”

During Anesthetic-Induced Activation of Hypothalamic Pituitary Adrenal Axis, Blood-Borne Steroids Fail to Contribute to the Anesthetic Effect

“…Pituitary hormones, by acting on specific target cells, can increase the circulating pregnenolone and progester one content [22] and these stereoids are taken up by the brain [23]. In order to establish whether chloral hydrate, ethanol, and urethane increase the content of brain ste roids by acting directly on brain steroid biosynthesis or indirectly via an increase secretin of pituitary hormone acting on steroidogenic cells we injected chloral hydrate to hypophysectomized or castrated-adrenalectomized rats.…”