PubMed · 4548866
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P Franchimont, J C Valcke, R Lambotte. 1974. Female gonadal dysfunction.. https://doi.org/10.1016/s0300-595x(74)80039-3
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Previous work has demonstrated that dehydroepiandrosterone (DHEA) strongly inhibits growth and de novo cholesterol (CH) biosynthesis in preneoplastic rat liver. Administration of a mixture of 4 ribo- or deoxyribonucleosides of adenine, guanine, cytosine and uracil/thymine, prevents growth inhibition but not inhibition of CH synthesis. The purpose of this paper was to identify the site of inhibition of CH synthesis by DHEA. Persistent nodules (PNs) were induced, in diethylnitrosamine-initiated male F344 rats, by 'resistant hepatocyte' protocol. Fifteen weeks after initiation, nodule bearing rats and normal controls received a diet containing 0.6% DHEA for 3 weeks. They were then killed. 3-Hydroxy-3-methylglutaryl-CoA reductase (HMGR) activity and mRNA levels were 18- and 14-fold higher, respectively in nodules than in normal liver. DHEA strongly inhibited HMGR activity in both tissues in vivo, but had a slight effect on HMGR activity, when added in vitro to the reaction mixture for determination of this activity. In vivo DHEA treatment caused a 65% decrease in the level of HMGR mRNA in PNs, which, however, does not seem to completely account for the decrease in HMGR activity (83%). Low density lipoprotein receptor (LDL-R) mRNA level underwent a slight decrease in PNs, with respect to control liver, which did not lead to a significant decrease in 125I-LDL binding to LDL-R. DHEA treatment caused 30% and 24% increases in LDL-R expression and 125I-LDL binding, respectively, in nodules. These observations indicate that in addition to HMGR gene expression, increased influx of LDL into preneoplastic cells may contribute to the deregulation of mevalonate synthesis by DHEA. The observation that HMGR activity and gene expression were still 3- to 5-fold higher in PNs of DHEA-treated rats than in control liver, and previous findings of preneoplastic liver cell growth in the presence of relatively low CH synthesis, suggest that even relatively low levels of mevalonate are sufficient for the growth of preneoplastic liver cells.
A case of adrenocorticotropic hormone independent bilateral adrenocortical macronodular hyperplasia (AIMAH) is reported. A 59 year old male was admitted to hospital because of hypertension. Subsequently, hypercortisolism, low plasma adrenocorticotropic hormone (ACTH), loss of diurnal rhythm of ACTH, lack of suppression with high dose dexamethasone were found and bilateral adrenal enlargement was detected by abdominal computerized tomography and adrenal scintigraphy. Bilateral total adrenalectomy was performed under a diagnosis of bilateral adrenal hyperplasia associated with Cushing's syndrome. Both adrenal glands were enlarged in size and weight. Bulging nodules were found at the cut section. Microscopically, a variegated histologic pattern including trabecular, adenoid and zona glomerulosa-like (ZG-like) structures was revealed in the nodules. Immunohistochemical examination disclosed positive staining of cytochrome P-450 17 alpha, negative of 3 beta-HSD in the ZG-like structure. Ultrastructurally, the cells composing the ZG-like structure were similar to those of the ZG in normal adrenal cortex. The authors agree that AIMAH is one of the entities causing Cushing's syndrome, and advise pathologists to keep this disorder in mind when they examine the adrenals in Cushing's syndrome.
In a previous study we demonstrated that, in children affected with isolated GH deficiency, an acute high-dose human recombinant GH (hrGH) treatment increases the 11-deoxycortisol and induces an IGF-I responsiveness to ACTH. The aim of the present study was to reevaluate, in the same children, the adrenal and IGF-I responsiveness to ACTH after a chronic replacement-dose GH therapy. Ten children (seven males and three females, mean age 7 years) affected with isolated GH deficiency underwent a synthetic ACTH 1-17 test before and after sc administration of human recombinant GH at a dose of 0.6 UI/kg/week for 3 months. After therapy, the 11-deoxycortisol responsiveness to ACTH significantly decreased compared with that observed after acute treatment (P < 0.001), and so it returned to baseline. No differences were detected in the responsiveness to ACTH of cortisol, dehydroepiandrosterone-sulphate, D4-androstenedione, and 17-hydroxyprogesterone. On the other hand, the chronic treatment induced an IGF-I responsiveness to ACTH (P < 0.001). In conclusion, our study demonstrates that, in isolated GH deficiency, replacement doses of hrGH do not modify the adrenal steroid basal levels or its responsiveness to ACTH, whereas both replacement and high doses of hrGH induce an IGF-I responsiveness to ACTH.