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The adrenal cortex
Published in Martin Andrew Crook, Clinical Biochemistry & Metabolic Medicine, 2013
Adrenocorticotrophic hormone is a single-chain polypeptide made up of 39 amino acids with biological activity at the N-terminal end of the peptide. A peptide consisting of this sequence has been synthesized (tetracosactide, Synacthen) and can be used for diagnosis in place of ACTH. The ACTH stimulates cortisol synthesis and secretion by the adrenal cortex. It has much less effect on adrenal androgen production and, at physiological concentrations, virtually no effect on aldosterone production.
Neurological Manifestations of Medical Disorders
Published in John W. Scadding, Nicholas A. Losseff, Clinical Neurology, 2011
David and John Scadding Werring, John Scadding
There is sodium and water depletion from mineralocorticoid deficiency, causing a low sodium, raised urea and potassium and, in a few patients, a raised calcium level. The plasma cortisol is low and the ACTH raised. An ACTH stimulation test with an injection of 250 mg i.m. of soluble ACTH (tetracosactide) normally shows a rise in cortisol level unless there is adrenal failure.
DropWise: current role and future perspectives of dried blood spots (DBS), blood microsampling, and their analysis in sports drug testing
Published in Critical Reviews in Clinical Laboratory Sciences, 2023
M. Thevis, Katja Walpurgis, A. Thomas
A major benefit of DBS in direct comparison to urine and venous blood samples is the considerable analyte stability, which can be attributed to the reduced enzymatic activity and elimination of humidity by dehydratization [33–35]. For instance, tetracosactide (Synacthen®) is a peptidic drug highly susceptible to degradation in both urine and plasma specimens, and its degradation can only be prevented by immediate freezing following sample collection [36,37]. Conversely, Tretzel et al. could demonstrate that tetracosactide is stable for at least 10 days in DBS stored at RT, which would be an enormous advantage for routine doping controls [33]. The same applies to short-chained steroid esters such as testosterone acetate and propionate, which have shown to be rapidly degraded in venous blood samples stored at RT due to enzymatic hydrolysis by esterases [38]. Both immediate freezing of the samples [39] and the use of blood collection tubes stabilized with the esterase inhibitor sodium fluoride (NaF) [38] can prevent degradation; however, the use of DBS could be a very promising alternative as different testosterone esters were found to be only slightly to moderately unstable in DBS stored for 4 or 8 weeks at RT [34,35].
Occurrence of Hypopituitarism in Tunisian Turner Syndrome patients: familial versus sporadic cases
Published in Gynecological Endocrinology, 2021
M. Mnif-Feki, W. Safi, N. Bougacha-Elleuch, G. Abid, M. Moalla, M. Elleuch, D. H. Ben Salah, N. Rekik, N. Belguith, F. Abdelhedi, T. Kammoun, M. Hachicha, N. Charfi, F. Mnif, H. Kammoun, H. Hadj Kacem, F. Hadj-Kacem, M. Abid
Hormone dosing was carried out by means of standard Radio Immuno-Assays. ACTH deficiency (ACTH-D) was suspected when the 08 a.m. cortisol level was between 50–180 ng/ml and confirmed by an impaired cortisol response to the stimulation Synactyn test (1 µg tetracosactide) below 180 ng/ml with normal or low basal plasma levels of ACTH [5]. Gonadotropin insufficiency was confirmed when low serum estradiol levels (<40 pmol/l) were associated with inappropriately low serum gonadotropin concentrations. Thyreotrope deficiency was confirmed when inappropriately low serum TSH levels were associated with subnormal serum-free T4 concentrations. Growth hormone deficiency (GH-D) was established by the failure of GH to raise more than 10 ng/ml after a provocative test (insulin tolerance test). All patients were tested for GH after administration of insulin (0.1 U/kg veinously). Blood sample measurements of serum GH were obtained at 0, 30, 60, 90, and 120 min.
Hypophysitis related to immune checkpoint inhibitors: An intriguing adverse event with many faces
Published in Expert Opinion on Biological Therapy, 2021
Maria V Deligiorgi, Charis Liapi, Dimitrios T Trafalis
During the diagnostic work-up of ir hypophysitis, the basal cortisol and ACTH levels should be interpreted cautiously. The Endocrine Society advocates considering any 08:00 AM cortisol concentration below 140 nmol/l (5 μg/dl) as a preliminary test suggestive of adrenal insufficiency. A short corticotropin stimulation test (short Synacthen test [SST]) is recommended to confirm or exclude the diagnosis. Adrenal insufficiency is confirmed by cortisol levels below 500 nmol/l (18 μg/dl) (assay dependent) measured at 30 and 60 min after administration of 250 μg tetracosactide (synthetic peptide consisting of the first 24 of the 39 amino acids of the endogenous ACTH peptide) intravenously (iv) (or intramuscularly) [101]. However, the American Society of Clinical Oncology (ASCO) Clinical Practice Guidelines consider any cortisol concentration exceeding 500 nmol/l (18 μg/dl) at any time of day adequate for exclusion of adrenal insufficiency and any cortisol concentration less than 138 nmol/l (5 μg/dl) adequate for diagnosis of adrenal insufficiency. According to ASCO guidelines, the Synacthen 250 μg test should be performed only in case of 08:00 AM cortisol concentration between 138 and 500 nmol/l (5–18 μg/dl) [95]. Confirmed cortisol deficiency accompanied with low ACTH levels sets the diagnosis of secondary adrenal insufficiency [101].