Biomedical subjects

E Stoner

Publications and source records attributed to E Stoner.

60 records · Page 4Linked to original sources

PubMedDate not supplied

Effect of MK-906, a specific 5 alpha-reductase inhibitor, on serum androgens and androgen conjugates in normal men.

To determine the hormonal effects of MK-906, an orally active 5 alpha-reductase inhibitor, on serum androgens and androgen conjugates, 12 healthy men were given 10, 20, 50, and 100 mg MK-906 2 weeks apart in randomized order in a 4-period crossover design. Serum testosterone (T), dihydrotestosterone (DHT), androstanediol glucuronide, and androsterone glucuronide were measured before and 24 hours after each dose. The effect of MK-906 on glucuronyl transferase activity, the enzyme responsible for androstanediol glucuronide and androsterone glucuronide formation, was assessed in vitro using rat prostate tissue. Serum T levels were unchanged after all doses. Serum DHT, androstanediol glucuronide, and androsterone glucuronide were suppressed by 70, 40, and 56%, respectively, after the 10-mg dose, and by 82, 52, and 66% after the 100-mg dose (P less than 0.02 for the comparison between the 10 and 100-mg doses for all three steroids), respectively. Baseline serum T and DHT levels were strongly correlated (R = 0.89, P = 0.0002), as were androstanediol glucuronide and androsterone glucuronide levels (R = 0.78, P = 0.003), but there was no correlation between DHT levels and the levels of either conjugated steroid. MK-906 had no effect on glucuronyl transferase activity in vitro. It was concluded that single doses of MK-906 suppress both conjugated and unconjugated 5 alpha-reduced androgens. While all three steroids appeared to be good markers of systemic 5 alpha-reductase inhibition, further research will be needed to determine which steroid best reflects tissue DHT levels in patients receiving these inhibitors.

5-alpha Reductase Inhibitors↗

PubMedDate not supplied

Empty sella syndrome in childhood.

The empty sella syndrome is common in middle-aged women, usually presenting with headache, and only occasionally associated with endocrine or visual abnormalities. It is rare in childhood. Childhood cases tend to present either with endocrine disturbances, visual symptoms, or with craniofacial syndromes. We present three cases of complete empty sella with childhood onset, each discovered unexpectedly during evaluation of endocrine or visual dysfunction.

Adolescent↗

PubMedDate not supplied

Primary hyperaldosteronism in childhood due to unilateral macronodular hyperplasia. Case report.

We present the first report of primary hyperaldosteronism in childhood due to unilateral macronodular hyperplasia. A 10-year-old white boy with severe hypertension (150/100 mm Hg), hypokalemia (1.4 mEq/liter), and suppressed plasma renin activity (PRA) (less than 0.1 ng/ml/hr) demonstrated fixed PRA and aldosterone (aldo) levels that did not change with alteration of dietary sodium. The paradoxical decrease in serum aldo on assumption of upright posture suggested a tumor. Prolonged ACTH administration produced a continuous rise in blood pressure, but a transient rise in aldo. A minimal decrease in urinary aldo during dexamethasone administration was noted, excluding dexamethasone-suppressible hyperaldosteronism. Blood pressure normalized with spironolactone. Computerized transaxial tomography, iodocholesterol scanning, and adrenal venography were not diagnostic of a discrete adrenal lesion. Although hyperplasia is more common than an adenoma as a cause of hyperaldosteronism in childhood, a tumor was predicted, since adrenal vein hormone sampling with ACTH stimulation lateralized aldosterone secretion unequivocally to the left adrenal gland. However, left adrenalectomy revealed macronodular hyperplasia. Postoperatively, there was reversal of hypertension, hypokalemia, and hyperaldosteronism. Thus, in childhood, unilateral hypersecretion of aldosterone may result from nodular hyperplasia, rather than a discrete adenoma.

Adrenal Glands↗

PubMedDate not supplied

Evaluation of percutaneous transluminal renal angioplasty in childhood hypertension.

Percutaneous transluminal renal angioplasty (PTRA) has been infrequently used in the treatment of children with hypertension due to renal artery stenosis. We report our results in five patients aged 4 to 22 years with hypertension diagnosed at ages 1 1/2 to 10 years. Four of the five patients had been on antihypertensive medication prior to angioplasty. Four had fibromuscular disease and one had probable Takajasu's arteritis; two had solitary kidneys. Following angioplasty, a prompt decrease in blood pressure was observed in all patients. Further, four of five patients after PTRA were normotensive without antihypertensive medications, and in all PRA declined. PTRA can be a safe and effective alternative to surgical treatment in the management of renovascular hypertension in childhood. We suggest that PTRA should be the first procedure attempted to correct renovascular hypertension in children.

Adolescent↗

PubMedDate not supplied

Effect of finasteride on adrenal steroidogenesis in men.

Finasteride, a 5 alpha-reductase inhibitor, does not bind to the androgen receptor and has no other known hormonal activity. To determine what effect, if any, it has on adrenal steroidogenesis, 10 healthy men received 5 mg finasteride daily for 28 days. Adrenocorticotropic hormone (ACTH) stimulation tests were performed before and after 4 weeks of finasteride administration (5 mg daily). Serum levels of 17-hydroxypregnenolone, 17-hydroxyprogesterone, deoxycorticosterone, corticosterone, aldosterone, cortisol, dehydroepiandrosterone, and androstenedione were measured before and 60 minutes after i.v. ACTH. Finasteride decreased serum dihydrotestosterone levels from 31 +/- 5 to 4.4 +/- 1.2 ng/dl (P < 0.001). There were no significant changes in basal or ACTH-stimulated serum levels of adrenal steroids. There was also no significant decrease in the product to precursor ratio for the seven adrenal enzymes tested. Finasteride increased mean serum androstenedione levels by 17% (P = 0.10) and significantly increased the androstenedione to 17-hydroxyprogesterone ratio (P = 0.02 before ACTH and 0.05 after ACTH). These changes are most likely due to inhibition of androstenedione metabolism by 5 alpha-reductase. In conclusion, finasteride has no detectable effect on adrenal steroidogenesis, other than that which can be explained by inhibition of the 5 alpha-reductase enzyme.

5-alpha Reductase Inhibitors↗

PubMedDate not supplied

[The long-term treatment of patients with benign prostatic hyperplasia using Proscar].

The drug proskar (finasterid) has been developed and synthetized in "Merck Sharp & Dohme" research laboratories and tried initially in healthy male volunteers. Proskar is highly active as a blocker of 5-alpha-reductase blocking conversion of testosteron in dehydrotestosteron (DHT). The assessment of proskar effect on the prostate has been performed in 2000 patients throughout the world, including Russia. Follow-up studies (up to 5 years) demonstrate that proskar in the dose 5 mg/day produces a reduction in the levels of specific prostatic antigen, serum DHT and prostatic size, an increase in urination rate, life quality. In benign prostatic hyperplasia proskar realizes its effect in hormonal nature of the disease. The advantages are also safety and rare occurrence of side effects. The response became noticeable on the treatment month 6.

5-alpha Reductase Inhibitors↗