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K Von Werder

Publications and source records attributed to K Von Werder.

8 recordsLinked to original sources

Criteria for cure of acromegaly: a consensus statement.

In February 1999, a workshop was held in Cortina, Italy to develop a consensus defining the criteria for cure of acromegaly. The workshop was sponsored by the University of Brescia and hosted by the Italian Society of Endocrinology. Invited international participants included endocrinologists, neurosurgeons, and radiotherapists skilled in the management of acromegaly. This statement summarizes the consensus achieved in these discussions.

Acromegaly↗

Acute dexamethasone suppression of ACTH secretion stimulated by human corticotrophin releasing hormone, AVP and hypoglycaemia.

In order to obtain more insight into the mechanisms regulating endogenous ACTH secretion in humans we studied the inhibitory effect of acute i.v. dexamethasone administration on ACTH release under various conditions. Six male volunteers were subjected to six different protocols. After combined i.v. injection of 100 micrograms corticotrophin releasing hormone (CRH) and 100 micrograms growth hormone releasing hormone (GRH) there was the expected rise in ACTH (area under the curve, 1053 +/- 204 (SE) (pmol/l) min) and cortisol (59788 +/- 10098 (nmol/l) min) rise which was suppressed by prior i.v. injection of 2 mg dexamethasone (ACTH: 444 +/- 63 (pmol/l) min; cortisol: 28528 +/- 2152 (nmol/l) min). Insulin hypoglycaemia (IH) led to a more pronounced ACTH and cortisol rise compared with CRH (6307 +/- 817 (pmol/l) min and 82080 +/- 21934 (nmol/l) min, respectively) which was not completely suppressed by prior pretreatment with dexamethasone (ACTH, 580 +/- 103 (pmol/l) min; cortisol: 55649 +/- 5821 (nmol/l) min). Combined AVP/CRH injection (10 IU/100 micrograms) after pretreatment with dexamethasone (344 +/- 41 (pmol/l) min for ACTH; 32832 +/- 3173 (nmol/l) min for cortisol) could not reproduce the ACTH secretion following IH after pretreatment with dexamethasone (579 +/- 103 (pmol/l) min for ACTH and 55649 +/- 5821 (nmol/l) min for cortisol). In all subjects a saline control with 2 mg dexamethasone was performed. These findings confirm the acute inhibitory effect of glucocorticoids on CRH-stimulated ACTH secretion. Since CRH-induced ACTH secretion is almost completely abolished by administration of dexamethasone the ACTH rise following IH after dexamethasone can not be mediated by endogenous CRH alone. Moreover, since the addition of AVP to CRH (after dexamethasone suppression) could not reproduce the ACTH rise during IH after dexamethasone pretreatment, an additional, yet unknown factor stimulating ACTH secretion may be involved. In the same protocols, no significant difference could be observed comparing IH and GRH induced GH secretion (4948 +/- 1172 (mU/l) min vs 3596 +/- 820 (mU/l) min, NS); furthermore, in contrast to results obtained by chronic steroid administration, acute i.v. dexamethasone pretreatment did not affect IH or GRH-induced GH secretion (4110 +/- 666 (mU/l) min vs 2916 +/- 462 (mU/l) min, NS). The GRH-stimulated GH secretion (3596 +/- 820 (mU/l) min) was not suppressed by prior intravenous treatment with dexamethasone (2916 +/- 504 (mU/l) min, NS).

Adrenocorticotropic Hormone↗

Altered hypothalamic-pituitary-adrenal responsiveness to dexamethasone-insulin tolerance test in active acromegaly.

Eight acromegalic patients showed a plasma cortisol (11-OHCS) rise after insulin hypoglycemia which was similar to that seen in control patients, with mean peak values (+/-SEM) of 23.2 +/- 3.5 mug/100 ml and 27.2 +/- 3.3 mug/100 ml, respectively. One mg of dexamethasone was given the evening prior to repeat insulin hypoglycemia (DEX-ITT). After dexamethasone, the control subjects showed a mean post hypoglycemic plasma 11-OHCS rise to 18.3 +/- 2.3 mug/100 ml. In contrast, acromegalic patients had a negligible rise is plasma 11-OHCS, despite a comparable degree of hypoglycemia. These data indicate that, in active acromegaly, abnormal hypothalamic-pituitary-adrenal suppressibility can be induced to insulin hypoglycemia after dexamethasone.

11-Hydroxycorticosteroids↗