In patients with ACTH-secreting pituitary tumor the peri-tumoral normal corticotrophs were supposed to be suppressed by cronic hypercortisolemia since frequently they develop transient secondary adrenal insufficiency after pituitary tumor resection and during early postoperative days. We evaluated the ACTH dynamics during transsphenoidal surgery in 16 patients with ACTH-secreting pituitary tumors (6 cured by surgery, 8 not cured Cushing's disease patients and 1 cured by surgery and 1 not cured Nelson's syndrome patients) and tested the hypothesis that in these patients, ACTH secretion from the peri-tumoral normal corticotrophs is inhibited and hence removal of the entire tumor should result in subtle postoperative reduction in plasma ACTH. Blood samples for ACTH determination were obtained from 14 Cushing's disease patients immediately before pituitary gland manipulation and 10, 30, 60, 90, 120, 150 and 300 min after pituitary tumor resection and on postoperative day one. In Nelson's syndrome patients the blood sample was obtained only after tumor removal. All patients received intravenous hydrocortisone during surgery and on the first postoperative day. Patients were considered cured by surgery if they presented adrenal insufficiency after hydrocortisone withdrawal. Mechanical pituitary manipulation induced increase in ACTH level. In all 14 Cushing's disease patients (cured and not cured), mean plasma ACTH levels were significantly greater 10 min after pituitary tumor resection (54.4+/-12.8 pmol/l) than in the premanipulation period (ACTH=26.3+/-5.3 pmol/l) (p=0.005). In Cushing's disease patients, the ACTH levels did not change significantly until 300 min after pituitary tumor resection either in those 6 patients cured by surgery (at 10 min after pituitary tumor resection ACTH was 54.4+/-12.8 pmol/l for all 14 Cushing's disease patients and at 300 min after tumor removal ACTH was 39.0+/-12.6 pmol/l for cured and 41.3+/-15.7 pmol/l for not cured Cushing's disease patients). The ACTH level also persisted high until 300 min after complete pituitary tumor resection in one cured patient with Nelson's syndrome. ACTH level does not change in the early recovery period after ACTH-secreting pituitary tumor, even in those cured patients, and probably peri-tumoral normal corticotrophs are not completely suppressed by cronic hypercortisolemia (and acute glucocorticoid administration) when these patients are under intense stress, like transsphenoidal surgery. Mechanical pituitary manipulation may induce ACTH release in patients with ACTH-secreting pituitary tumors but probably does not interfere in the maintenance of high ACTH-levels during the early postoperative period, since ACTH half-life is only 8-15 min. In patients with ACTH-secreting pituitary tumors, the behavior of the human hypothalamic-pituitary-adrenal system during transsphenoidal surgery does not conform to the specifications of a negative feedback mechanism.

Two boys are described with precocious puberty (PP) due to pineal immature teratoma associated with choriocarcinoma. Patient 1 was a 7 year-old boy with a 2-year history of PP. He had elevated CSF and plasma beta-hCG levels. Magnetic resonance imaging (MRI) showed a 3.0 cm pineal mass. He was initially submitted to a trial with radiotherapy, followed by radical surgical resection, stereotactic radiotherapy and chemotherapy. Long-term follow up included the appearance of acute hydrocephalus requiring CSF shunting, local hemorrhage and extensive radionecrosis. Death occurred 1.5 years after diagnosis. Patient 2 was a 7 year-old boy with an 8-month history of PP. He had elevated CSF and plasma beta-hCG and alpha-fetoprotein levels. MRI showed a 1.0 cm pineal mass. He was submitted to radical surgical resection (which caused normalization of levels of markers) and prophylactic chemotherapy. The boy is doing well 1.5 years after diagnosis. An extensive review of the literature corroborates the idea that this last treatment paradigm (surgery and chemotherapy) probably represents the best treatment regimen for these patients.

It has recently been suggested that the classical routine of glucocorticoid administration before and after transsphenoidal surgery (TSS) in Cushing's disease (CD) patients may not be necessary, since it is likely that peritumoral normal corticotrophs are not completely suppressed during this period. We compared the dynamics of ACTH and cortisol from a group of CD patients (cured and not cured), receiving no steroids post-operatively, with a control group of acromegalic patients who presented normal hypothalamic-pituitary-adrenal (HPA) axis. Blood samples for ACTH and cortisol determination were obtained immediately before, at the end of surgery and at 4, 8, 12, 16, 24, 48 and 72 h after surgery, in 8 cured CD patients (Group I), 9 not cured CD patients (Group II) and in 7 subjects with acromegaly (Group III) who presented normal HPA axis (control group). The mean ACTH level in Group I was significantly lower than in Group III from 4 to 12 h and lower than in Group II from 8 to 12 h post-operatively. The mean cortisol level in Group I was lower than in Groups II and III from 8 to 72 h after surgery. No difference in mean cortisol level was observed among Groups II and III during the evaluated period. The lowest cortisol value in Group II was 193 nmol/l (at 24 h after surgery) and in Group I patients, after 20 h post-operatively, the highest cortisol level was 165 nmol/l. Although all cured CD patients (Group I) presented serum cortisol level lower than 55 nmol/l until 72 h after surgery, none had significant complications related to adrenal insufficiency. Ours findings are in agreement with recent observations that there is probably no need for glucocorticoid administration until clinical and/or laboratorial data are suggestive of adrenal insufficiency. However, we have also shown that a subphysiological HPA axis response could be observed in cured CD patients after TSS, and a definitive conclusion about glucocorticoid management during and after this procedure could not be made on the ground of the few cases studied in the literature.

Familial hypopituitarism represents a clinically and genetically heterogeneous disorder. In a subset of these families, defects in Pit-I, a transcription factor essential for proper pituitary development have been identified as underlying molecular cause. These patients present extreme short stature, GH, PRL and TSH deficiency but intact ACTH, LH and FSH secretion. The pituitary is usually hypoplastic. In this report we describe a consanguineous family (the parents are first cousins) with thirteen siblings. Of the ten living siblings, four (two males and two females) have panhypopituitarism with severe growth failure. They had evidence of growth hormone, prolactin and gonadotropin deficiencies and developed central hypothyroidism late in life. ACTH secretion was normal. Bone age was retarded and dual-photon bone densitometry indicated severe osteoporosis. Combined provocative tests for pituitary hormones indicated blunted responses for GH, LH, FSH and a modest rise in serum PRL and TSH. A clonidine-test failed to induce pituitary GH response. A corticotropin-releasing factor (CRF) provocative test was conducted after 6 months without the use of prednisone with a normal ACTH response after CRF in the affected sibling. Plasma IGF-I and IGF-BP3 were below normal levels. Serum E2 (females) and serum testosterone (males) levels were very low. MRI evaluation of the pituitary indicated pituitary aplasia in all subjects. The phenotype described in this kindred is different from families reported with Pit-1 mutations. However, it resembles previously published kindreds with similar clinical and biochemical findings. The relative preservation of ACTH suggests a genetic defect early in pituitary gland development.

Altered GH responses to several pharmacological stimuli, including GHRH, have been found in hyperthyroidism. The mechanisms underlying these disturbances have not been fully elucidated. GH-releasing peptide-6 (GHRP-6) is a synthetic hexapeptide that specifically stimulates GH release both in vitro and in vivo. The mechanism of action of GHRP-6 is unknown, but it probably acts by inhibiting the effects of somatostatin on GH release. The aim of this study was to evaluate the effects of GHRP-6 on GH secretion in patients with hyperthyroidism (n = 9) and in control subjects (n = 9). Each subject received GHRP-6 (1 microg/kg, iv), GHRH (100 microg, iv), and GHRP-6 plus GHRH on 3 separate days. GH peak values (mean +/- SE; micrograms per L) were significantly lower in hyperthyroid patients compared to those in control subjects after GHRH alone (9.0 +/- 1.3 vs. 27.0 +/- 5.2) and GHRP-6 plus GHRH (22.5 +/- 3.5 vs. 83.7 +/- 15.2); a lack of the normal synergistic effect of the association of both peptides was observed in thyrotoxicosis. However, a similar GH response was seen in both groups after isolated GHRP-6 injection (31.9 +/- 5.7 vs. 23.2 +/- 3.9). In summary, we have shown that hyperthyroid patients have a normal GH response to GHRP-6 together with a blunted GH responsiveness to GHRH. Our data suggest that thyroid hormones modulate GH release induced by these two peptides in a differential way.