[Neonatal hypoglycemia in congenital isolated aplasia of the adenohypophysis. A case report]

We report a female newborn with prolonged neonatal hypoglycaemia and vomiting. Endocrinologic studies demonstrated the absence of the anterior pituitary hormones ACTH, STH, LH, FSH, and PRL while TSH basal secretion as well as TSH stimulation were normal at the age of 2 months. Magnetic resonance imaging showed aplasia of the anterior pituitary and a nodular ectopic posterior lobe. Substitution with prednisone resulted in normalization of blood glucose values with clinical improvement of the patient. At the age of 8 months the patient was started on recombinant human growth hormone due to poor growth; with 10 months decrease of thyrotropin secretion resulted in additional thyroxine replacement therapy.

Hypopituitarism secondary to transfacial gunshot wound

Hypopituitarism secondary to penetrating head trauma is extremely rare, and its diagnosis may be delayed for several years. We present a patient who developed hypopituitarism secondary to a transfacial gunshot wound and who experienced damage to the hypophysis secondary to transmission of energy and bullet fragments. The importance of a computerized tomographic scan of the head in facial gunshot wound is discussed.

The effects of prolonged growth hormone replacement on bone metabolism and bone mineral density in hypopituitary adults

OBJECTIVE

Short-term GH replacement in hypopituitary adults increases bone turnover; data on the consequences of longer-term GH treatment are limited. We report on the effects of 12-18 months of GH replacement treatment with biosynthetic human GH on bone metabolism and bone mass in hypopituitary adults.

DESIGN

Patients were studied before and after GH treatment for 12 months (n = 11) and 18 months (n = 27) respectively in an open trial. GH dose was 0.04 +/- 0.01 IU/kg daily.

MEASUREMENTS

Plasma calcium, phosphate and intact PTH concentrations, 24-hour urinary calcium excretion, 3 markers of bone formation (total alkaline phosphatase, osteocalcin and procollagen 1 carboxy terminal peptide (P1CP)) and serum concentration of carboxyterminal cross-linked telopeptide of type 1 collagen (ICTP), as a marker of bone resorption, were measured at 6-month intervals. Lumbar spine and total body bone mineral mass was measured by dual-energy X-ray absorptiometry.

RESULTS

Small increases were observed in plasma calcium and phosphate concentrations at 12 months of GH therapy but the differences at 18 months were not statistically significant. Serum intact PTH concentration did not change. Plasma total alkaline phosphatase increased significantly on GH from 75 +/- 26 to 92 +/- 30 (P < 0.01) and 85 +/- 31 U/I (NS) at 12 and 18 months respectively. Serum osteocalcin increased from 6.5 +/- 3.7 to 15.7 +/- 6.2 (P < 0.0001) and 16.6 +/- 5.7 micrograms/I (P < 0.001) at 12 and 18 months respectively and P1CP increased significantly from 106.0 +/- 47.3 micrograms/I to 165.5 +/- 95.3 (P < 0.0001) and 177.2 +/- 72.2 micrograms/I (P < 0.01) at 12 and 18 months respectively. Plasma ICTP concentration increased also from 3.4 +/- 1.8 to 7.3 +/- 3.4 (P < 0.0001) and 7.0 +/- 2.7 micrograms/I (P < 0.003) at 12 and 18 months of GH therapy respectively. No significant change was observed in total body or lumbar spine bone mass, over the 18 months of GH treatment

CONCLUSIONS

Replacement therapy with GH in hypopituitary adults for 6-18 months produced a sustained increase in bone turnover (both formation and resorption). Bone mass was maintained but did not increase over the study period.

An adult case of neurohypophyseal ectopy presenting ACTH deficiency and partial GH deficiency

A case of ACTH deficiency and partial GH deficiency associated with neurohypophyseal ectopy is described. A 42-year-old woman of short stature was admitted for hypoglycemic coma. The patient had hypocortisolemia, an increase in urinary 17-OHCS after consecutive injections of ACTH-Z, and a low plasma ACTH level which showed no response to corticotropin-releasing factor. This indicated the presence of ACTH deficiency. The plasma GH level showed a blunted response to insulin-induced hypoglycemia, but its response to GRF was preserved. Other hypothalamo-pituitary axes were intact. T1-weighted magnetic resonance imaging demonstrated ectopic neurohypophyseal tissue and a tiny anterior pituitary remnant. ACTH deficiency and partial GH deficiency might have developed as a consequence of pituitary stalk injury and inadequate regeneration of the anterior lobe.

Evaluation and application of a highly sensitive assay for serum growth hormone (GH) in the study of adult GH deficiency

Previous work from our laboratory addressing the diagnosis of GH deficiency in adults showed that RIA measurement of the 24-h integrated GH concentration (IGHC) was unable to discriminate between hypopituitary and age-, sex-, and body mass index-matched normal subjects because of the occurrence of undetectable levels (< 200 ng/L) within both groups. In contrast, full separation was achieved using stimulation by the insulin tolerance test (ITT). The data showed no significant relationship between IGHC and insulin-like growth factor-I (IGF-I) within either group. To determine whether limited sensitivity obscured diagnostic and physiological information, we assessed and modified a commercially available enzyme-linked immunosorbent assay (Elegance GH ELISA, Bioclone Australia) to achieve a high sensitivity (1 ng/L) and applied it to the study of IGHC and the relationship to IGF-I in a study group of 30 normal and 19 subjects with severe organic hypopituitarism. Using this assay, the IGHCs from all subjects were detectable and correlated significantly with detectable values obtained by RIA (n = 24; r = 0.80; P = 0.0001). Mean IGHC in normal subjects was significantly higher than that in hypopituitary subjects (852 +/- 131 vs. 97 +/- 28 ng/L), but the IGHCs from the two groups were not completely separate. Twenty-six percent of hypopituitary subjects had IGHC values within the normal range (111-3454 ng/L). IGHC decreased with age in normal subjects. Age stratification improved the separation, but an overlap remained in the young (< 50 yr old) and old (> 50 yr old) groups. Measurement of 12-h nocturnal IGHC levels improved the separation between hypopituitary and normal subjects in the young subjects only. IGHC was significantly related to IGF-I in hypopituitary (r = 0.59; P = 0.0084) and normal subjects (r = 0.55; P = 0.0017) and in the combined groups (r = 0.64; P = 0.0001). The data show that a sensitive ELISA reliably quantifies IGHC in normal and hypopituitary subjects. IGHCs in hypopituitary patients are lower, but not clearly separated from values in normal counterparts despite their having unequivocally impaired GH responses to ITT. We conclude that 1) IGHC in normal subjects can be reliably defined by sensitive ELISAs; 2) the diagnostic utility of the IGHC does not match the reliability or simplicity of an ITT, and 3) GH is a significant regulator of IGF-I in both normal and reduced states of GH secretion.

Abnormal body composition and reduced bone mass in growth hormone deficient hypopituitary adults

OBJECTIVES

The role of growth hormone in maintaining normal body composition and bone strength in adults has attracted much interest recently. We have assessed body composition and bone mass in GH deficient hypopituitary adults on conventional replacement therapy and compared them with matched controls.

DESIGN AND SUBJECTS

A cross-sectional study of 64 growth hormone deficient hypopituitary adults (29 males and 35 females) on conventional replacement therapy and a large number of healthy control subjects matched for age, sex and body mass index (BMI).

MEASUREMENTS

Skinfold thicknesses at two sites (triceps and subscapular), waist and hip girth circumferences were assessed by standard methods. Body composition was assessed using total body potassium (TBK), bioelectrical impedance analysis (BIA) and dual-energy X-ray absorptiometry (DEXA). Bone mineral mass was assessed at the lumbar spine and the total body by DEXA. Not every patient and control participated in every measurement.

RESULTS

Obesity was common in the hypopituitary patients; BMI (mean +/- SD) was 27.5 +/- 4.6 kg/m2 and body weight was 111.8 +/- 18.5% of the maximal ideal for height (P < 0.001). The sum of subscapular and triceps skinfolds was significantly higher in hypopituitary patients than in controls (men 46 + 15 vs 37 +/- 14 mm, P < 0.05; women 55 +/- 13 vs 47 +/- 17 mm, P < 0.05). Waist to hip circumference ratio was significantly greater in female hypopituitary patients than in matched controls but was not significantly different in men (men 0.94 +/- 0.07 vs 0.91 +/- 0.07, NS; women 0.84 +/- 0.09 vs 0.77 +/- 0.05, P < 0.001). The difference between patients and controls in the sum of skinfolds and the waist to hip ratio were present in non-obese (BMI < 26 kg/m2) subjects (21 patients and 32 controls). TBK corrected for body weight was significantly lower in hypopituitary patients (n = 44) than in controls (n = 31) (men 43.5 +/- 5.6 vs 50.1 +/- 5.9 mmol/kg, P < 0.003; women: 34.0 +/- 3.2 vs 40.6 +/- 5.3 mmol/kg, P < 0.0001). BIA-derived body water content (corrected for body weight) was significantly lower in hypopituitary patients (n = 56) than in controls (n = 57) (0.492 +/- 0.064 vs 0.545 +/- 0.067 l/kg, P < 0.0004). Percentage body fat derived from all the three methods was significantly higher in hypopituitary patients than in normal controls in both sexes (from TBK: men 34.7 +/- 9.4 vs 28.8 +/- 7.0%, P < 0.05; women 37.8 +/- 8.7 vs 30.4 +/- 9.7%, P < 0.01; from BIA: men 29.3 +/- 8.5 vs 23.2 +/- 8.4%, P < 0.01; women 34.6 +/- 8.1 vs 29.3 +/- 9.1% P < 0.01; and from DEXA: men 24.8 +/- 6.8 vs 20.4 +/- 6.1%, P < 0.05; women 38.9 +/- 7.9 vs 32.5 +/- 9.8%, P < 0.01). There was a significant difference between non-obese patients and controls in BIA-derived percentage fat in both sexes and in TBK-derived percentage fat in females only. Bone mineral density (BMD) of the lumbar spine in the L2-L4 region was lower in hypopituitary patients than in controls (men 1.116 +/- 0.129 vs 1.311 +/- 0.131 g/cm2, P < 0.0001; women 1.001 +/- 0.122 vs 1.131 +/- 0.138 g/cm2, P < 0.001). Spine BMD was also reduced in hypopituitary patients compared to the young adult and age and weight matched reference data. Total body BMD was significantly lower in patients than in controls (men 1.186 +/- 0.102 vs 1.250 +/- 0.080 g/cm2, P < 0.05; women 1.080 +/- 0.077 vs 1.149 +/- 0.073 g/cm2, P < 0.005).

CONCLUSIONS

Hypopituitary adults on conventional therapy have abnormal body composition with increased fat content, reduced body water content and reduced bone mineral mass.

Post-heparin plasma lipase activity in hypopituitary adults

Twenty-six hypopituitary patients on conventional replacement therapy were compared with 31 matched normal controls. Plasma lipoprotein lipase (LPL) and hepatic lipase (HL) activities were measured 15 min after a bolus of intravenous heparin (100 IU/kg body weight). Fasting plasma lipids, lipoproteins, glucose and insulin and triceps to subscapular skin fold ratio and waist to hip circumference ratio were also measured. Total and low density lipoprotein cholesterol were significantly higher in patients than in controls. Plasma activity of both LPL and HL was significantly higher in hypopituitary patients than in controls (p < 0.005 and p < 0.04 respectively). When men and women were analysed separately, significant differences between HP patients and controls remained for total cholesterol and LPL in women and for HL in men.

Effect of glucocorticoid replacement therapy on glucose tolerance and intermediary metabolites in hypopituitary adults

BACKGROUND AND OBJECTIVES

Excess impaired glucose tolerance and diabetes mellitus have been reported in hypopituitary adults on conventional replacement therapy including glucocorticoids. We investigated the effect of the glucocorticoid component on glucose tolerance and intermediary metabolites in hypopituitary adults.

DESIGN

A 3-hour 75-g oral glucose tolerance test (OGTT) was performed on two study days, at least one week apart. On one study day, the glucocorticoid replacement morning dose was taken 60 minutes before the OGTT, and on the other it was left until after the OGTT. All other pituitary replacement therapies were kept unchanged on the two study days.

PATIENTS

Eight hypopituitary adults (3 males and 5 females; aged 46-76 years) on conventional replacement therapy were studied. Their duration of hypopituitarism was mean (range) 15 (5-31) years. Their mean body mass index (BMI) was 28.4 (24.1-35.1) kg/m2. Their total daily cortisol dose was 26 (15-30) mg.

MEASUREMENTS

Plasma glucose, insulin, non-esterified fatty acids (NEFA), glycerol and 3-hydroxybutyrate were measured at 30-minute intervals and plasma cortisol levels were measured hourly.

RESULTS

Fasting glucose and insulin concentrations were similar on the glucocorticoid day (GD) and the non-glucocorticoid day (NGD) (glucose (mean +/- SD) 4.9 +/- 0.9 vs 4.4 +/- 0.5 mmol/l; insulin (median (range)) 5 (1-17) vs 2 (1-15) mU/l, respectively). Post-glucose glycaemia was higher on the GD than on the NGD with a significantly higher glucose area under the curve (AUC) (45.0 +/- 8.2 vs 38.9 +/- 11.7 mmol/l h, P < 0.05). Post-glucose insulinaemia was also higher on the GD than on the NGD with significantly higher insulin AUC (270 (47-909) vs 207 (46-687) mU/l h, P < 0.02). Impaired glucose tolerance was found in three patients on the GD, one of whom continued to have impaired glucose tolerance on the NGD. The areas under the curves of NEFA, glycerol and 3-hydroxybutyrate were not significantly different on the two days. On the NGD, plasma cortisol levels were undetectable (< 50 nmol/l) in all patients and on the GD the median (range) peak was 500 (330-740) nmol/l dropping to 125 (60-330) nmol/l at 180 minutes. The difference in glucose AUC between the two days correlated with the maximal plasma cortisol levels (Spearman's p = 0.83, P < 0.01).

CONCLUSIONS

Glucocorticoid replacement therapy taken pre-prandially in hypopituitary adults induces mild elevations in circulating glucose and insulin levels even with acceptable plasma cortisol concentrations. Optimal regimens for glucocorticoid replacement require more study.

Thyrotropin secreting pituitary adenoma associated with hypopituitarism and diabetes insipidus in an adolescent boy

A 13 year-old boy was referred to our hospital because of several months of school performance deterioration, behavioral changes and secondary enuresis. Hyperthyroidism, diabetes insipidus and hypopituitarism due to thyrotropin secreting pituitary macroadenoma were found. Six weeks of therapy with octreotide failed to reduce the serum TSH levels and the tumor size. Transsphenoidal pituitary surgery had a transient effect on serum TSH levels as the patient redeveloped hyperthyroidism with elevated serum TSH levels. Several months had elapsed from the time the patient first presented with the symptoms to the time the diagnosis was made. Thyrotropin secreting pituitary adenoma is a rare cause of hyperthyroidism. Recognizing the signs of the disease might lead to early diagnosis and might improve the prognosis.

Bone turnover and bone mineral density in young adult patients with panhypopituitarism before and after long-term growth hormone therapy

We examined the effects of biosynthetic growth hormone (GH) on biochemical indices of bone turnover and on bone mineral density in a group of GH-deficient adults. Thirteen patients (eight males and five females) aged 24 +/- 5 years (range 16-35) were studied before and 12 and 24 months after GH treatment (0.1 IU.kg-1 day-1, 6 days a week). Serum levels of insulin-like growth factor I (IGF-I), calcitonin, parathyroid hormone, alkaline phosphatase, intact osteocalcin, fasting urinary hydroxyproline/creatinine ratio and bone mineral density (BMD), measured at the lumbar spine by dual-photon absorptiometry, were evaluated. After 12 months of treatment, IGF-I, alkaline phosphatase, osteocalcin and the fasting urinary hydroxyproline/creatinine ratio increased significantly. However, after 24 months of therapy, serum levels of osteocalcin decreased to pretreatment values while IGF-I, fasting urinary hydroxyproline/creatinine ratio and alkaline phosphatase remained elevated significantly. No changes were found in parathyroid hormone and calcitonin plasma levels or in BMD either after 12 or 24 months of treatment. These data demonstrate that GH, at the dosage that we used, activates bone turnover during 24 months of therapy in adults with panhypopituitarism, even if a downward trend for osteocalcin became apparent at 24 months. However, this activation in bone turnover was not accompanied by an increase in BMD. We can hypothesize that GH, at the relatively high dosage used, may stimulate osteoclastic activity to a greater extent than osteoblastic activity. It is probable that the dose of GH replacement therapy in adults plays a key role.

Serum growth hormone-binding protein is unchanged in adult panhypopituitarism

The role of GH in regulating GH-binding protein (GHBP) and GH receptor concentrations in humans is not clear. Studies performed mostly in children and on a minor scale in adults are somewhat controversial. The key question as to whether GHBP levels are altered in hypopituitarism before GH treatment is instituted remains unanswered. In this study, we have selected a severely GH-deficient group of adult patients with panhypopituitarism, acquired as a result of surgery and irradiation of hypothalamic-pituitary tumors, to evaluate the GHBP/receptor status by measuring GHBP activity in plasma. Twenty panhypopituitary patients (8 males and 12 females; age range, 20-74 yr) and 20 age (22-68 yr)- and sex-matched normal subjects were studied. GH deficiency was confirmed by insulin-induced hypoglycemia and arginine infusion tests; the peak GH response was less than 2 micrograms/L. Plasma insulin-like growth factor-I levels were below or in the low normal range (mean +/- SD, 88.3 +/- 53.6 micrograms/L) and were significantly different from insulin-like growth factor-I (IGF-I) levels in the normal group (mean +/- SD, 189 +/- 49.8 micrograms/L; P < 0.01). Plasma GHBP activity, measured using a GH-binding/gel chromatography assay, showed similar values in the GH-deficient group (mean +/- SD, 14.1 +/- 3.83%) and the control group (mean +/- SD, 13.7 +/- 3.79%), with no statistically significant difference. Neither the intra- nor intergroup comparison of GHBP levels according to age and sex showed statistically significant differences or age trends. In the light of these data and considering that GHBP activity in plasma probably reflects the GH receptor status in tissues, we may assume that the GH receptor was unaffected by chronic GH deficiency. These findings also support the previously reported concept that the GHBP/receptor level is a relatively fixed determinant of growth, established individually and independently of GH secretory status in early life, perhaps on a genetic basis.

Clinical and laboratory evaluation of 40 patients with Sheehan's syndrome

Forty patients with typical obstetric history of Sheehan's syndrome were reviewed retrospectively. Together with baseline laboratory values, insulin hypoglycemia test was evaluated in 15 patients, thyrotropin-releasing hormone (TRH) in 27 and luteinizing hormone-releasing hormone (LH-RH) in 7 patients. Baseline hormone values suggested secondary hypothyroidism, hypogonadotropic hypogonadism and hypocortisolemia. According to the results of the anterior pituitary stimulation tests, one patient (6.6%) showed normal cortisol response and one patient (6.6%) showed normal growth hormone response to hypoglycemia. Nine patients (33.3%) who were clinically and biochemically hypothyroid demonstrated adequate TSH response to TRH. None of the patients showed normal prolactin response to TRH. Four out of seven amenorrheic patients (57.1%) had adequate follicle-stimulating hormone and/or LH responses to LH-RH. It has been concluded that isolated anterior pituitary hormone deficiencies may occur in patients with Sheehan's syndrome. Prolactin response to TRH seems the most sensitive screening test for detecting Sheehan's syndrome in patients with typical obstetric history.

The effect of growth hormone replacement on cortisol metabolism and glucocorticoid sensitivity in hypopituitary adults

OBJECTIVE

Growth hormone (GH) replacement therapy in hypopituitary adults is associated with sodium and water retention. The underlying mechanisms are incompletely understood and a possible contribution of altered cortisol metabolism or action has not been evaluated. We have investigated the effect of GH replacement therapy on cortisol metabolism, cortisol binding globulin and in-vitro glucocorticoid sensitivity in a group of adult hypopituitary patients.

DESIGN AND PATIENTS

We studied 19 adult hypopituitary patients (18 adult onset, M:F, 6:13), who were receiving conventional hydrocortisone (16 patients), thyroxine (14 patients), triiodothyronine (1 patient), sex steroid (9 patients), human chorionic gonadotrophin (1 patient) or desmopressin (6 patients) replacement during a 6-month, double blind controlled trial of GH therapy (active:placebo, 8:11) followed by a 6-month open phase of GH (mean dose: 0.2 IU/kg/week, range 0.051-0.27) and after a 6-week washout phase following discontinuation of GH therapy.

MEASUREMENTS

Twenty-four-hour urine free cortisol, cortisol metabolites (CoM), ratio 11-hydroxy/11-oxo CoM (F/E) and ratio 5 alpha/beta tetrahydrocortisol were measured at 6 months, 12 months and after the 6 week washout phase. Serum cortisol binding globulin was measured basally, at 6 months, 12 months and after washout. Glucocorticoid sensitivity was determined in lymphocyte preparations from 8 patients, during GH therapy and after washout, using an in-vitro technique dependent on dexamethasone suppression of phytohaemagglutinin-stimulated thymidine incorporation into DNA. Plasma renin activity and aldosterone were measured after 6-12 months GH therapy and after washout.

RESULTS

After 6 months of GH, in patients on hydrocortisone (n = 9), there were significant decreases in CoM (mean decrement 21%, P < 0.01), F/E (mean decreased from 1.27 to 1.0, P = 0.04; reference range 0.33-1.29) and 5 alpha/5 beta tetrahydrocortisol (mean decreased from 0.67 to 0.48, P = 0.01) and a subsequent increase after washout. Patients not on hydrocortisone (n = 2) demonstrated a normal basal F/E falling by 25% on GH therapy but no change in CoM. During 12 months of GH therapy, patients on hydrocortisone (n = 7) demonstrated a further trend to decrement in CoM (P = 0.09) which reversed after washout (P = 0.04). Urine free cortisol tended to fall during GH therapy and increased significantly following washout after 12 months treatment (P < 0.02). Serum cortisol binding globulin decreased by 20% (P < 0.05) during 12 months GH treatment but remained within the reference range. In-vitro studies demonstrated a trend to reduced glucocorticoid sensitivity on GH therapy; the maximum inhibition of phytohaemagglutinin by dexamethasone tended to be less on GH therapy (P = 0.052) and was also lower than in 29 normal volunteers (P < 0.05). There were no significant changes in plasma renin but there was a small increment in aldosterone in recumbent patients (P = 0.04) during the open phase of GH therapy in the placebo arm.

CONCLUSIONS

GH therapy in hypopituitary adults is associated with an apparent reduction in availability of administered hydrocortisone as measured by urine cortisol metabolites and urine free cortisol. This effect is unlikely to be clinically significant except possibly in ACTH deficient subjects on suboptimal hydrocortisone replacement. The changes in F/E suggest that GH may directly or indirectly modulate the activity of 11 beta-hydroxysteroid dehydrogenase. The apparent decrease in glucocorticoid sensitivity during GH therapy, demonstrated in vitro, merits further investigation.

Corticotropin-releasing factor-binding protein concentrations in plasma of patients with hypothalamic-pituitary-adrenal disorders

Immunoreactive corticotropin-releasing factor-binding protein (CRF-BP) concentrations in human plasma were determined by means of radioimmunoassay for human CRF-BP. CRF-BP antiserum to the C-terminal fragment of human CRF-BP (298-322) was produced, and CRF-BP (298-322) was used as the tracer and the standard. Large amounts of human CRF did not affect measurement of plasma CRF-BP with this radioimmunoassay. The basal plasma CRF-BP concentration in normal subjects was 4.19 +/- 0.57 nmol/L (mean +/- SD). The CRF-BP concentration was low in patients with Cushing's syndrome, except those with preclinical Cushing's syndrome, and high in patients with Addison's disease, hypopituitarism and isolated ACTH deficiency. After surgery, the plasma CRF-BP concentration in patients with Cushing's syndrome rose, peaked, and then decreased to the control level. In patients with Addison's disease, the high plasma CRF-BP concentration decreased to the control level after hydrocortisone replacement, the same as plasma ACTH concentration. These findings suggest that the immunoreactive CRF-BP concentration in human plasma was decreased by glucocorticoids, at least under chronic conditions.

Comparison of adrenocorticotropin and adrenal steroid responses to corticotropin-releasing hormone versus metyrapone testing in patients with hypopituitarism

We compared the responses of ACTH and cortisol (F) to corticotropin-releasing hormone (CRH) administration (ovine 1 microgram/kg i.v. bolus) with the responses of urinary 17-OH corticosteroids (17-OHCS) and serum deoxycorticosterone (DOC) to metyrapone administration (450 mg/m2/dose every 4 h x seven doses) in 16 hypopituitary patients. Glucocorticoid therapy for these patients was withheld for a minimum of 3 wk before testing. The CRH test was performed 3 d before or 3 wk after the metyrapone test was used to diagnose the ACTH reserve status. In nine ACTH-intact hypopituitary patients (post-metyrapone 17-OHCS > 12.2 mumol/m2/d; DOC > or = 11.5 nmol/L), the peak F (497-773 nmol/L) and ACTH (5.2-22 pmol/L) responses to CRH stimulation were similar to those of normal subjects (F peak = 554-993 nmol/L and ACTH peak = 6-25 pmol/L at 15-60 min). In one patient with partial ACTH deficiency (postmetyrapone 17-OHCS = 10.5 mumol/m2/d; DOC = 6 nmol/L), the peak F response was low and delayed (246 nmol/L at 180 min) and the peak ACTH response was normal (7 pmol/L). Six severely ACTH-deficient patients (postmetyrapone 17-OHCS < 5.4 mumol/m2/d; DOC < or = 3.4 nmol/L) had a low F response at 15-90 min in all, with a delayed rise in three at 120-180 min in response to CRH administration, whereas ACTH responses were variable: absent or low, normal, delayed, or persistently exaggerated. In conclusion, the CRH-stimulated F response pattern in hypopituitary patients was comparable to the urinary 17-OHCS and serum DOC response to metyrapone administration.(ABSTRACT TRUNCATED AT 250 WORDS)

Congenital hypopituitarism as part of suprasellar dysplasia. A case report

Congenital hypopituitarism may be due to hypothalamic failure. The case presented below belonged to this category. In addition, the demonstration of absent septum pellucidum placed this case in the category of suprasellar dysplasia. The patient was 21 years old, with primary amenorrhea and lack of development of secondary sex characteristics. The laboratory findings confirmed the diagnosis of hypothyroidism, hypocortisolism, hypogonadotropism, hyperprolactinemia and normal growth hormone. Stimulation studies revealed a subnormal response of cortisol to adrenocorticotrophic hormone stimulation, subnormal response of follicle stimulating hormone and luteinizing hormone to gonadotropin releasing hormone stimulation, normal response of prolactin to thyrotropin releasing hormone stimulation and exaggerated response of thyroid stimulating hormone to thyrotropin releasing hormone stimulation. The patient was treated with thyroid supplementation. Magnetic resonance imaging showed a hypoplastic infundibulum, ectopic neurohypophysis, small anterior pituitary gland and absent septum pellucidum. Congenital hypopituitarism may be part of a large spectrum of midline brain abnormalities.

Counter-regulatory hormone responses to insulin-induced acute hypoglycemia in hypopituitary patients

Patients with hypopituitarism are predisposed to fasting hypoglycemia and are considered unusually sensitive to insulin-induced acute hypoglycemia. However, whether impaired response of counter-regulatory hormones, such as glucagon, epinephrine (E), and nor-epinephrine (NE) contribute to the susceptibility to acute hypoglycemia in hypopituitary patients has not been systematically evaluated. Therefore, we compared counter-regulatory hormone responses to insulin-induced acute hypoglycemia in 9 patients with hypopituitarism who were off hormone replacement therapy and 13 normal healthy subjects. All subjects received aa prime-continuous intravenous infusion of insulin (0.1 Unit/kg body weight.h) till plasma glucose declined to less than 2.5 mmol/l or occurrence of hypoglycemic symptoms. All normal subjects and 7 out of 9 hypopituitary patients recovered spontaneously from hypoglycemia. Two hypopituitary patients with hypothalamic pathology however needed intravenous glucose, glucagon and hydrocortisone to assist recovery from hypoglycemia. Overall, patients with hypopituitarism showed a slower rate of recovery of plasma glucose after hypoglycemia than normal subjects (0.78 +/- 0.33 mmol/l.h vs. 1.72 +/- 0.15 mmol/l.h, respectively; p = 0.02). The responses of key counter-regulatory hormones, glucagon, E and NE, to hypoglycemia however were essentially similar in both the groups. We conclude that the lack of cortisol (secondary to ACTH deficiency) and GH in hypopituitary patients may be primarily responsible for the slow recovery of plasma glucose after acute hypoglycemia; and plasma glucagon, E, and NE responses are not impaired.

Diagnosis of growth-hormone deficiency in adults

There is no consensus as to the most appropriate method of diagnosing growth-hormone (GH) deficiency in adults. We have evaluated the relative diagnostic merits of measuring peak GH response to insulin-induced hypoglycaemia (insulin tolerance test), mean 24 h GH concentration derived from 20 min sampling, serum insulin-like growth factor I (IGF-I) concentrations, and serum IGF binding protein 3 (IGFBP-3) concentrations. These tests were undertaken in 23 patients considered GH deficient from extensive organic pituitary disease, and in 35 sex-matched normal subjects of similar age and body-mass index. Hypopituitary subjects had significantly lower stimulated peak GH, mean 24 h GH, IGF-I, and IGFBP-3 concentrations than normal subjects. The ranges of stimulated peak GH responses were clearly separated between the hypopituitary (< 0.2-3.1 ng/mL) and normal (5.3-42.5 ng/mL) groups, but mean 24 h GH, IGF-I, and IGFBP-3 concentrations overlapped. Mean 24 h GH concentrations were below assay sensitivity in 80% of hypopituitary subjects and 16% of normal subjects. 70% and 72%, respectively, of the IGF-I and IGFBP-3 values in hypopituitary subjects were within the range for normal subjects. We conclude that GH deficiency in adults is most reliably identified by stimulatory testing, and that IGF-I and IGFBP-3 are poor diagnostic tests of adult GH deficiency.

Hypernatremic myopathy

We describe a 21-year-old man presenting with proximal muscle weakness associated with hypernatremia. His manifestations other than muscle weakness included dry skin, loss of axillary and pubic hair, decreased libido and loss of thirst sensation. His serum sodium level was elevated to 169-171 mEq./l but all other electrolytes were normal. In addition, serum CK was elevated and an EMG study showed myogenic changes. Endocrinological studies revealed hypothalamic hypopituitarism, while MRI revealed a suprasellar mass. A partial correction of hypernatremia led to an immediate recovery of the muscle weakness as well as a normalization of both the serum CK level and EMG findings, suggesting a direct association between the muscle weakness and hypernatremia. The phosphocreatine/inorganic phosphorus (PCr/Pi) ratios in the resting calf muscle, obtained using 31P magnetic resonance spectroscopy (MRS), were very low during the state of muscle weakness, while they returned to nearly normal values after clinical improvement, suggesting that the muscle weakness in hypernatremic state was caused by a depletion of the intramuscular energy stores, probably due to an overworking Na-K pump to correct the intracellular electrolyte imbalance.

Familial congenital hypopituitarism with central diabetes insipidus

Congenital hypopituitarism (CH) presenting with central diabetes insipidus is typically associated with midline facial deformities or ophthalmological abnormalities. We present three brothers with CH and central diabetes insipidus not associated with any of these predisposing conditions. All three subjects presented with clinical features typical for CH (neonatal hypoglycemia, short stature, protruding forehead, and microgenitalia). All had hypoplastic genitalia indicating in utero gonadotropin deficiency, and all had complete GH deficiency. One represented low levels of thyroid hormones and TSH, indicating central hypothyroidism. Water deprivation examination in two of the brothers demonstrated complete arginine vasopressin deficiency in one and partial deficiency in the other. Magnetic resonance imaging indicated absence of the pituitary stalk, severe hypoplastic anterior pituitary in all three brothers, and absence of any posterior pituitary gland in two of the three. The other sibling had an ectopic posterior pituitary. This first report of familial CH with central diabetes insipidus may represent a previously unknown midline anomaly and provide new insights into the genetic control of pituitary and hypothalamic development.

Growth hormone-binding protein levels: studies of children with short stature

A high-affinity growth hormone-binding protein (GHBP) in serum is derived from the extracellular domain of the GH receptor. In an attempt to investigate the differences in GHBP levels in various conditions of poor growth, we measured GHBP levels by two methods--an Ultrogel chromatographic technique and a ligand-mediated immunofunctional assay (LIFA). The following three groups of children were studied: Turner's syndrome (n = 7), idiopathic and/or familial short stature ([ISS] n = 15), and organic or idiopathic hypopituitarism (n = 19). All groups were similar in age (Turner's syndrome, 10.1 +/- 0.9 years; ISS, 10.0 +/- 0.7; hypopituitarism, 11.5 +/- 1.0) and height SEM score (Turner's syndrome, -2.9 +/- 0.3; ISS, -3.0 +/- 0.4; hypopituitarism, -2.3 +/- 0.4). Their values were compared with those values of GHBP in healthy controls of similar age. Immunofunctional assay values for GHBP were as follows: Turner's syndrome, 235.4 +/- 26.0 pmol/L; ISS, 122.4 +/- 11.0; and hypopituitarism, 157.1 +/- 23.0. These results were significantly different in subjects with ISS and hypopituitarism as compared with a group of healthy controls between the ages of 9 and 12 years (N = 255; GHBP = 287.9 +/- 10.9 pMol/L; P < .001 compared with both ISS and hypopituitarism). Similar changes were found using Ultrogel chromatography. This difference in GHBP levels is still significant even when more stringent criteria are applied to define hypopituitarism (ie, peak GH responses to stimuli < 6.0 ng/mL, instead of < or = 10 ng/mL originally).(ABSTRACT TRUNCATED AT 250 WORDS)

Academic achievement and psychological adjustment in short children. The National Cooperative Growth Study

Limited information is available on the educational and behavioral functioning of short children. Through 27 participating medical centers, we administered a battery of psychologic tests to 166 children referred for growth hormone (GH) treatment (5 to 16 years) who were below the third percentile for height (mean height = -2.7 SD). The sample consisted of 86 children with isolated growth-hormone deficiency (GHD) and 80 children with idiopathic short stature (ISS). Despite average intelligence, absence of significant family dysfunction, and advantaged social background, a large number of children had academic underachievement. Both groups showed significant discrepancy (p < .01) between IQ and achievement scores in reading (6%), spelling (10%), and arithmetic (13%) and a higher-than-expected rate of behavior problems (GHD, 12%, p < .0001; ISS, 10%, p < .0001). Behavior problems included elevated rates of internalizing behavior (e.g., anxiety, somatic complaints) and externalizing behavior (e.g., impulsive, distractable, attention-seeking). Social competence was reduced in school-related activities for GHD patients (6%, p < .03). The high frequency of underachievement, behavior problems, and reduced social competency in these children suggests that short stature itself may predispose them to some of their difficulties. Alternately, parents of short, underachieving children may be more likely to seek help. In addition, some problems may be caused by factors related to specific diagnoses.