Three-year experience with access to nationally funded growth hormone (GH) replacement for GH-deficient adults.

OBJECTIVE: Treatment of growth hormone (GH)-deficient adults with GH has been shown to improve a range of metabolic abnormalities and enhance quality of life. However, the results of access to nationally funded treatment have not been reported. DESIGN: Retrospective case series auditing nationally funded treatment of defined GH-deficient adults in New Zealand, with carefully designed entry and exit criteria overseen by a panel of endocrinologists. PATIENTS: Applications for 201 patients were assessed and 191 approved for funded treatment over the initial 3 years since inception. The majority had GH deficiency following treatment of pituitary adenomas or tumours adjacent to the pituitary. RESULTS: After an initial 9-month treatment period using serum IGF-I measurements to adjust GH dosing, all patients reported a significant improvement in quality of life (QoL) score on the QoL-AGHDA(®) instrument (baseline (95%CI) 19 (18-21), 9 months 6 (5-7.5)), and mean serum IGF-I SD scores rose from -3 to zero. Mean waist circumference decreased significantly by 2.8 ± 0.6 cm. The mean maintenance GH dose after 9 months of treatment was 0.39 mg/day. After 3 years, 17% of patients had stopped treatment, and all of the remaining patients maintained the improvements seen at 9 months of treatment. CONCLUSION: Carefully designed access to nationally funded GH replacement in GH-deficient adults was associated with a significant improvement in quality of life over a 3-year period with mean daily GH doses lower than in the majority of previously reported studies.

Comparison of two low-dose calcium infusion schedules for localization of insulinomas by selective pancreatic arterial injection with hepatic venous sampling for insulin.

OBJECTIVE: Localization of small insulinomas may be difficult. Selective pancreatic arterial injection of calcium with hepatic venous insulin measurement (SACST) has been used for this purpose, but can rarely cause hypoglycaemia. Two low-dose concentrations of calcium, 0·25 and 0·1 of the usual concentration used for the test, have been compared for sensitivity of localization and safety. DESIGN: Selective pancreatic arterial injection of calcium with hepatic venous insulin measurement was performed at calcium concentrations of 0·0025 (Protocol A) and 0·00625 (Protocol B) mEq calcium per kg. The standard concentration is 0·025 mEq/kg. PATIENTS: Twenty one successive patients with biochemical evidence of insulinoma were studied. RESULTS: Using surgical localization as the gold standard, Protocol A had a sensitivity of 91% and Protocol B 75% for correct localization. The false-positive localization rate was 16%. No hypoglycaemia was observed. These results compare favourably with published data using the standard calcium concentration. Selective pancreatic arterial injection of calcium with hepatic venous insulin measurement was superior to localization by noninvasive imaging; in seven cases, SACST was correct when conventional imaging was negative (five) or false positive (two). CONCLUSION: Low concentrations of calcium are effective and safe when performing SACST for localization of insulinoma.

Excess mortality in acromegaly.

BACKGROUND: Increased production of growth hormone (GH) and insulin-like growth factor-I (IGF-I) in patients with acromegaly is associated with a twofold increase in mortality compared with the general population. The range of standardised mortality rates in various studies ranges from 1.2 to 3.6. PREDICTORS OF MORTALITY: Multivariate analysis has indicated that post-treatment serum GH levels and, in a number of studies, serum IGF-I levels are the most powerful predictors of outcome. Normal IGF-I concentrations and random GH levels <2.5 microg/l measured by polyclonal radioimmunoassay result in optimal outcome. Other factors adversely influencing mortality include hypertension and a long interval between onset of the disorder and diagnosis. CONCLUSIONS: Analysis of recent reports suggests that adoption of treatment guidelines with appropriate post-treatment target ranges for GH and IGF-I, together with the availability of newer methods to control GH oversecretion, has significantly improved patient outcomes.

Serum IGF-I levels are similar in Samoan, Maori and European populations despite differences in body composition.

OBJECTIVE: To determine if serum IGF-I concentrations are similar in healthy adult subjects from the Samoan, Maori and European populations in New Zealand. DESIGN: Serum IGF-I concentration was measured in 75 healthy adults, aged 18-50 years, of Samoan (n=23), Maori (n=22) and European (n=30) descent. Body composition was assessed using standard anthropomorphic measures. In addition all subjects had body composition assessed by Dual energy X-ray absorptiometry (DXA). RESULTS: Weight, body mass index (BMI), and fat mass were significantly greater in Maori and Samoan subjects than European subjects (ANOVA p=0.006, p=0.0003, p=0.03, respectively). However, serum IGF-I concentration was similar between the groups (European 186.8 SEM 14.9 microg/l, Maori 204.8 SEM 17.1 microg/l, Samoan 180.0 SEM 17.5 microg/l, p=0.58). IGF-I levels were similar between ethnic groups after adjustment (ANCOVA) for age, sex or BMI (p=0.5) or age, sex and fat mass (p=0.44). In multivariate analysis the only independent predictor of IGF-I was age (p<0.001) and explained 22% of the variance in IGF-I level. CONCLUSIONS: Serum IGF-I concentrations were similar in Maori, Samoan and European population groups in New Zealand, despite significant differences in anthropomorphic variables and body composition.

Correlation between hormone binding and growth response of rat mammary tumor.

Dimethylbenzanthracene-induced rat mammary tumors were defined as either prolactin responsive or prolactin independent on the basis of growth response to prolactin administration. There was no difference in tumor binding of prolactin between the two groups when tumors were biopsied before treatment. Prolactin binding was, however, significantly higher in responding tumors when biopsies were obtained following treatment. By contrast, when tumors were defined as responsive or independent on the basis of response to suppression of serum prolactin with bromoergocryptine, there was significantly higher prolactin binding in the responsive than in the independent group both before and after treatment. During serial treatment with prolactin followed by bromoergocryptine, there was a progressive decline in prolactin binding to tumor biopsies, particularly in prolactin-independent tumors. Prolactin binding to pretreatment tumor biopsies thus did not predict which tumors would respond to administration of prolactin but, for the total group, did indicate tumors likely to regress with prolactin withdrawal. However, the correlation between prolactin binding and tumor regression following hormone withdrawal was not sufficiently strong to permit reliable prediction of behavior for individual tumors. Prolactin-independent growth was associated with decreased prolactin binding to tumor tissue, particularly following manipulation of serum prolactin levels.

Regulation of insulin binding to human mammary carcinoma.

In vitro binding of labeled insulin was measured in crude membrane fractions of tumor and fat obtained at the time of breast cancer surgery in 23 women. There was significant insulin binding in 22 of 23 tumor specimens and in all 23 fat samples. High-affinity binding sites were present in tumors [Ka = 1.38 +/- 0.88 (S.E.) x 10(9) M-1 and adjacent fat membranes (Ka = 1.12 +/- 0.15 x 10(9) M-1]. The level of insulin binding was not related to either estrogen receptor status or tumor histological grade. There was a significant negative correlation between insulin binding to fat membranes and fasting insulin levels. In contrast, there was no significant relationship between insulin binding to tumor tissue and serum insulin levels, suggesting the loss of the capacity to "down-regulate" insulin-binding sites by breast tumor cells. The absence of this ability to regulate insulin-binding capacity could result in an increased sensitivity of breast tumor cells to the stimulatory effects of insulin.

Hormone binding by human mammary carcinoma.

The specific binding of labeled porcine insulin, human prolactin, and human growth hormone was studied in 63 human breast tumors and 15 nonmalignant breast tissues. Most (90%) of the tumors demonstrated significant binding of insulin, as did 80% of nonmalignant tissues. Autoradiographic studies indicated that insulin bound dominantly to tumor cells, rather than to fat and fibrous tissue contained within tumors. Specific binding of prolactin and growth hormone of greater than 1% was seen in 20 and 12% of tumors, respectively, and one tumor studied in detail showed a small amount of saturable, high-affinity prolactin binding. The affinity of binding of insulin and prolactin to tumor was similar to that seen in target tissues in subprimate species (Kd = 4 X 10(-10) M), but the prolactin-binding capacity in the one tumor studied in detail was very low (10 fmoles/mg membrane protein), compared with prolactin-responsive experimental mammary carcinoma.

Abnormal insulin-receptor down regulation and dissociation of down regulation from insulin biological action in cultured human tumor cells.

The sensitivity of insulin receptors to down regulation by insulin has been measured in cultured human tumor cells (breast tumor cell lines MCF-7, T-47D, and colon tumor cell line HCT-8). Insulin receptors on breast tumor cells were resistant to down regulation (15-17% maximum loss of insulin binding after 4 h exposure to 170 nM insulin). HCT-8 cells were sensitive to down regulation after 4 h exposure to 3.8 nM insulin, but the extent of down regulation then lessened at higher concentrations of insulin. This paradoxical behavior was associated with increasing affinity of insulin receptors for insulin following exposure to hormone. Insulin-stimulated [3H]leucine incorporation into protein was measured in parallel with studies of receptor regulation to assess the effect of preexposure of cells to insulin on cell metabolism. Maximum down regulation of receptors in all three types of tumor cell by prior exposure to insulin did not significantly alter the responsiveness of any of the cell lines to insulin. Thus insulin receptor down regulation is abnormal in these tumor lines compared with reported studies in normal cells, and this may contribute a metabolic advantage to these malignant cells over normal tissues.

Insulin receptor regulation in cultured human tumor cells.

Insulin binding to monolayer cell cultures of human fibroblasts, human colon carcinoma (HCT-8, HT-29), human breast carcinoma (MCF-7, T-47D), and melanoma (MM-96) was measured using 125I-insulin. Binding was time and temperature dependent in all cell lines, and only one cell line (MM-96) degraded 125I-insulin. High-affinity insulin-binding sites (Kd = 1.4 X 10(-9) M to 0.4 X 10(-10) M) were detected in all cell lines, and insulin-binding capacity ranged from 0.6 to 14 fmol/10(6) cells. Receptor down-regulation was studied by exposing cells to increasing concentrations of unlabeled insulin, dissociating surface-bound insulin and measuring residual receptors by 125I-insulin uptake. Exposure of tumor cells to greater than 10(-6) M insulin for 2 hr at 37 degrees led to a decrease in the number of insulin binding sites in MM-96 and colon cell lines only, with maximum down-regulation ranging from 58% (MM-96) to 88% (HCT-8) receptor loss. The decrease in insulin binding was due to a decreased number of receptors per cell with no change in affinity. Monolayers exposed to 1.7 X 10(-5) M unlabeled insulin for 7 hr at 37 degrees invariably showed greater than 50% receptor loss. However, monolayers exposed to 1.7 X 10(-8) M unlabeled insulin for 7 hr at 37 degrees showed less marked (0 to 39%) down-regulation. In comparison, human fibroblasts showed 57% receptor loss after exposure to 3.5 X 10(-9) M unlabeled insulin for 7 hr. Thus, markedly supraphysiological concentrations of insulin are required to down-regulate insulin receptors in tumor cell lines compared with normal cells. This suggests a tumor-associated resistance to receptor down-regulation.

Progesterone and estrogen receptors as prognostic variables in breast cancer.

Estrogen receptor (ER) and progesterone receptor (PR) levels have been measured in 374 tumors from patients with primary breast cancer and compared with axillary nodal status and other patient variables to determine their relationship to prognosis. Nodal status reliably predicted disease-free interval and overall survival, and both ER and PR status predicted overall survival both individually and within node-positive and node-negative subgroups. PR but not ER status was also able to predict disease-free survival both overall and in the node-positive subgroup. When the two receptor measurements were used in combination, a group of receptor-negative, (ER- and PR-negative), node-negative patients were identified with a significantly worse survival than that for an ER- and PR-positive group of node-positive patients. It is apparent that receptor status provides useful prognostic information in patients with early breast cancer and that ER and PR assays used in combination identify a subgroup of node-negative patients with poor prognosis who are likely to benefit from adjuvant therapy following mastectomy.

Seasonal change in the concentration of progesterone receptor in breast cancer.

There are conflicting reports of seasonal changes in steroid hormone receptor levels in breast cancer tissue. Estrogen receptor and progesterone (PR) receptor levels from 1132 tumors were thus grouped according to month of initial tumor detection or month of tissue sampling/surgery. There was a significant circannual variation in the mean monthly PR receptor concentration in patients grouped according to month of tissue sampling/surgery with peak PR levels in April (late summer-early autumn) and nadir values in August and September (late winter-early spring). There was no significant cyclic variation in estrogen receptor values. A significant annual variation in tumor PR concentration was also seen when receptor levels from individual tumors were grouped according to month of initial tumor detection, with peak PR levels found in January and February. The time interval between tumor detection and biopsy/surgery was 3.3 +/- 5.3 months (mean +/- SD) which was close to the interval between the peak PR concentration expressed by month of tumor detection compared with month of tissue sampling for receptor assay. There was also a significant seasonal variation in the month of initial tumor detection, with peak detection occurring in December (summer). The close synchrony between month of maximum tumor detection and month of peak PR concentration suggests that seasonal changes in detection of breast cancer may in part relate to seasonal changes in hormone responsiveness within tumor tissue.

Effect of fosinopril on cardiac and metabolic parameters in patients with NIDDM.

OBJECTIVE: To determine whether the angiotensin-converting enzyme (ACE) inhibitor fosinopril can favorably alter cardiac function in non-insulin-dependent diabetes mellitus NIDDM) patients who have either normal blood pressure (BP) or mild, untreated hypertension. RESEARCH DESIGN AND METHODS: Fifty-five NIDDM subjects with normal BP or mild, untreated hypertension were randomized to treatment with the ACE-inhibitor fosinopril or placebo for 6 months in a randomized, double-blind trial to determine the effect of fosinopril on echocardiographic measurements. RESULTS: Left ventricular mass index (LVMI) fell by 6.5 +/- 4.7% (mean +/- SD) with fosinopril and increased by 8.6 +/- 3.5% during placebo treatment (P < 0.02), and isovolumic relaxation time improved significantly in those with elevated baseline levels (P = 0.02). Systolic BP fell significantly, but this did not correlate with the change in LVMI, suggesting a possible direct action of fosinopril on the heart. CONCLUSIONS: Fosinopril appears to have significant cardiac benefits in patients with NIDDM who have normal or mildly elevated BP. These benefits are achieved without adversely affecting renal status and without impairing metabolic control of diabetes.

Low thyroxine levels in some hyperprolactinemic patients due to dopaminergic suppression of thyrotropin.

The serum free T4 index (FT4I) was at or below the lower limit of normal in 8 of 55 unselected patients with hyperprolactinemia. Serum levels of T3 were normal and none of the patients had clinical evidence of hypothyroidism. In patients with low FT4I the serum TSH was within the normal range and TSH was released normally after administration of TRH, indicating normal pituitary TSH reserve. Serum TSH also increased after administration of the dopamine antagonist domperidone. The TSH response to domperidone was significantly greater in the hyperprolactinemic group with low FT4I compared with either normal subjects or hyperprolactinemic patients with normal FT4I, suggesting that depression of FT4I was due to increased dopaminergic activity. Administration of the dopamine antagonist metoclopramide for 4 days led to a supranormal rise in FT4I in 3 of 5 patients with low FT4I. Thus, a minority of hyperprolactinemic patients have a low FT4I which appears due to excessive hypothalamic production of dopamine.

Comparison of the redox bioassay with other assays for luteinizing hormone.

The cytochemical (redox) bioassay for LH has been compared with established LH assays. Measurements made by redox bioassays were considerably lower than those made by radioimmunoassay in human female plasma samples obtained at mid-cycle. There was no apparent relationship between measurements on incubation media from cultures of sheep pituitary glands made by redox bioassay and the ovarian ascorbic acid depletion (OAAD) assay. After polyacrylamide gel electrophoresis of a crude extract of a human pituitary gland, redox LH measurements were lower than those of the OAAD assay and radioimmunoassay in the cathodal segments of the gel. By contrast, there was reasonable agreement between LH measurements made by radioimmunoassay and redox assay in cathodal fractions from gel electrophroesis of a purified pituitary LH preparation. Follicle-stimulating hormone, and the alpha- and beta-subunits of LH depressed the response of intact LH in the redox assay; this might explain the relatively low levels of LH measured by redox assay in some of the experiments described. Which type of assay best reflects the biological activity of LH in man remains to be determined.

Myocardial infarction is inversely associated with plasma 25-hydroxyvitamin D3 levels: a community-based study.

The relation between the plasma level of 25-hydroxyvitamin D3, the main metabolite of sun-induced vitamin D, and myocardial infarction (MI) was investigated in a community-based case-control study. Some 179 MI patients presenting to hospital within 12 hours of the onset of symptoms were individually matched with controls by age, sex and date of blood collection. MI patients had significantly lower mean 25-hydroxyvitamin D3 levels than controls (32.0 versus 35.5 nmol/L; p = 0.017), with the case-control differences being greatest in winter and spring. The relative risk of MI for subjects with 25-hydroxyvitamin D3 levels equal to or above the median was 0.43 (95% confidence limits = 0.27, 0.69) compared to subjects below the median. The decrease in MI risk associated with raised vitamin D3 levels was observed in all seasons. These results provide support for the hypothesis that increased exposure to sunlight is protective against coronary heart disease.

Long-term treatment outcome in acromegaly.

A number of groups have developed guidelines to indicate whether an individual with acromegaly has been cured by treatment. However, studies to date do not provide a robust definition of biochemical remission of the disorder based on correlation with long-term outcome. Available data suggest that those with a random serum growth hormone (GH) level of <2.5 microg/l, or a glucose-suppressed GH level of <1 microg/l following treatment have mortality figures indistinguishable from the general population. However, the confidence limits for these mortality estimates are quite wide. It remains possible that growth hormone levels lower than 1 microg/l for random samples, or even lower when using ultrasensitive GH assays, may indicate superior outcome, but this remains to be confirmed. There are limited data relating serum insulin-like growth factor-I (IGF-I) levels to outcome, although normalisation of serum IGF-I clearly improves outcome compared with continued elevation of measurements after treatment. Current evidence suggests that a post-treatment random serum GH <2.5 microg/l and a normal serum IGF-I value defines biochemical cure. Available data suggest that achieving similar growth hormone levels after treatment also reduces the prevalence of chronic complications of the disorder, which is subsequently reflected in improved mortality.

Criteria for cure in acromegaly: report of a case apparently cured in which persisting tumor was found at autopsy.

A 49-year-old man with acromegaly underwent the apparently complete removal of a pituitary microadenoma by the transsphenoidal route. There was complete remission of the biochemical abnormalities for 2 1/2 years, with basal plasma growth hormone (GH) levels of less than 1 ng/ml and normal somatomedin levels. The patient then died after the rupture of a cerebral aneurysm. Serial sections of the pituitary fossa showed persistent tumor with a volume of about 6% of the remaining normal gland. It is concluded that current endocrine tests are limited in their ability to detect residual GH-secreting tumor. Their sensitivity is likely to depend on the mass of tumor and on the GH secretion rate. Predictions of long term cure based on these tests are only tentative.

Measurement of human IGF-II using Sephacryl extraction: a rapid and reliable assay method.

Measurement of insulin-like growth factor II (IGF-II) in human serum is complicated by the presence of IGF binding proteins and usually involves cumbersome extraction procedures followed by radioimmunoassay. We have utilized an extraction process developed for measuring insulin-like growth factor II in ovine serum using Sephacryl HR100, and have applied this to the extraction of human samples followed by radioimmunoassay for human IGF-II. The assay yielded 98% recovery of unlabelled IGF-II, parallelism between dilutions of eluate and the standard curve, complete removal of binding proteins and near-complete removal of IGF-I, and intra- and interassay coefficients of variation of 5% and 9%, respectively. The normal range for serum IGF-II in women was 490-1056 micrograms/L, and IGF-II levels were positively correlated with serum concentrations of insulin-like growth factor binding protein-3 (IGFBP-3) but not with IGF-I levels. Mean serum concentrations of IGF-II were reduced below normal in a number of hypopituitary patients and children with short stature and IGF-II concentrations in these subjects correlated positively with IGF-I and IGFBP-3. In acromegalic patients IGF-II levels were usually normal and were negatively correlated with IGF-I concentrations. From our experience with the above results the present assay appears particularly suitable for clinical measurements and research projects where high sample throughput is required.

Zoladex treatment of symptomatic prostatic carcinoma.

The depot LH-RH agonist Zoladex was used to treat 38 patients with previously untreated symptomatic stage D2 prostate carcinoma. Side effects were minimal and patient acceptability excellent, although temporary tumor flare occurred in 11% of patients. Eighty-four percent experienced subjective improvement and 87% had objective evidence of initial disease stabilization or remission lasting 3 months. Serum levels of gonadotrophin and free testosterone as well as androgens of adrenal origin fell significantly with treatment. Long-term survival to date appears at least as good as that described for conventional endocrine therapy.

Radiological assessment of Paget's disease of bone after treatment with the bisphosphonates EHDP and APD.

The effects of therapy on the osteolytic bone lesions of Paget's disease have been assessed from serial bone radiographs. Changes in the rate of progression of lytic "wedge" lesions were measured and alterations in the texture of lytic "blade" lesions were graded on an empirical scale. Useful matching was possible using standard radiographs, although special care was needed to avoid artefacts from suboptimal positioning, magnification and variation in exposure. Serial radiographs were obtained of 57 lytic blade lesions in 54 patients receiving treatment with the bisphosphonate 1-hydroxyethylidene-1, 1-bisphosphonate (EHDP) and of 20 lesions in 20 patients treated with oral or intravenous 3-amino-1-hydroxypropylidene-1, 1-bisphosphonate (APD). Treatment with EHDP was associated with a significant deterioration in bone texture in 50% of lytic blade lesions, and with healing in only 20%. Deterioration was accompanied by an increase in local bone pain in 17% of these patients. In contrast, significant healing was observed in 17 of 20 lytic lesions (eight wedge, nine blade) within 6 months of beginning a course of intravenous or oral APD. In four of eight patients the progression of a lytic tibial wedge was arrested and in the remaining four the direction of wedge movement was reversed. In two patients the wedge had almost completely "filled in", making measurement difficult. Bone healing was usually accompanied by pain relief, reduction in skin temperature and rapid suppression of the urine hydroxyproline (uHP) into the normal range. However, in four patients who received intravenous APD, repair of lytic bone lesions was observed despite persisting elevation of uHP. These improvements with APD were sustained at 12 months, although in one patient whose biochemical indices were restored to normal the resorption front showed further progression, despite initial temporary reversal. The trends apparent in these short-term studies were also seen in four patients in whom wedge velocities were measured over periods of 6-10 years. These results confirm that after treatment of Paget's disease, bone healing or deterioration can be accurately assessed from serial standard radiographs. Reproducible matching is best achieved by ensuring that all radiographs are taken by the same radiographer. Minor alterations in radiological bone texture provide an important index of drug effect which is not always apparent from measurement of biochemical and other indices.