Simple and practical screening approach to identify HIV-infected individuals with depression or at risk of developing depression

OBJECTIVES

Studies have shown that depression and other mental illnesses are under-diagnosed among HIV-infected individuals. The aim of this study was to evaluate the use of mental health history and questionnaire-based screening instruments to identify HIV-infected individuals at risk of depression.

METHODS

The Beck Depression Inventory II (BDI-II) was used to assess the prevalence and severity of depressive symptoms among HIV-infected individuals attending two out-patient clinics in Denmark. HIV-infected individuals with a BDI-II score ≥ 20 were offered a clinical evaluation by a consultant psychiatrist. The BDI-II score was compared to the outcome of mental health history review, and to results obtained using the European AIDS Clinical Society (EACS) two-item depression screening tool.

RESULTS

A total of 501 HIV-infected individuals were included in the study. Symptoms of moderate/major depression (BDI-II score ≥ 20) were observed in 111 patients (22%); 65 of these patients consulted a psychiatrist, of whom 71% were diagnosed with a co-existing disorder. The BDI-II score was compared to the outcome of a mental health history review, and to results obtained using the European AIDS Clinical Society (EACS) two-item depression screening tool. The two questions showed a sensitivity and specificity of 95% and 68%, respectively, for diagnosis of current depression or risk of depression. A previous psychiatric history and substance abuse were independently associated with an increased risk of depression.

CONCLUSIONS

We suggest that the mental health of HIV-infected individuals should be reviewed and a "risk-flag" three-step approach should be used (1) to screen routinely with the two verbal questions suggested by the EACS, (2) to identify whether there is a risk of depression and then screen with the BDI-II, and (3) to identify whether there is still a risk and then perform a full evaluation and obtain an accurate psychiatric diagnosis by a psychiatrist.

Vascular Disease and Trajectories of Late-life Major Depressive Disorder in Secondary Psychiatric Care

Objectives

To examine 5 years trajectories of secondary-treated late-life major depressive disorder (MDD), and evaluate whether pre-existing cerebrovascular disease and related risk factors are associated with more severe trajectories of late-life MDD.

Methods

Data were obtained from Danish registers. The sample included 11,184 adults ≥ 60 at index MDD diagnosis. Trajectories of in or outpatient contact at psychiatric hospitals for MDD over the 5 years period following index MDD diagnosis were modeled using latent class growth analysis. Risk factors included cerebrovascular disease, cardiovascular disease, hypertension, diabetes, and vascular dementia defined based on hospital diagnoses and prescription medications, demographic characteristics and characteristics of the index MDD diagnosis.

Results

The final model included classes with consistently low (66%), high decreasing (19%), consistently high (9%) and moderate fluctuating (6%) probabilities of contact at a psychiatric hospital for MDD during the 5 year period following the index MDD diagnosis (Fig. 1). Older age, greater severity, inpatient treatment and > 12 antidepressant prescriptions within 5 years of the index MDD diagnosis predicted membership in more severe trajectory classes. Cerebrovascular disease and related risk factors were not associated with trajectory class membership.

Conclusions

A substantial proportion (34%) of individuals diagnosed with MDD in late-life require specialized psychiatric treatment for extended periods of time. We found no evidence that cerebrovascular disease or related risk factors predicted course trajectories in secondary-treated late-life MDD.

Disclosure of interest

The authors have not supplied their declaration of competing interest.

Translational mixed-effects PKPD modelling of recombinant human growth hormone - from hypophysectomized rat to patients

BACKGROUND AND PURPOSE

We aimed to develop a mechanistic mixed-effects pharmacokinetic (PK)-pharmacodynamic (PD) (PKPD) model for recombinant human growth hormone (rhGH) in hypophysectomized rats and to predict the human PKPD relationship.

EXPERIMENTAL APPROACH

A non-linear mixed-effects model was developed from experimental PKPD studies of rhGH and effects of long-term treatment as measured by insulin-like growth factor 1 (IGF-1) and bodyweight gain in rats. Modelled parameter values were scaled to human values using the allometric approach with fixed exponents for PKs and unscaled for PDs and validated through simulations relative to patient data.

KEY RESULTS

The final model described rhGH PK as a two compartmental model with parallel linear and non-linear elimination terms, parallel first-order absorption with a total s.c. bioavailability of 87% in rats. Induction of IGF-1 was described by an indirect response model with stimulation of kin and related to rhGH exposure through an Emax relationship. Increase in bodyweight was directly linked to individual concentrations of IGF-1 by a linear relation. The scaled model provided robust predictions of human systemic PK of rhGH, but exposure following s.c. administration was over predicted. After correction of the human s.c. absorption model, the induction model for IGF-1 well described the human PKPD data.

CONCLUSIONS

A translational mechanistic PKPD model for rhGH was successfully developed from experimental rat data. The model links a clinically relevant biomarker, IGF-1, to a primary clinical end-point, growth/bodyweight gain. Scaling of the model parameters provided robust predictions of the human PKPD in growth hormone-deficient patients including variability.

Factors associated with risk of depression and relevant predictors of screening for depression in clinical practice: a cross-sectional study among HIV-infected individuals in Denmark

OBJECTIVES

Depression and psychiatric disorders are frequent among HIV-infected individuals. The aim of this study was to determine the prevalence of depression and describe the psychiatric history of HIV-infected individuals in an out-patient clinic in Denmark and to identify factors of clinical importance that may be used to identify patients at risk of depression.

METHODS

In 2013, 212 HIV-infected patients were included in a questionnaire study. We used the Beck Depression Inventory II (BDI-II) to assess the prevalence and severity of depressive symptoms. Patients with a BDI-II score ≥ 20 were offered a clinical evaluation by a consultant psychiatrist. Logistic regression was used to determine predictors associated with risk of depression.

RESULTS

Symptoms of depression (BDI-II score ≥ 14) were observed in 75 patients (35%), and symptoms of moderate to major depression (BDI-II score ≥ 20) in 55 patients (26%). There was also a high prevalence of co-occurring mental illness. In a multivariate model, self-reported stress, self-reported perception that HIV infection affects all aspects of life, self-reported poor health, not being satisfied with one's current life situation, previous alcohol abuse, nonadherence to antiretroviral therapy and previously having sought help because of psychological problems were independently associated with risk of depression.

CONCLUSIONS

Symptoms of depression and co-occurring mental illness are under-diagnosed and under-treated among HIV-infected individuals. We recommend that screening of depression should be conducted regularly to provide a full psychiatric profile to decrease the risk of depression and improve adherence and quality of life in this population.

Impact of moderate interval exercise versus supine rest on the pharmacokinetics and pharmacodynamic profiles of subcutaneously administered growth hormone in adult growth hormone deficient patients

BACKGROUND

Diurnal variation in serum growth hormone (s-GH) levels after exogenous GH delivery has previously been reported in patients with no endogenous GH secretion. Changes in postural position or physical activity, leading to changes in blood flow and/or lymphatic drainage may be underlying explanations.

PRIMARY OBJECTIVES

The primary aim of this study is to study a possible impact of exercise and supine rest on pharmacokinetics (PK) and day-to-day variation of subcutaneously (s.c.) administered GH in adult GH deficient (AGHD) patients.

SECONDARY OBJECTIVE

The secondary aim of this study is to compare s-IGF-I, s-insulin, and plasma (p)-glucose profiles after a carbohydrate rich breakfast following s.c. GH injection vs. continuous infusion.

DESIGN AND METHODS

During supine rest eight AGHD males (59.8±8 years, BMI 29.7±4.9 kg/m(2)) were treated with one daily s.c. GH injections of 3 mg/24 h for 48 h (treatment sessions A, B) or a continuous s.c. GH infusion of 3 mg/24 h for 60 h (treatment sessions C, D). Exercise comprised 1 h bicycling with 50 W load on two consecutive days during treatment sessions B and D.

RESULTS

Administration of GH as a bolus injection, but not as a continuous GH infusion, resulted in about 32% higher s-GH levels during exercise (60 min) as well as 30 min after (s-GH logAUC(B-A) difference was 0.28; 95% CI: 0.14-0.4; p<0.001). However, the total s-GH(AUC 0-24 h) (p=0.75) and s-IGF-I(AUC0-48 h) levels (p=0.51) remained unchanged between the two occasions. P-glucose and insulin profiles were significantly higher after carbohydrate rich breakfast before first and second dosing both following s.c. GH injection and continuous infusion (p<0.05).

CONCLUSIONS

Moderate exercise intermittently increased s-GH levels. These changes seem to have no clinical short-term relevance, since total s-GH(24 h) and s-IGF-I(48 h) levels were unaffected.

Circadian variation in the pharmacokinetics of steady state continuous subcutaneous infusion of growth hormone in adult growth hormone deficient patients

BACKGROUND

Previous studies in growth hormone (GH)-deficient (GHD) patients have indicated a possible diurnal variation in the pharmacokinetics (PK) of GH after subcutaneous (sc) GH administration. Thus, higher GH levels were observed during the night with continuous sc infusion, and increased GH bioavailability was reported following daily sc injections in the evening compared to morning.

OBJECTIVE

The aim was to study whether diurnal variability in the PK of sc administered exogenous GH can be reproduced under standard conditions for all study participants, e.g. supine rest.

DESIGN AND METHODS

Eight male GHD patients (59.8 ± 8 years, body mass index 29.7 ± 4.9 kg/m(2)) received a continuous sc infusion of GH (3mg/24h) for 60 h on two different occasions. Diurnal variation in PK of GH was studied during steady state in the last 24h of the infusion period.

RESULTS

Median GH levels were higher at night time (23:00 h-07:00 h) than during the day (10:00 h-18:00 h) for visit 1 [5.1 (4.5-7.2 ng/ml/0.5h) vs. 4.6 (3.7-5.7 ng/ml/0.5h); p<0.05], and reproducible results of diurnal GH variation were obtained during visit 2 [5.7 (4.6-7.4) ng/ml/0.5h vs. 4.6 (3.8-6.0) ng/ml/0.5h, p<0.05]. Reproducible results between days 1 and 2 were also obtained during 08:30 h-20:30 h and 20:30 h-08:30 h, respectively.

CONCLUSIONS

Previous findings of higher nocturnal GH levels were confirmed during steady state continuous sc GH infusion under standard conditions. The underlying mechanisms, e.g. whether GH absorption, distribution or elimination is primarily affected need to be further elucidated.

Pharmacokinetics and pharmacodynamics of different modes of insulin pump delivery. A randomized, controlled study comparing subcutaneous and intravenous administration of insulin aspart

AIMS

To study the pharmacokinetics and pharmacodynamics of three different modes of insulin infusion delivered by means of an insulin pump: subcutaneous bolus insulin injection once an hour, continuous subcutaneous insulin infusion and continuous intravenous insulin infusion.

METHODS

In random order, ten patients with Type 1 diabetes mellitus received insulin aspart with subcutaneous bolus insulin injection, continuous subcutaneous insulin infusion and continuous intravenous insulin infusion. The insulin aspart doses were individualized.

RESULTS

  A non-random, sinus-like variation of serum insulin aspart over time was found with subcutaneous bolus insulin injection compared with continuous subcutaneous insulin infusion and continuous intravenous insulin infusion (P<0.0001). Random variation of serum insulin aspart over time was significantly higher with continuous intravenous insulin infusion compared with subcutaneous bolus insulin injection (P=0.023) and continuous subcutaneous insulin infusion (P=0.013). Mean serum insulin aspart did not differ significantly between subcutaneous bolus insulin injection, continuous subcutaneous insulin infusion and continuous intravenous insulin infusion (P=0.17). Thus, absolute bioavailability was near 100% for both subcutaneous bolus insulin injection and continuous subcutaneous insulin infusion. Statistically significant differences were seen in mean plasma glucose and mean glucose infusion rate, with the highest mean plasma glucose and the lowest mean glucose infusion rate with continuous intravenous insulin infusion, suggesting a slightly lower bioefficacy of continuous intravenous insulin infusion compared with subcutaneous bolus insulin injection and continuous subcutaneous insulin infusion.

CONCLUSIONS

Small but statistically significant differences in pharmacokinetics and pharmacodynamics between subcutaneous bolus insulin injection, continuous subcutaneous insulin infusion and continuous intravenous insulin infusion were observed. However, no major clinically relevant differences were found, suggesting that, for a basal subcutaneous insulin aspart pump therapy, relatively infrequent pump stroke frequency may suffice.

Obesity does not influence the unique pharmacological properties of different biphasic insulin aspart preparations in patients with type 2 diabetes

AIM

To investigate the influence of obesity in type 2 diabetic patients upon pharmacological properties of different biphasic preparations of insulin aspart.

METHODS

A total of 75 type 2 diabetic patients were stratified according to their body mass index (BMI) into 40 non-obese (BMI 23-28 kg/m(2)) and 35 obese (BMI 30-35 kg/m(2)) subjects. The trial was a double-blinded crossover study. In two periods of 4 weeks each the patients received subcutaneous injections of biphasic insulin aspart 50 (BIAsp 50) or biphasic insulin aspart 70 (BIAsp 70) thrice daily in random order. Insulin doses were titrated individually. At the end of each period 24-h serum profiles of insulin aspart, C-peptide and glucose were recorded. The primary endpoint was the area under the curve of serum glucose concentration during 24 h (AUC(Glu)(0-24 h)).

RESULTS

The insulin concentration profiles of BIAsp 50 and 70 were as expected according to the content of protamine-bound insulin aspart (50 and 30% respectively). AUC(Glu(0-24 h)) BIAsp 50/BIAsp 70 ratios were 0.97 (95% CI: 0.90-1.05, p = 0.49) for non-obese and 0.98 (95% CI: 0.92-1.05, p = 0.55) for obese. Fasting serum glucose (FSG) BIAsp 50/BIAsp 70 ratios were 0.90 (95% CI: 0.84-0.96, p = 0.002) for non-obese and 0.90 (95% CI: 0.84-0.97, p = 0.006) for obese. During both treatment regimens the frequency of minor hypoglycaemic episodes was highest for the non-obese group.

CONCLUSIONS

The pharmacokinetic and pharmacodynamic characteristics of the two preparations of biphasic insulin aspart were different; however, they were not influenced by the degree of obesity in type 2 diabetic patients.

Pharmacokinetics following continuous subcutaneous insulin infusion of insulin aspart with or without initial subcutaneous bolus

AIM

To evaluate time to steady state insulin concentration (C(ss)) following continuous subcutaneous insulin infusion (CSII) of insulin aspart (IAsp) with or without an initial s.c. bolus.

METHODS

In random order 10 healthy volunteers were given a basal insulin infusion rate (0.5 U/h) for 8 h with or without an initial s.c. bolus (1.4 U). Serum IAsp was measured until 3 h after infusion was stopped.

RESULTS

An overshoot of IAsp was seen before C(ss) was achieved following an initial bolus of insulin as compared to no bolus. The apparent half-life (t((1/2))) with or without bolus did not differ (p = 0.15). Time to steady state (T(ss)) was evaluated in two ways: (1) T(ss) defined as the first point within an interval of C(ss)+/- 2 x CV was 233 vs. 166 min with and without a bolus respectively (p = 0.068). (2) A t-test was performed for each concentration-time point vs. mean C(ss), and the first point with no significance was defined, T(ss). This gave 208 (p = 0.09) and 178 min (p = 0.24) with and without bolus respectively. Mathematical modelling suggests that an ideal mean bolus should be 0.89 U, and that this bolus dose may result in a shorter T(ss).

CONCLUSION

A bolus of 1.4 U resulted in an overshoot of serum IAsp before C(ss) and a longer period before C(ss) is achieved. Mathematical modelling suggests that a mean bolus of 0.89 U would result in a faster achievement of C(ss) compared to no bolus.

Overnight CSII as supplement to oral antidiabetic drugs in type 2 diabetes

AIM

To evaluate the potential advantages of a constant overnight subcutaneous delivery of insulin in type 2 diabetic patients who fail to achieve glycaemic control on oral antidiabetics.

METHODS

Ten type 2 diabetic patients treated with oral antidiabetic drugs without gaining sufficient glycaemic control were included in this three-period study. All patients received continuous subcutaneous insulin infusion (CSII) with a short-acting insulin analogue, 2 IU/h, for 8 h during three consecutive nights (period A). Based upon the results from period A, two additional dose regimens of three nights (period B and C) were studied in random order. Serum insulin aspart, human insulin and plasma glucose (PG) profiles were recorded.

RESULTS

In period A, fasting plasma glucose (FPG) was reduced from a mean +/- s.d. (mmol/l) value of 11.6 +/- 2.9 to 5.5 +/- 1.6 (p < 0.0001) during the first night. No additional lowering of FPG was seen the two succeeding nights. FPG narrowed as the range before the infusion was 7.3-15.2 mmol/l compared with 3.6-6.1 mmol/l on the last morning after infusion. The variability in PG profile during the first and the last night of CSII was small and not significantly different. The rising insulin aspart was mirrored by a decrease in human insulin. In period B and C, similar tendencies as for period A were seen. In period A, two patients each experienced one mild hypoglycaemic episode.

CONCLUSIONS

CSII with an insulin analogue overnight effectively reduced FPG without occurrence of major hypoglycaemia in type 2 diabetic patients who fail to achieve glycaemic control on oral antidiabetic treatment.

Insulin and glucose profiles during continuous subcutaneous insulin infusion compared with injection of a long-acting insulin in Type 2 diabetes

AIMS

To compare insulin and glucose profiles during basal continuous subcutaneous infusion of a rapid-acting insulin analogue and once daily subcutaneous injection of a long-acting insulin analogue in Type 2 diabetes.

METHODS

Twenty-one patients with Type 2 diabetes treated with oral glucose-lowering agents were randomized in this two-period crossover study to an equivalent 24-h dose of continuous subcutaneous infusion of insulin aspart and subsequently once-daily bedtime subcutaneous injection of insulin glargine, or vice versa, for eight consecutive days. Plasma profiles of insulin and glucose were recorded.

RESULTS

On the last day of each treatment period, the area under the curve (AUC) for glucose was 10% lower on the continuous subcutaneous infusion regimen compared with the insulin injection regimen (P = 0.002). This was accomplished by a flat exogenous insulin infusion profile compared with a peaking profile with injected insulin (AUC was 74% higher after injection compared with pre-injection levels (P = 0.001)). During the last 6 days in each treatment period, the intra-subject variability of exogenous fasting insulin levels in the mornings was 41% lower during insulin infusion compared with insulin injection (P = 0.012). The corresponding intra-subject variability for fasting glucose only showed a tendency to be lower during infusion as compared to the injection regimen (28%; P = 0.104). Thirteen symptomatic-only or minor hypoglycaemic episodes were recorded during the entire infusion period compared with three episodes during the injection period.

CONCLUSIONS

Basal continuous subcutaneous infusion of a rapid-acting insulin analogue improved plasma insulin (more flat insulin profile with a lower variability) and glucose (lower AUC) profiles compared with once-daily subcutaneous injection of a long-acting insulin analogue in Type 2 diabetes.

Long-term effects of continuous subcutaneous infusion versus daily subcutaneous injections of growth hormone (GH) on the insulin-like growth factor system, insulin sensitivity, body composition, and bone and lipoprotein metabolism in GH-deficient adults

It remains uncertain whether close imitation of the physiological pulsatile GH pattern determines the effects of GH treatment in humans. However, human studies have reported comparable metabolic responses to short-term constant and intermittent GH exposure. The aim of the study was to compare the metabolic effects of GH after continuous and intermittent sc delivery. In a parallel design, 14 GH-treated GH-deficient patients (mean age, 37 yr; mean body mass index, 27.4 kg/m(2)) were studied during steady state at the start of the study and after 6 months. Seven patients received daily injections (inj) in the evening as usual, and 7 received a continuous infusion (inf) of GH by means of a portable pump. The GH dose was kept unchanged before and during the study. Serum levels of insulin-like growth factor I (IGF-I) tended to increase in the patients switched to constant infusion (from 175 +/- 36 to 209 +/- 50 microg/L), but the differences obtained during the two regimens [+34.3 (inf) vs. -11.9 (inj)] were not significant (P = 0.34). Serum levels of IGF-II (P = 0.71) and IGF-binding protein (IGFBP)-3 (P = 0.75) were identical during the two modes of treatment. Serum levels of IGFBP-1 (P = 0.72), IGFBP-2 (P = 0.34), and GH-binding protein (P = 0.75) were unaffected by treatment regimen. Serum levels of free fatty acids, reflecting lipolysis, decreased significantly (16%) in the group switched to GH infusion (difference, -99.8 vs. +5 micromol/L; P < 0.03). The GH pattern did not influence insulin sensitivity (P = 0.71) or glucose effectiveness (P = 0.15) derived from Bergman's minimal model. Similarly, the two treatment regimens had no differential impact on lipoprotein levels, bone metabolism, or body composition. In conclusion, continuous and intermittent administrations of GH for 6 months are comparable with respect to the IGF-IGFBP axis, whereas intermittent exposure may be of importance for the lipolytic effect of GH. The data on insulin sensitivity and lipoproteins suggest that constant GH exposure is as safe as intermittent GH administration.

Stimulation of the 150-kilodalton insulin-like growth factor-binding protein-3 ternary complex by continuous and pulsatile patterns of growth hormone (GH) administration in GH-deficient patients

In the circulation insulin-like growth factor I (IGF-I), IGF-binding protein 3 (IGFBP-3), and the acid-labile subunit (ALS) form a 150-kDa ternary complex that is of importance for the regulation of IGF-I bioactivity. GH administration is known to increase each of the single components of the ternary complex, and in GH-deficient rats formation of the 150-kDa complex is induced more by continuous than by pulsatile GH patterns. The aim of the present studies was to study the effects of the GH administration pattern on the formation of the 150-kDa ternary complex in humans. A fixed total GH dose (2 IU/m2-24 h) was administered iv randomly as 1) continuous infusion or 2) eight bolus injections to five GH-deficient patients over a period of 24 h. GH administration significantly increased serum IGF-I and IGFBP-3 levels and the IGF-I/IGFBP-3 ratio. IGF-I levels increased most pronouncedly after continuous administration (P < 0.01). Serum ALS levels increased significantly (both P < 0.005) from 94+/-21 to 180+/-29 (infusion) and from 85+/-17 to 155+/-17 nmol/L (pulses). Employment of neutral size exclusion chromatography enabled separation of IGFBP-3 in ternary complex and noncomplex-bound fractions. IGFBP-3 in the ternary complex increased significantly after GH administration [by 44% (P = 0.048) during infusion and by 62% (P = 0.004) during bolus]. The noncomplex-associated IGFBP-3 fraction, however, did not increase significantly after GH administration (P = NS). Finally, formation of the ternary complex was unaffected by the pattern of GH delivery. In conclusion, short-term GH administration increased all components of the 150-kDa ternary complex. Higher levels of IGF-I after constant GH exposure could indicate an increased bound fraction. However, the GH pattern did not influence the induction of the ternary complex itself. Continuous and intermittent GH patterns may be clinically equally effective during long-term GH therapy, as judged by levels of the components of the ternary complex.

Different effects of continuous and intermittent patterns of growth hormone administration on lipoprotein levels in growth hormone-deficient patients

BACKGROUND

Lipoprotein (a) (Lp(a)) is a risk marker for the development of atherosclerotic coronary heart disease. Growth hormone (GH) administration to GH-deficient (GHD) adults increases serum Lp(a) concentrations, and the levels of Lp(a) and GH are correlated in patients with acromegaly. Studies in rats have demonstrated differential effects of constant and intermittent GH patterns on levels of certain lipoproteins. The aim of the present studies was to describe the impact of intermittent and continuous patterns of GH delivery to GHD patients on serum levels of Lp(a) and other lipoproteins.

METHODS

In one study (A) 10 GHD patients received in random order a fixed GH dose intravenously as: (1) continuous infusion; (2) eight bolus injections, and (3) a combination of 1 and 2. Each study lasted 36 h and was preceded by at least 4 weeks without GH. In another study (B) 13 GHD patients received GH in random order as: (1) continuous subcutaneous (s.c.) infusion, and (2) daily s.c. injections in the evening for 1 month each. The patients were studied during steady-state conditions at the end of each treatment period.

RESULTS

In study A Lp(a) levels increased significantly following continuous (p < 0.05) and combined patterns (p < 0.02) of GH administration to GH-deprived GHD patients, whereas the increase after GH bolus injections alone was not significant (p = 0.14). In study B significantly higher (p < 0.05) serum levels of Lp(a) were obtained after continuous s.c. infusion as compared with daily s.c. injections of GH. Concentrations of the high-density lipoprotein (HDL) cholesterol were significantly lower (p < 0.02) after the continuous GH pattern. Similarly, the HDL fraction Apo A-1 tended to be lower with constant GH delivery (p = 0. 052). Serum levels of total cholesterol, triglyceride and Apo B were similar on the two occasions.

CONCLUSION

Short-term GH administration to GH-deprived GHD patients increased serum Lp(a), but only significantly with continuous delivery. During more prolonged GH exposure, constant s.c. infusion of GH resulted in slightly raised Lp(a) levels and reduced HDL and Apo A1 levels as compared with intermittently administered GH. The findings are consistent with the more effective induction of serum IGF-I levels after continuous patterns of GH delivery previously reported in GHD patients. Longer-term data are needed before conclusions with respect to the impact of the pattern of GH administration on, e.g., the risk of developing coronary heart disease can be drawn.

Circadian variation in serum free and total insulin-like growth factor (IGF)-I and IGF-II in untreated and treated acromegaly and growth hormone deficiency

OBJECTIVE

It is generally accepted that there is no clinically significant circadian variation in total insulin-like growth factor (IGF)-I or total IGF-II in healthy subjects. In contrast there is a significant nocturnal decrease in free IGF-I in healthy subjects, corresponding to the nocturnal increase in IGF binding protein-1. In this study we have investigated the circadian variation in circulating free IGF-I and IGF-II in patients with acromegaly and patients with adult onset growth hormone deficiency.

PATIENTS

Seven acromegalic patients were studied with and without treatment with a slow-release formulation of octreotide. Seven GH-deficient patients were studied without GH replacement. In addition 5 of the GH-deficient patients were studied during GH replacement.

DESIGN

Serum samples were obtained every hour for 24 h. Free IGF-I and IGF-II were measured every 2nd hour. Total IGF-I and IGF-II were measured every 2nd hour (acromegalic patients) or every 4th hour (GH deficient patients). IGF binding protein (IGFBP)-1 was measured every 2nd hour (acromegalic patients) or every hour (GH deficient patients).

RESULTS

In the untreated acromegalic patients there was a significant nocturnal decrease in free IGF-I, but not free IGF-II, before treatment. During treatment there was a significant nocturnal decrease in both free IGF-I and free IGF-II. Peak values of free IGF-I were 112% and 75% above trough (treatment and withdrawal, respectively). In the GH-deficient patients there were no significant circadian variations in free IGF-I or free IGF-II in either of the two occasions. In contrast, there was a significant circadian variation of total IGF-I after adjustment for changes in plasma volume in both treated and untreated acromegaly and GH deficiency in all cases with a peak between 0300 h and 0400 h. The nocturnal increase in total IGF-I ranged from 20% to 35%.

CONCLUSIONS

A significant circadian variation in free IGF-I and IGF-II was demonstrated in acromegalic patients. In contrast no significant circadian variation in free IGF-I and IGF-II was found in GH-deficient patients. Part of the variations may be due to poorly understood variations in IGF-I release. It is not clear whether and to what extent the observed circadian changes in free and total IGF-I are involved in circadian changes in IGF-I bioactivity.

Effects of a 7-day continuous infusion of octreotide on circulating levels of growth factors and binding proteins in growth hormone (GH)-treated GH-deficient patients

In patients with acromegaly, clinical improvement has been reported after octreotide (OCT) treatment, even in cases of only a moderate suppression of growth hormone (GH) levels. In rats, OCT suppresses IGF-I mRNA expression and generation of serum and tissue IGF-I levels. A direct effect of OCT on the IGF system could have therapeutical implications in diabetes mellitus, cardiovascular disease, and certain malignancies in which IGF-I might be involved. The aim of this study was to examine possible GH-independent effects of OCT on IGF components in humans. Six GH-deficient (GHD) patients were studied for 24 h after each of the following treatment regimens (each of 1 weeks duration): (a) daily s.c. GH injection (2 IU/m(2)); (b) as (a) + continuous s.c. infusion of OCT (200 microg/24 h) by means of a portable pump (Nordic Infuser); (c) no treatment. Serum GH binding protein (GHBP) levels tended to be lower after GH and OCT than after GH alone (P =0.10). OCT reduced the GH induced increase in serum IGF-I levels (P<0.05, ANOVA). Mean integrated levels (microg/l) were 359.1+/-49.6 (GH), and 301.6+/-58.9 (GH+OCT). OCT did not significantly reduce serum IGFBP-3 levels (microg/l) [3460+/-270 (GH), and 3112+/-435 (GH+/-OCT);P =0.14]. Serum levels of free IGF-I (P =0.39), IGF-II (P =0.54), and of the acid-labile subunit (ALS) of the ternary complex (P =0.50) were similar during GH+/-OCT as compared with GH alone. After 1 week off GH treatment, significantly lower levels of IGF-I, IGF-II, IGFBP-3, and ALS were recorded (P<0.001). Serum IGFBP-1 levels were significantly higher after GH+OCT than after GH alone (P<0.0001), and levels were even higher without GH. Serum insulin levels (pmol/l) were significantly higher after GH alone as compared with no GH (P<0.05, ANOVA), whereas OCT partly suppressed the insulinotropic effect of GH (P<0. 05) [mean: 114.5+/-33.0 (GH), 91.3+/-29.6 (GH+OCT), 65.9+/-22.5 (no GH)]. This was also reflected in higher blood glucose levels during GH+OCT. Finally, GH+OCT reduced glucagon levels significantly as compared with GH alone (P =0.02). In conclusion, 7 days' administration of OCT to GH-treated GHD patients slightly attenuated serum IGF-I generation, and tended to decrease levels of the other components of the 150 kDa ternary complex. Whether these effects are mediated directly by OCT or indirectly via the accompanying changes in insulin levels remains to be investigated.

Bioavailability and bioactivity of intravenous vs subcutaneous infusion of growth hormone in GH-deficient patients

OBJECTIVE

The bioavailability of GH immunoreactive serum concentrations is reduced following subcutaneous (s.c.) as compared with intravenous (i.v.) administration. Whether this difference also translates into a different biological activity remains to be investigated. The aim of the present study was to evaluate the short-term metabolic effects of GH following i.v. and s.c. delivery.

DESIGN AND MEASUREMENTS

In a cross-over design 10 GH-deficient patients were randomized to receive GH (0.03 microgram (0.1 mU/kg/min) as a continuous i.v. or s.c. infusion for 39 hours on two different occasions. Preceding each study GH therapy was discontinued for 5 days. Serum profiles of GH, IGF-I, IGF-II, IGF binding protein 3 (IGFBP-3), insulin, glucose and non-esterified fatty acids (NEFA) were recorded during the studies. Serum GH was measured by a polyclonal radio-immunoassay (RIA) and by a double monoclonal immunofluorimetric assay (DELFIA).

RESULTS

Higher mean integrated values (AUC) of serum GH (mU/l) were obtained with i.v. GH delivery [47.4 +/- 5.1 (i.v.), 33.3 +/- 3.0 (s.c.), P < 0.05]. The two GH assays showed qualitatively similar results, but higher mean GH concentrations were measured by RIA following both s.c. (P < 0.001) and i.v. infusion (P < 0.001). Serum IGF-I levels displayed different patterns following i.v. and s.c. GH infusion (P < 0.05 by ANOVA) and mean IGF-I levels (micrograms/l) were lower following s.c. GH infusion [159.5 +/- 21.8 (s.c.), 185.2 +/- 27.7 (i.v.), P = 0.002]. Serum IGF-II levels were unaffected by short-term GH treatment and by the route of GH administration. Serum IGFBP-3 levels increased in response to GH administration (P < 0.001), irrespective of route (P = 0.76). The IGF-I/IGFBP-3 molar ratio increased significantly following GH administration (P < 0.001), and a higher ratio was obtained following i.v. infusion (P < 0.005). Subcutaneous GH infusion resulted in significantly lower mean levels of serum NEFA (P < 0.02), whereas similar mean levels of serum insulin (P = 0.54), blood glucose (P = 0.24), energy expenditure (P = 0.13), and respiratory exchange ratio (P = 0.09) were observed on the two occasions.

CONCLUSIONS

A reduced bioavailability of s.c. as compared with i.v. administered GH has been recorded with two independent GH assays, and this was also accompanied by a significant, albeit modest, reduction in biological activity.

Bioavailability and bioactivity of three different doses of nasal growth hormone (GH) administered to GH-deficient patients: comparison with intravenous and subcutaneous administration

The current mode of growth hormone (GH) replacement therapy is daily subcutaneous (s.c.) injections given in the evening. This schedule is unable to mimic the endogenous pulsatile pattern of GH secretion, which might be of importance for the induction of growth and other GH actions. The present study was conducted in order to study the pharmacokinetics of different doses of GH following intranasal (i.n.) administration and the biological activity of GH after i.n. administration as compared with sc and intravenous (i.v.) delivery. Sixteen GH-deficient patients were studied on five different occasions. On three occasions GH was administered intranasally in doses of 0.05, 0.10 and 0.20 IU/kg, using didecanoyl-L-alpha-phosphatidylcholine as an enhancer. On the other two occasions the patients received an sc injection (0.10 IU/kg) and an i.v. injection (0.015 IU/kg) of GH, respectively. The nasal doses and the sc injection were given in random order in a crossover design. In a double-blinded manner the subjects received the three nasal doses as one puff in each nostril. The patients received no GH treatment between the five studies or during the last week before the start of each study. Intravenous administration produced a short-lived serum GH peak value of 128.12 +/- 6.71 micrograms/l. Peak levels were 13.98 +/- 1.63 micrograms/l after s.c. injection and 3.26 +/- 0.38, 7.07 +/- 0.80 and 8.37 +/- 1.31 micrograms/l, respectively, after the three nasal doses. The peak values of the 0.05 and the 0.20 IU/kg nasal doses were significantly different (p = 0.007). The mean levels obtained by the low nasal dose were significantly lower than those obtained with the medium (p < 0.001) and the high dose (p < 0.001), while there was no significant difference between the medium and the high doses. The absolute bioavailability of GH following s.c. relative to i.v. administration was 49.5%. The bioavailabilities of the nasal doses were: 7.8% (0.05 IU). 8.9% (0.10 IU) and 3.8% (0.20 IU). Serum insulin-like growth factor I (IGF-I) levels increased significantly after s.c. administration only. Mean levels were significantly higher after s.c. administration as compared with the i.v. and all three nasal does (p < 0.001). Serum IGF binding protein 3 (IGFBP-3) levels remained unchanged on all five occasions. Mean serum IGFBP-I levels were significantly lower after s.c. GH injection than after administration of the i.v. (p < 0.001) and the three nasal doses (p < 0.005). Subcutaneous GH administration resulted in significantly higher levels of serum insulin and blood glucose (p < 0.001). In conclusion, the bioavailability of nasal GH was low (3.8-8.9%). An i.v. bolus injection of, on average, 1 IU of GH induced no metabolic response. Only s.c. GH administration induced increased levels of IGF-I, insulin and glucose. These data reveal that a closer imitation of the physiological GH pulses than achieved by s.c. GH administration is of limited importance for the induction of a metabolic response to GH.

Body fluids, circadian blood pressure and plasma renin during growth hormone administration: a placebo-controlled study with two growth hormone doses in healthy adults

Side effects that can be related to fluid retention are common during the initial phases of growth hormone (GH) administration. The aim of this study was to examine the changes in body fluid compartments, diurnal blood pressure and plasma renin concentration during GH administration with two different dosages in healthy adults. Eight healthy male subjects aged 24-32 years were examined during three 2-week study periods in a double-blind placebo controlled study. They received, in random order, GH (3 or 6 IU m-2 daily) or placebo during 2 weeks. Bio-impedance was measured every 2nd day, and extracellular volume (ECV) and plasma volume (PV) were isotopically determined at day 6. Blood samples were obtained regularly. Diurnal blood pressure was recorded and 24-h urinary samples were collected at days 0, 6 and 14. ECV (l) was increased by GH (placebo, 19.58 +/- 0.82; 3 IU m-2, 20.77 +/- 1.22; 6 IU m-2, 20.65 +/- 0.94; p<0.01), whereas PV (l) was unaffected (placebo, 3.91+/- 0.20; 3 IU m-2, 4.04 +/- 0.22; 6 IU m-2, 3.90 +/- 0.27). Total body water (l) increased significantly during GH administration (placebo, 50.8 +/- 2.6; 3 IU m-2, 52.6 +/- 2.3; 6 IU m-2, 53.9 +/- 1.8, p<0.05). After 6 days of treatment a significant increase in renin (p = 0.03) was observed. Mean diurnal blood pressure levels remained unchanged, whereas mean diurnal heart rate (min-1) increased significantly (placebo, 75 +/- 3.6; 3 IU m-2, 79 +/- 3.2; 6 IU m-2, 79 +/- 3.7; p<0.01). In conclusion, GH administration induces an elevation in total body water which may involve a stimulation of plasma renin and an increased ECV without any changes in PV or diurnal blood pressure.

Continuous infusion versus daily injections of growth hormone (GH) for 4 weeks in GH-deficient patients

Endogenous GH secretion is pulsatile. Animal studies indicate that GH administered in a pulsatile manner induces growth and insulin-like growth factor I (IGF-I) generation more effectively than continuous administration. Short term human studies, however, have reported similar metabolic effects with constant and pulsatile GH delivery. This study was carried out to compare the metabolic effects of longer term continuous infusion vs. daily injections of GH. Thirteen GH-deficient patients were studied in a cross-over design. The patients were randomized to receive GH as a continuous sc infusion by means of a portable pump for 1 month and as daily sc injections (at 1900 h) for another month. An average daily GH dosage (+/- SEM) of 3.15 +/- 0.27 IU was administered during both periods. Steady state 24-h profiles of GH, IGF-I, IGF-binding proteins (IGFBPs), insulin, glucose, lipid intermediates, and other metabolites were monitored after each treatment period. At the end of each study period (at 0800 h), an oral glucose tolerance test was performed. The mean (+/- SEM) integrated levels of serum GH (micrograms per L) were higher after GH injection [2.51 +/- 0.54 (injection) vs. 1.77 +/- 0.35 (infusion); P < 0.02]. Continuous infusion induced higher nighttime than daytime GH levels (P = 0.01), indicating a diurnal variation in the absorption or clearance of GH. Serum IGF-I levels (micrograms per L) were slightly higher (P < 0.05, by analysis of variance) after continuous GH infusion [312.5 +/- 50.2 (injection) and 334.6 +/- 46.6 (infusion)]. Similarly, constant GH delivery induced higher IGFBP-3 levels (P < 0.05, by analysis of variance). Serum IGFBP-1 levels were similar on the two occasions. Daily GH injections increased daytime insulin levels (P < 0.05), whereas 24-h levels were similar (P = 0.14). The trend toward increased insulin levels after GH injections was also found during the oral glucose tolerance test (P = 0.07). Blood glucose levels were identical on the two occasions. Nocturnal levels of nonesterified fatty acids were higher (P < 0.05) after GH injection. We conclude that continuous sc infusion of GH induced serum IGF-I and IGFBP-3 levels more effectively than daily sc injections. The constant appearance of GH in the circulation did not impair glucose tolerance, but resulted in a less physiological diurnal pattern of nonesterified fatty acids. Our data do not support the concept that a pulsatile GH pattern is of critical physiological significance.

Growth hormone administration stimulates energy expenditure and extrathyroidal conversion of thyroxine to triiodothyronine in a dose-dependent manner and suppresses circadian thyrotrophin levels: studies in GH-deficient adults

OBJECTIVE

The impact of exogenous GH on thyroid function remains controversial although most data add support to a stimulation of peripheral T4 to T3 conversion. For further elucidation we evaluated iodothyronine and circadian TSH levels in GH-deficient patients as part of a GH dose-response study.

PATIENTS

Eight GH-deficient adults, who received stable T4 substitution due to central hypothyroidism; two patients, who were euthyroid without T4 supplementation were studied separately.

DESIGN

All patients were initially studied after at least 4 weeks without GH followed by 3 consecutive 4-week periods in fixed order during which they received daily doses of 1, 2 and 4 IU of GH/m2 body surface area. The patients were hospitalized for 24 hours at the end of each period.

MEASUREMENTS

Circulating total and free concentrations of T4 and T3, total rT3 and TSH were measured once at the end of each study period. Circadian TSH levels were recorded during the period without GH and during GH treatment with 2 IU GH.

RESULTS

Highly significant GH dose-dependent increases in total and free T3 and a reduction in rT3 were observed. The T3/T4 ratio also increased with increasing GH dosages (P < 0.001). In seven patients subnormal T3 levels were recorded in the period off GH, despite T4 levels well within the normal range. Resting energy expenditure also increased and correlated with free T3 levels (r = 0.47, P < 0.05). The circadian TSH levels exhibited a significant nocturnal increase during the period without GH, whereas GH therapy significantly suppressed the TSH levels and blunted the circadian rhythm (mean TSH levels (mU/l) 0.546 +/- 0.246 (no GH) vs 0.066 +/- 0.031 (2 IU GH) (P < 0.05)). The two euthyroid non-T4 substituted patients exhibited qualitatively similar changes in all parameters.

CONCLUSIONS

GH administration stimulated peripheral T4 to T3 conversion in a dose-dependent manner. Serum T3 levels were subnormal despite T4 substitution when the patients were off GH but normalized with GH therapy. Energy expenditure increased with GH and correlated with free T3 levels. GH caused a significant blunting of serum TSH. These findings suggest that GH plays a distinct role in the physiological regulation of thyroid function in general, and of peripheral T4 metabolism in particular.

Metabolic effects of growth hormone administered subcutaneously once or twice daily to growth hormone deficient adults

OBJECTIVE

The aim of this study was to compare the metabolic effects of GH administered subcutaneously either once or twice daily. The actions of GH might depend upon a pulsatile pattern of serum GH. Pulsatile and continuous intravenous delivery of GH, however, induce similar short-term metabolic effects in GH deficient patients. An improved growth response is obtained in GH deficient children when a fixed weekly GH dose is administered by daily subcutaneous injections instead of twice or thrice-weekly intramuscular injections. A more pulsatile pattern and serum GH levels above zero might be achieved by further increasing the injection frequency. Increased daytime GH levels might, however, adversely affect the circadian patterns of metabolic indices, which have been demonstrated to be more successfully reproduced by evening compared with morning GH administration.

DESIGN AND MEASUREMENTS

In a cross-over study, 8 GH deficient patients (age 16-43 years) were treated with 3 IU/m2/24 h of human GH. The dose was injected in the evening for 4 weeks and for another 4 weeks two-thirds was injected in the evening and one-third in the morning. At the end of each period the patients were admitted to the hospital for 37 hours. Steady-state profiles of GH, IGF-I, IGF binding proteins 1 and 3, insulin, glucose, lipid intermediates and metabolites were obtained following administration of 3 IU/m2 of GH (at 1900 h (one injection) and at 1900 and 0800 h (two injections)).

RESULTS

Similar mean integrated levels of serum GH (mU/l) were obtained (7.46 +/- 0.84 (one injection) vs 6.46 +/- 0.62 (two injections) (P = 0.15)). Mean levels +/- SEM of serum IGF-I (micrograms/l) were significantly increased (P < 0.01) following two daily GH injections (330.3 +/- 48.1 (one injection) vs 399.1 +/- 53.0 (two injections)). Serum IGFBP-3 levels were not significantly different on the two occasions, while levels of the GH independent IGFBP-1 (micrograms/l) were slightly but significantly lower following twice-daily GH injections (1.61 +/- 0.42 vs 1.13 +/- 0.56, respectively (P < 0.04)). The pattern of IGFBP-1 was opposite to that of insulin. Similar levels of insulin and glucose were obtained with both GH regimens, while levels of non-esterified fatty acids were significantly higher following once-daily GH injection (P < 0.001).

CONCLUSIONS

Twice-daily GH injections, apart from producing a more physiological serum GH profile, were superior to one injection in increasing serum IGF-I and decreasing IGFBP-1 levels. Both of these changes tend to amplify the effects of the administered GH. Twice-daily injections, however, resulted in lower night-time levels of lipid intermediates.

Nasal absorption of growth hormone in normal subjects: studies with four different formulations

OBJECTIVE

Current growth hormone (GH) therapy with daily subcutaneous injections results in elevated serum concentrations of GH lasting for several hours, whereas physiologic GH secretion is characterized by a short-duration peak and low basal concentrations. A closer imitation of this pattern might be achieved by administering GH nasally. We studied the effect on the absorption of nasally administered human GH of increasing concentrations of the enhancer didecanoyl-L-alpha-phosphatidylcholine (DDPC).

DESIGN

Four formulations of nasal GH containing the enhancer DDPC in the relative concentrations 0, 4, 8, and 16% w/w were administered in random order.

SETTING

Participants were admitted to the hospital during the four study periods.

INTERVENTIONS

On four occasions the subjects received GH 6 IU (2 mg) in each nostril. Blood was sampled frequently for four hours. Anterior rhinoscopy was performed at 0 and 4 h. During the study the subjects completed a questionnaire to record nasal symptoms.

PATIENTS

Sixteen healthy subjects were examined at 0800 h after an overnight fast.

MAIN OUTCOME MEASURES

Bioavailability of a nasal preparation of human GH: area under the curve (AUC), the maximum concentration (Cmax), and the time to reach maximum concentration (tmax). Scores for each nasal symptom were recorded as were the total scores.

RESULTS

AUC, Cmax, and tmax were not significantly affected by increasing the DDPC concentration from 0 to 4 percent or from 8 to 16 percent. AUC and Cmax, however, increased significantly when the concentration of DDPC was changed from 4 to 8 percent. Mean (+/- SD) AUC (microgram.h/L) increased from 20.51 +/- 10.53 (4 percent) to 46.14 +/- 34.59 (8 percent), (p < 0.005). Mean (+/- SD) of Cmax (microgram/L) increased from 11.11 +/- 5.02 (4 percent) to 28.22 +/- 20.85 (8 percent), (p = 0.002). Mean (+/- SD) of tmax (min) was not significantly different on the four occasions (range 40.6 +/- 36.4 to 61.0 +/- 45.2 min, p = 0.13). The symptom scores (range 17.56-21.5, maximum 360) were not significantly different (p = 0.59).

CONCLUSIONS

Increasing the relative concentration of the enhancer DDPC increases the absorption of nasally administered GH.

Pharmacokinetics and metabolic effects of growth hormone injected subcutaneously in growth hormone deficient patients: thigh versus abdomen

OBJECTIVE

The absorption of insulin following subcutaneous (s.c.) injection is faster in the abdomen than the thigh. We therefore studied the effect of changing the site of injection on the absorption and metabolic effects of human growth hormone.

DESIGN AND MEASUREMENTS

In a cross-over study human GH (Norditropin) was injected s.c. in the thigh or abdomen in random order. Ultrasonography of the thigh and abdomen was performed in order to evaluate the thickness of the s.c. tissue. After each treatment period (4 weeks), serum profiles of GH, IGF-I, IGF binding proteins 1 and 3 (IGFBP-1 and IGFBP-3), glucose, insulin, non-esterified fatty acids (NEFA), glycerol, 3-hydroxybutyrate, alanine, lactate and glucagon were measured for 37 hours after GH injection (3 IU/m2 at 1900 hour).

PATIENTS

Nine GH deficient patients (five males, four females).

RESULTS

The mean (+/- SEM) thickness of the s.c. tissue (mm) was higher on the abdominal site (9.35 +/- 1.38 (thigh), and 22.61 +/- 2.19 (abdomen), P < 0.001). Mean (+/- SEM) integrated levels (area under the curves (AUC) divided by time) of GH (mU/l) were identical: 5.54 +/- 0.70 (thigh) versus 5.48 +/- 0.64 (abdomen) (P = 0.91). AUC (mU/l) for the initial 6 hours were, however, significantly different (14.10 +/- 3.76 (thigh) and 19.02 +/- 3.18 (abdomen), P = 0.02). Maximal serum concentration (Cmax) (mU/l) 23.18 +/- 3.86 (thigh) and 29.66 +/- 4.78 (abdomen) (P = 0.19) was achieved faster (Tmax) following injection in the abdomen. Tmax (hours) was 5.89 +/- 0.41 (thigh) and 4.26 +/- 0.49 (abdomen) (P < 0.002). Mean IGF-I levels (microgram/l) were unaffected by GH injection sites (355 +/- 60 (thigh) and 365 +/- 63 (abdomen), P = 0.61). Mean IGFBP-3 levels (microgram/l) were significantly different (2100 +/- 143 (thigh), and 2350 +/- 176 (abdomen), P = 0.05). Mean levels of IGFBP-1, insulin, glucose, lipid intermediates, metabolites and glucagon were not significantly different.

CONCLUSIONS

Human GH was absorbed faster when injected s.c. in the abdomen as compared with the thigh, despite the thicker s.c. tissue on the abdomen. Apart from higher IGFBP-3 levels after s.c. injections in the abdomen, similar metabolic effects of GH were obtained with the two injection sites.

Absorption kinetics of two highly concentrated preparations of growth hormone: 12 IU/ml compared to 56 IU/ml

The purpose of this study was to compare the relative bioavailability of two highly concentrated (12 IU/ml versus 56 IU/ml) formulations of biosynthetic human growth hormone administered subcutaneously. After pretreatment with growth hormone for at least four weeks, nine growth hormone deficient patients with a mean age of 26.2 years (range 17-43) were studied two times in a randomized design, the two studies being separated by at least one week. At the start of each study period (7 p.m.), growth hormone was injected subcutaneously in a dosage of 3 IU/m2. The 12 IU/ml preparation of growth hormone was administered on one occasion, and the 56 IU/ml preparation on the other. Serum profiles of growth hormone were monitored by frequent measurements for 24 hr. Bioavailability and absorption dynamics were evaluated by the absorption fraction, F56 IU/12 IU, calculated from the mean integrated levels (AUC) of growth hormone, and the observed time, Tmax, to reach maximum concentration, Cmax. Levels of serum IGF-I, IGFBP-3, insulin and blood glucose were measured to study the short term metabolic effects of growth hormone. The absorption fraction, F (S.D.) was 1.034 (0.163). The 90% confidence interval was 0.934-1.144, which is included in the interval 0.8-1.25, implying that the two preparations are bioequivalent. Neither AUC (P = 0.90), Cmax (p = 0.47) or Tmax (P = 0.86) for the two formulations of growth hormone were significantly different. Similar levels of serum IGF-I, IGFBP-3, insulin and blood glucose were obtained.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of octreotide on insulin-like growth factor I and metabolic indices in growth hormone-treated growth hormone-deficient patients

Animals studies have demonstrated that in addition to inhibiting growth hormone (GH) secretion octreotide inhibits in a direct manner hepatic or peripheral insulin-like growth factor I (IGF-I) generation. To test this hypothesis in humans we studied ten GH-deficient patients with frequent blood sampling during 38 h on two occasions. Regular GH therapy was discontinued 72 h prior to each study period. At the start of each study a subcutaneous (sc) injection of GH (3 IU/m2) was given (at 18.00 h). In a single-blinded crossover design, patients received a continuous sc infusion of either octreotide (200 micrograms/24 h) or placebo (saline). The pharmacokinetics of GH were similar on the two occasions. The area under the curve +/- SEM of serum GH was 142.5 +/- 53.6 micrograms.l-1 x h-1 (octreotide) and 144.8 +/- 41.8 micrograms.l-1 x h-1 (placebo), (p = 0.73); Cmax (microgram/l) was 12.5 +/- 1.47 (octreotide) and 12.8 +/- 1.42 (placebo) (p = 0.83), and Tmax (h) was 6.1 +/- 0.97 (octreotide) and 5.2 +/- 0.65 (placebo) (p = 0.49). Growth hormone administration was associated with an increase in serum IGF-I (microgram/l), which was identical during the two studies, from 85.3 +/- 19.4 to 174.25 +/- 30.3 for octreotide and from 97.0 +/- 26.4 to 158.8 +/- 28.2 for placebo. Mean IGF-I levels (microgram/l) were 138.2 +/- 25.1 (octreotide) and 134.5 +/- 28.6 (placebo) (p = 0.78). Similarly, the increase in IGF binding protein 3 (IGFBP-3) levels was identical. Mean IGFBP-3 levels (microgram/l) were 2303 +/- 323 (octreotide) and 2200 +/- 361 (placebo) (p = 0.25).(ABSTRACT TRUNCATED AT 250 WORDS)

Subcutaneous absorption kinetics of two highly concentrated preparations of recombinant human growth hormone

OBJECTIVE

The relative bioavailability of two highly concentrated (12 IU/ml) formulations of biosynthetic human growth hormone (GH) administered subcutaneously was compared.

DESIGN

A randomized, crossover study. Conventional GH therapy was withdrawn 72 hours before each study period. There was a washout period of at least four weeks between the study periods.

SETTING

Participants were recruited from an outpatient clinic and were hospitalized during the two study periods.

PATIENTS

Fourteen GH-deficient patients (mean age 25.2 y, range 14-54). One patient was excluded from data analysis because of signs of endogenous GH secretion.

INTERVENTIONS

At the start of each study period, GH 3 IU/m2 was injected subcutaneously. The two formulations, PenFill and PenSet, differ in the buffers used and in the relative content of mannitol and glycine. Serum profiles of GH were monitored frequently for 24 hours. Samples were taken every 30 minutes for 6 hours and then hourly.

MAIN OUTCOME MEASURES

Bioavailability (F) and absorption dynamics of human GH were measured. The relative absorption fractions estimated from the areas under the individual serum concentration curves from 0 to 24 hours, and the observed time (Tmax) to reach the maximum concentration (Cmax) were determined. Short-term metabolic effects of GH on insulin-like growth factor (IGF-I), glucose, and insulin were determined.

RESULTS

The geometric mean (SD) of F was 0.910 (1,236). The 90 percent confidence interval was 0.819-1.010. Mean (+/- SD) of Cmax was 12.65 +/- 5.89 and 12.58 +/- 4.40 ng/mL for PenFill and PenSet, respectively. Corresponding values for Tmax were 5.49 +/- 1.55 and 5.89 +/- 1.79 hours for PenFill and PenSet, respectively. There was a considerable interindividual variation, but the relative absorption fraction did not significantly differ from 1 (p = 0.13). Neither Cmax (p = 0.74) nor Tmax (p = 0.58) of the two formulations was significantly different. Injection of the two formulations induced similar increments in serum IFG-I (p = 0.48). Serum insulin and blood glucose concentrations were not significantly different.

CONCLUSIONS

There is no significant difference between the absorption kinetics and short-term metabolic effects of these two highly concentrated formulations of biosynthetic GH. The two formulations are bioequivalent.

Investigations of the excretion of gamma-glutamyl-transpeptidase into the urine

The excretion of the enzyme gamma-glutamyl-transpeptidase and its isoenzymes into the urine was investigated in patients with renal diseases and compared with the excretion of the enzymes leucine-aminopeptidase and lactate-dehydrogenase. In animal experiments an increased excretion of these enzymes was found after autotransplantation. Increased excretion of gamma-glutamyl-transpeptidase was also found in patients with glomerulonephritis and in the polyuric phase of acute tubular necrosis, but not in cases of pyelonephritis and in the oliguric phase of acute tubular necrosis. The alterations of the isoenzyme pattern during diseases with increased enzyme excretion are in accordance with the hypothesis that the enzymes are liberated from the kidney tissue into the urine, and only a minority stems from the blood. Investigation of the excretion of gamma-glutamyl-transpeptidase and its isoenzymes into the urine seems to be of both scientific and clinical interest.