Serum golimumab concentration and anti-drug antibodies are associated with treatment response and drug survival in patients with inflammatory joint diseases: data from the NOR-DMARD study.

Objectives: This study aimed to identify the therapeutic target concentration and frequency of anti-drug antibodies (ADAbs) in golimumab-treated patients with inflammatory joint disease (IJD).Method: Associations between golimumab concentration, ADAbs, and treatment response were examined in 91 patients with IJD [41 axial spondyloarthritis (axSpA), 20 rheumatoid arthritis (RA), and 30 psoriatic arthritis (PsA)] included in the NOR-DMARD study. Treatment response was defined by Ankylosing Spondylitis Disease Activity Score (ASDAS) clinically important improvement in axSpA, European League Against Rheumatism (EULAR) good/moderate response in RA, and improvement of ≥ 50% in modified Disease Activity index for PSoriatic Arthritis (DAPSA) (28 swollen/tender joint counts) in PsA. Serum drug concentrations and ADAbs were analysed using automated in-house assays.Results: At inclusion, 42% were biological disease-modifying anti-rheumatic drug naïve and 42% used concomitant synthetic disease-modifying anti-rheumatic drug. The median golimumab concentration was 2.2 (interquartile range 1.0-3.5) mg/L. The proportions of responders after 3 months among patients with golimumab concentration < 1.0, 1.0-3.9, and ≥ 4.0 mg/L were 19%, 49%, and 74%, respectively. A higher rate of treatment discontinuation was seen in patients with serum golimumab concentration < 1.0 compared to ≥ 1.0 mg/L (hazard ratio 3.3, 95% confidence interval 1.8-6.0, p < 0.05). ADAbs were detected in 6%, and were associated with lower drug concentrations and both reduced treatment response and drug survival.Conclusions: Golimumab concentrations ≥ 1.0 mg/L were associated with improved treatment response and better drug survival, although some patients may benefit from higher concentrations. This study suggests a rationale for dosing guided by therapeutic drug monitoring in golimumab-treated patients with IJD. The results should be confirmed in larger studies including trough samples, and the efficacy of such a strategy must be examined in randomized controlled trials.

Chronic fatigue in 812 testicular cancer survivors during long-term follow-up: increasing prevalence and risk factors.

BACKGROUND: Chronic fatigue (CF) has been reported to be slightly more prevalent in testicular cancer survivors (TCSs) than in the general population. In this study, we wished to explore possible determinants of CF in TCSs median 12 (survey I) and 19 years (survey II) after treatment, in particular the relation to late effects after treatment. PATIENTS AND METHODS: Overall, 812 TCSs treated between 1980 and 1994 provided blood samples (testosterone and luteinizing hormone) and completed questionnaires at survey I (1998-2002) and survey II (2007-2008). Hormone levels were categorized according to quartile thresholds for decadal age groups of controls. Associations between CF and possible risk factors, including the Hospital Anxiety and Depression Scale (HADS), treatment, physical activity, hormone levels, neurotoxicity, and comorbidity, were analyzed by logistic regression. RESULTS: Prevalence of CF increased from 15% at survey I to 27% at survey II (P < 0.001). At survey II, risk for CF was increased three- to four-fold for high levels of neuropathy compared with no neuropathy, and two- to three-fold for high levels of Raynaud-like phenomena, and having testosterone levels in the lowest quartile, while being moderately and highly physically active, had a protective effect. Risk for CF in TCSs with higher levels of HADS-Anxiety and HADS-Depression was increased two- to five-fold, respectively. CONCLUSIONS: The increasing prevalence of CF in TCSs is a novel finding. Lifestyle interventions, early detection and treatment of depression and anxiety, and possibly testosterone substitution might reduce the risk of CF. Extended long-term follow-up seems to be important.

Associations between patient-reported late effects and systemic cytokines in long-term survivors of head and neck cancer treated with radiotherapy.

PURPOSE: Head and neck cancer (HNC) treatment may lead to late effects and impaired health-related quality of life of survivors. Knowledge on long-term late effects after radiotherapy (RT) and potential underlying biological mechanisms is lacking. We assessed the prevalence of xerostomia, dysphagia, and chronic fatigue (CF) in HNC survivors ≥ 5 years post-RT, and examined associations between pro-inflammatory cytokines and late effects. METHODS: In a cross-sectional study, 263 HNC survivors treated between 2007 and 2013 were enrolled. They completed validated questionnaires assessing xerostomia and dysphagia (the EORTC QLQ-H&N35), and CF (the Fatigue Questionnaire), and underwent blood sampling and clinical examination. Pro-inflammatory cytokines were analyzed in 262 survivors and 100 healthy age- and gender-matched controls. RESULTS: Median time since treatment was 8.5 years. The proportions of survivors reporting xerostomia, dysphagia, and CF were 58%, 31%, and 33%, respectively, with a preponderance of females. We found no significant associations between IL-6, IL-8, IP-10, TARC, TNF, or ENA-78 and the three late effects. The odds of having elevated levels of IL-6 and IP-10 were significantly higher in the survivors compared to the controls. CONCLUSIONS: More than one-third of long-term HNC survivors experienced xerostomia, dysphagia, and CF. Persistent inflammation, with elevated systemic cytokines, was not associated with these late effects, although HNC survivors had higher levels of some cytokines than the controls. IMPLICATIONS FOR CANCER SURVIVORS: This study provides new knowledge on late effects that can serve as grounds for informing patients with HNC about risk of late effects more than 5 years after RT.

Sperm counts and endocrinological markers of spermatogenesis in long-term survivors of testicular cancer.

BACKGROUND: The objective of this study was to assess markers of spermatogenesis in long-term survivors of testicular cancer (TC) according to treatment, and to explore correlations between the markers and associations with achieved paternity following TC treatment. METHODS: In 1191 TC survivors diagnosed between 1980 and 1994, serum-follicle stimulating hormone (s-FSH; n=1191), s-inhibin B (n=441), and sperm counts (millions per ml; n=342) were analysed in a national follow-up study in 1998-2002. Paternity was assessed by a questionnaire. RESULTS: At median 11 years follow-up, 44% had oligo- (<15 millions per ml; 29%) or azoospermia (15%). Sperm counts and s-inhibin B were significantly lower and s-FSH was higher after chemotherapy, but not after radiotherapy (RT), when compared with surgery only. All measures were significantly more abnormal following high doses of chemotherapy (cisplatin (Cis)>850 mg, absolute cumulative dose) compared with lower doses (Cis ≤ 850 mg). Sperm counts were moderately correlated with s-FSH (-0.500), s-inhibin B (0.455), and s-inhibin B : FSH ratio (-0.524; all P<0.001). All markers differed significantly between those who had achieved post-treatment fatherhood and those with unsuccessful attempts. CONCLUSION: The RT had no long-term effects on the assessed markers of spermatogenesis, whereas chemotherapy had. At present, the routine evaluation of s-inhibin B adds little in the initial fertility evaluation of TC survivors.

The mild inflammatory response in febrile neutropenic lymphoma patients with low risk of complications is more pronounced in patients receiving tobramycin once daily compared with three times daily.

We evaluated inflammatory markers in febrile neutropenic lymphoma patients undergoing high-dose chemotherapy with autologous stem cell support. Based on MASCC scores, our patients had a low risk of serious complications and a perspective of a benign initial clinical course of the febrile neutropenia. We also studied the impact of tobramycin given once versus three times daily on these immune markers. Sixty-one patients participating in a Norwegian multicentre prospective randomized clinical trial, comparing tobramycin once daily versus three times daily, given with penicillin G to febrile neutropenic patients, constituted a clinically homogenous group. Four patients had bacteraemia, all isolates being Gram-positive. Thirty-two patients received tobramycin once daily, and 29 patients received tobramycin three times daily. Blood samples were taken at the onset of febrile neutropenia and 1-2 days later. All samples were frozen at -70 °C and analysed at the end of the clinical trial for C-reactive protein (CRP), procalcitonin (PCT), complement activation products, mannose-binding lectin (MBL) and 17 cytokines. We found a mild proinflammatory response in this series of patients. CRP was non-specifically elevated. Ten patients with decreased MBL levels showed the same mild clinical and proinflammatory response. Patients receiving tobramycin once daily showed a more pronounced proinflammatory response compared with patients receiving tobramycin three times daily. Overall, febrile neutropenic cancer patients with a benign clinical course show a mild proinflammatory immune response.

Gonadal function in male patients after treatment for malignant lymphomas, with emphasis on chemotherapy.

Gonadal function was assessed in male lymphoma survivors based on serum hormone levels (LH, FSH, testosterone, SHBG), and was related to treatment, age and observation time. Male patients

The usefulness of detecting thyroglobulin in fine-needle aspirates from patients with neck lesions using a sensitive thyroglobulin assay.

The aim of this study was to assess the diagnostic utility of thyroglobulin (Tg) in fine needle aspirates (Tg-FNAB) of nonthyroidal neck masses using a sensitive in-house method for detecting Tg in washout specimens. A total of 256 samples from 145 patients were evaluated for Tg in washout specimen from FNAB and compared to corresponding cytological smear and histology of 46 surgical specimens. Tg was measured by a sensitive in-house time-resolved immunofluorometric assay. The sensitivity for Tg-FNAB alone or in combination with cytological findings was found to be 100% in both the follow-up group and before primary surgery. In the follow-up group the specificity of Tg-FNAB was 100%. Fifty-nine of 60 follow-up specimens with malignant cytology were Tg-FNAB positive (n = 195). Histological examination of one lymph node with malignant cytology and negative Tg-FNAB showed metastasis from carcinoma of the salivary gland. Tg-FNAB was positive in 25 specimens with suspicious or cystic cytology. Tg-FNAB values were high (median 4557 microg/l, range 122-37200 microg/l) in washout specimen from cystic metastasis from which cytology did not confirm malignancy. Of the 20 lymph nodes with histology confirming metastasis from differentiated thyroid carcinoma (DTC), the Tg-FNAB was positive in 19 and intermediate in one. However, before primary surgery, two Tg-FNABs were false positive compared to the histology of the lymph nodes. TgAb in serum did not interfere with FNAB-Tg measurements. Tg-FNAB measurement is accurate with high sensitivity (100%) and of great importance in detecting cystic metastasis when cytology is not conclusive. Even metastases to small neck lymph nodes may be detected by using sensitive Tg-assay. Serum thyroglobulin antibodies appear to have ignorable effect on the clinical performance of Tg-FNAB.

1,25-Dihydroxyvitamin D3 attenuates adenylyl cyclase activity in rat thyroid cells: reduction of thyrotropin receptor number and increase in guanine nucleotide-binding protein Gi-2 alpha.

1,25-Dihydroxyvitamin D3 [1,25-(OH)2D3] is the most potent of the naturally occurring vitamin D metabolites. In rat thyroid FRTL-5 cells, 1,25-(OH)2D3 attenuated the increase in TSH-stimulated adenylyl cyclase activity obtained by removing TSH from the culture medium. When cells were incubated with 1,25-(OH)2D3 (10 nmol/liter; 4 days), the binding capacity for specific [125I]TSH binding decreased from 20.1 +/- 1.8 to 8.8 +/- 1.6 fmol/10(6) cells (mean +/- SEM; n = 4; P < 0.01) compared to that in control cells. The Kd did not change (mean +/- SEM, 0.46 +/- 0.09 vs. 0.25 +/- 0.07 nmol/liter; n = 4; P = NS). Western blotting revealed no change in the membrane content of the adenylyl cyclase (AC) stimulatory guanine nucleotide-binding protein (G-protein) alpha-subunit (Gs alpha) during 1,25-(OH)2D3 treatment. Similarly, levels of the AC inhibitory G-protein Gi-3 alpha- and G-protein beta-subunits were not altered by 1,25-(OH)2D3. However, Western blotting with antibodies recognizing both Gi-1 alpha and Gi-2 alpha was augmented 4-fold, presumably representing an increase in Gi-2 alpha only, as Gi-1 alpha messenger RNA (mRNA) was not detected in FRTL-5 cells. 1,25-(OH)2D3 (10 nmol/liter; 4 days) reduced cholera toxin (10 nmol/liter)-stimulated AC activity to 85% of the control value (P < 0.05), whereas forskolin (100 mumol/liter)-stimulated direct activation of AC was inhibited by 39%. The TSH receptor mRNA level correlated to the beta-actin mRNA was 2-fold higher in control cells compared to that in 1,25-(OH)2D3-treated cells 12 h after TSH removal. Only minor alterations in the Gs alpha mRNA/beta-actin mRNA and Gi-3 alpha mRNA/beta-actin mRNA ratios were observed during 1,25-(OH)2D3 treatment, whereas Gi-2 alpha mRNA increased 3-fold compared to that in control cells. No change in the resting intracellular Ca2+ concentration could be detected after 4 days of 1,25-(OH)2D3 treatment. Our studies show that 1,25-(OH)2D3 attenuates AC activity by reducing the TSH receptor number and increasing the level of the AC inhibitory G-protein Gi-2 alpha in FRTL-5 cells.

Perfusion system for studying peptide secretion from endocrine cells with high time resolution.

To study the secretion from endocrine cells in culture, we have developed a cell column perfusion system with a time resolution of 4 s. The core of the system is a perfusion chamber with a cell-supporting matrix of monosized polystyrene beads. The particles are solid and can withstand a high pressure gradient without deformation. The minimum amount of cell material required to obtain detectable levels of secretory products is a function of the assay sensitivity, perfusion flow, fraction volume and time resolution. The volume of the perfusion chamber is therefore adjustable to satisfy varying demands of minimum cell number. The general flow characteristics of the system were characterized using radiolabeled substances of various molecular sizes. Using the system in secretory studies of rat pituitary tumor (GH4C1) cells, we have identified differences in secretion profiles that may be related to the kinetics of the different transmembrane and intracellular mechanisms involved.

Phorbol esters and thyroliberin have distinct actions regarding stimulation of prolactin secretion and activation of adenylate cyclase in rat pituitary tumour cells (GH4C1 cells).

The phorbol ester 12-O-tetradecanoyl phorbol 13-acetate (TPA) enhances the effects of TRH on phase II of prolactin secretion as well as on hormone synthesis at both low and high TPA receptor occupancy. Furthermore TPA, but not the biologically inactive substance 4 alpha-phorbol 12,13-didecanoate (4 alpha-PDD), stimulates the particulate bound adenylate cyclase with a time course paralleling that of TRH activation. However, the combined additions of TRH and TPA activate this cyclase in an additive manner while the Gpp(NH)p- and the forskolin-sensitive enzyme are unaffected by TPA addition. Polymyxin B, which inhibits protein kinase C, abolishes activation of adenylate cyclase by TPA without interfering with the stimulatory action of TRH. Also, when phosphatase activity is preferentially inhibited by pretreatment of the cells with sodium vanadate, the TRH-sensitive cyclase is unaltered, while TPA activation is obliterated. Maximal stimulation of adenylate cyclase by cholera toxin pretreatment, obliterated the actions of TRH and TPA. Cells pretreated with pertussis toxin retained their TRH-sensitive cyclase, however, TPA-responsiveness was lost. We therefore suggest that the action of TPA as it relates to activation of adenylate cyclase, is probably mediated via the Gi component of the adenylate cyclase complex, while TRH stimulates the enzyme via the classical pathway involving the stimulatory GTP binding protein (Gs).

Thyrotropin-releasing hormone-stimulated inositol trisphosphate formation is liable to thyrotropin-releasing hormone-induced desensitization by a calcium-dependent mechanism.

In cultured rat pituitary cells (GH4C1 cells) the ability of thyrotropin-releasing hormone (TRH) to stimulate phosphodiesteratic cleavage of phosphatidylinositol 4,5-bisphosphate (PIP2) by a phospholipase C-type reaction was confirmed. The dose-response relationship for the TRH-stimulated phospholipase C was elucidated as was the relationship between the various inositol phosphates formed during the first few seconds after stimulation. The TRH-stimulated phospholipase C was subject to desensitization by repeated TRH treatment of cell cultures. This desensitization was dependent on the dose of TRH during preincubation. Following desensitization no decline in the levels of PIP2 was detected, even in the presence of decreased levels of PIP2 precursors. The TRH-stimulated phospholipase C activity was not attenuated following pretreatment with 12-O-tetradecanoylphorbol 3-acetate (TPA) to stimulate protein kinase C activity, and TRH also induced desensitization in the presence of the protein kinase C inhibitor polymyxin B. Thus, regulation of protein kinase C activity seemed not to be involved in the desensitization process. It is suggested that the ability of TRH to desensitize its own receptors and their link to phospholipase C, is mediated by the rise in intracellular calcium that is initiated by the TRH-receptor interaction.

Vasoactive intestinal peptide causes a calcium-dependent stimulation of prolactin secretion in GH4C1 cells.

We have studied the effects of vasoactive intestinal peptide (VIP) on PRL secretion in a Bio-Gel column parafusion system containing rat pituitary tumour cells (GH4C1). A dose-dependent increase in PRL release was observed with half-maximal and maximal effect (2.1-fold) at 8 X 10(-8) and 5 X 10(-6) M, respectively. The PRL-stimulatory effect of VIP was instantaneous and maintained during the parafusion experiments (up to 60 min). On a molar basis VIP was always less effective than thyroliberin (THR), and the maximum stimulation of PRL release obtained with TRH was 1.2-3.0-fold higher (n = 12) than the maximum effect seen after VIP administration. The PRL-releasing effects of VIP, THR and high extracellular K+ were almost completely abolished in the presence of two inhibitors of voltage-sensitive Ca2+ channels, CoCl2 (10(-3) M) and verapamil (10(-4) M). In Ca2+-free buffer VIP, TRH and high extracellular K+ had only negligible effects, but the responses were fully restored in the presence of normal concentrations of extracellular Ca2+. In contrast to TRH, VIP had no demonstrable effect on the Ca2+-dependent action potentials of the GH4 cells.

Calcitriol attenuates the basal and vasoactive intestinal peptide-stimulated cAMP production in prolactin-secreting rat pituitary (GH4C1) cells.

A clonal strain of prolactin-producing rat pituitary tumour cells (GH4C1 cells) was used to study the effect of calcitriol on cyclic adenosine monophosphate (cAMP) production. Calcitriol (10 nM) attenuated both the basal and vasoactive intestinal peptide (VIP)-stimulated cAMP production after 2 days' pretreatment of the cells. The effect was detectable at 1 nM and maximal at about 10 nM. Calcitriol was at least 100 times more potent than calcidiol and 24-hydroxycalcidiol. Calcitriol (10 nM, 4 days) did not affect the specific binding of 125I-VIP, but attenuated the guanosine 5'-O-(3-thiotriphosphate) (GTPgammaS)-stimulated (100 microM) adenylyl cyclase activity by 25%. Calcitriol (10 nM, 4 days) also attenuated both the Mn2+ (1 mM) and the forskolin-stimulated (10 microM) adenylyl cyclase activity by 43 and 41%, respectively. In conclusion, these data suggest that calcitriol attenuates the basal and VIP-stimulated cAMP production by inhibiting the catalytic subunit of the adenylyl cyclase as well as the amount of the G protein Gs alpha.

Vasoactive intestinal peptide and peptide with N-terminal histidine and C-terminal isoleucine increase prolactin secretion in cultured rat pituitary cells (GH4C1) via a cAMP-dependent mechanism which involves transient elevation of intracellular Ca2+.

Vasoactive intestinal peptide (VIP) and peptide (P) with N-terminal histidine and C-terminal isoleucine (PHI) stimulated prolactin (PRL) secretion from GH4C1 cells equipotent with ED50 values of 30-50 nM. In a parafusion system optimized to give high time resolution both VIP and PHI increased PRL secretion with a delay of about 60 s and subsequent to the activation of the adenylate cyclase. Thyroliberin (TRH) increased PRL secretion within 4 s. The dose-response curves for VIP- and PHI-stimulated cAMP accumulation were superimposable on those for PRL secretion. At submaximal concentrations the effects of VIP and PHI on both cAMP accumulation and PRL secretion were additive, whereas the effects were not additive at concentrations giving maximal effects. VIP and PHI increased [Ca2+]i measured by quin-2 in a different way than TRH, without inducing changes in the electrophysiological membrane properties of the GH4C1 cells. We conclude that both VIP and PHI stimulate PRL secretion via a cAMP-dependent process involving an increase in [Ca2+]i.

Prevalence of thyroid disease, thyroid dysfunction and thyroid peroxidase antibodies in a large, unselected population. The Health Study of Nord-Trondelag (HUNT).

OBJECTIVE: To examine the prevalence of thyroid disease and dysfunction including thyroid autoimmunity in Norway. MATERIALS AND METHODS: All inhabitants 20 years and older (94009) in Nord-Trondelag were invited to participate in a health survey with a questionnaire and blood samples. RESULTS: The prevalence of former diagnosed hyperthyroidism was 2.5% in females and 0.6% in males, hypothyroidism 4.8% and 0.9%, and goitre 2.9% and 0.4% respectively. In both sexes the prevalence increased with age. In individuals without a history of thyroid disease the median, 2.5 and 97.5 percentiles for TSH (mU/l) were 1.80 and 0.49-5.70 for females and 1. 50 and 0.56-4.60 for males. The TSH values increased with age. When excluding individuals with positive thyroid peroxidase antibodies (TPOAb) (>200U/ml), the 97.5 percentiles dropped to 3.60 mU/l and 3. 40 mU/l respectively. The prevalence of pathological TSH values in females and males were TSH >/=10mU/l 0.90% and 0.37%; TSH 4.1-9. 9mU/l 5.1% and 3.7%; and TSH200U/ml) was 13.9% in females and 2.8% in males. In females the lowest percentage (7.9%) of positive TPOAb was seen with TSH 0.2-1.9mU/l and increased both with lower and higher levels of TSH. The percentage of males with positive TPOAb was lower than in females in all TSH groups except for those with TSH>10mU/l (85% TPOAb positive). CONCLUSIONS: In spite of a high prevalence of recognised thyroid disease in the population a considerable number of inhabitants have undiagnosed thyroid dysfunction and also positive TPOAb.

Vitamin D receptor binding and biological effects of cholecalciferol analogues in rat thyroid cells.

The cholecalciferol analogues 1(S),3(R)-dihydroxy-20(R)-[3'(S)-cyclopropyl-3'-hydroxyprop-1'(E)- enyl]-9,10-secopregna-5(Z),7(E),10(19)-triene (calcipotriol, MC 903), 1(S),3(R)-dihydroxy-20(R)-[3'-ethyl-3'-hydroxy- pentoxy]-9,10-secopregna-5(Z),7(E),10(19)-triene (KH 1060) and 1(S),3(R)-dihydroxy-20(R)-[5'-ethyl-5'-hydroxy-hepta- 1',3'(E)-diene-1'-yl]-9,10-secopregna-5(Z),7(E),10(19)-triene (EB 1089) have been modified in the side chain to increase their effects on cell differentiation and proliferation and to reduce the risk of inducing hypercalcemia. The effects of these analogues were tested on FRTL-5 cells, a strain of continuously growing and well-differentiated rat thyroid cells. FRTL-5 cells express a normal vitamin D receptor (VDR), and 1,25-(OH)2D3 potently attenuates the thyrotropin (TSH) stimulated production of the intracellular signalling molecule 3',5'-cyclic adenosine monophosphate (cAMP), iodide uptake and cell growth of these cells. These effects were also induced by the cholecalciferol analogues after 4 days of incubation. KH 1060 was the biologically most potent of the analogues and, compared to KH 1060, the IC50 values were 1.2-, 2.7- and 14-fold higher when 1,25-(OH)2D3, EB 1089 and MC 903, respectively, were used for the displacement of receptor bound [3H]1,25-(OH)2D3. As indicated by their VDR binding, 1,25-(OH)2D3 and EB 1089 were equipotent inhibitors of the TSH stimulated adenylyl cyclase activity, iodide uptake and FRTL-5 cell growth. The analogue MC 903 was the second most potent inhibitor of cell growth in spite of expressing the lowest affinity for the VDR and the weakest inhibition of TSH-stimulated adenylyl cyclase activity and iodide uptake. In conclusion, the biological effects of these cholecalciferol analogues in rat thyroid FRTL-5 cells seem to be mainly determined by their binding affinity for the VDR, although non-genomic effects can not be excluded.

Growth hormone treatment after abdominal surgery decreased carbohydrate oxidation and increased fat oxidation in patients with total parenteral nutrition.

Patients undergoing elective abdominal surgery were double-blindly randomized for treatment with growth hormone (GH) 24 IU (n = 9) or placebo (n = 10) the first 5 postoperative days while receiving total parenteral nutrition (nitrogen, 5.7 +/- .1 g/m2; energy, 1,018 +/- 12 kcal/m2, ie, 125% +/- .7% of basal metabolic rate [BMR]). Carbohydrate and fat metabolism were evaluated from indirect calorimetry, daily blood samples, and forearm substrate-flux studies. Hormone levels in plasma or blood were also determined. GH decreased carbohydrate oxidation, increased fat oxidation, and increased resting energy expenditure (REE). Free fatty acids (FFA), glycerol, and beta-hydroxybutyrate (beta-OH-B) levels increased in both arterial and venous plasma, and forearm release of FFA and glycerol increased. GH, insulin-like growth factor 1 (IGF-1), and glucagon levels in venous blood were also increased in GH-treated patients. Thus, GH induced mobilization and utilization of fat, and fat was preferred to glucose for energy requirements in patients after abdominal surgery with nutritional support.

Bombesin stimulates prolactin secretion from cultured rat pituitary tumour cells (GH4C1) via activation of phospholipase C.

Bombesin (BBS) stimulated prolactin (PRL) secretion from monolayer cultures of rat pituitary tumour cells (GH4C1) in a dose-dependent manner with half maximal and maximal effect at 2 nM and 100 nM, respectively. No additional stimulatory effect on PRL secretion was seen when BBS was combined with thyroliberin (TRH) used in concentrations known to give maximal effects, while the effects of BBS and vasoactive intestinal peptide (VIP) were additive. Using a parafusion system, BBS (1 microM) was found to increase PRL secretion within 4 s and the secretion profiles elicited by BBS and TRH (1 microM) were similar. Both BBS and TRH increased inositoltrisphosphate (IP3) as well as inositolbisphosphate (IP2) formation within 2 s. BBS also induced the same biphasic changes in the electrical membrane properties of GH4C1 cells as TRH, and both peptides caused a rapid and sustained increase in intracellular [Ca2+]. These results suggest that BBS stimulates PRL secretion from the GH4C1 cells via a mechanism involving the immediate formation of IP3 thus resembling the action of TRH.

Effect of Diamphidia toxin, a Bushman arrow poison, on ionic permeability in nucleated cells.

The effect of Diamphidia toxin, isolated from pupae of Diamphidia nigro-ornata, was tested on two different cell lines (GH4C1 cells and HL-60 cells) and on human lymphocytes. The toxin raised intracellular Ca2+ concentration, as assessed with quin 2, in a dose-related manner in all three cell types. The effect was abolished when extracellular Ca2+ was chelated by EGTA. Low concentrations of the toxin evoked a delayed as well as a smaller response. The response time was also temperature-dependent, with a Q10 of about 2. Low, but effective concentrations of the toxin did not affect cell membrane integrity, as tested with Trypan blue, and induced a seemingly physiological release of prolactin from the GH4C1 cells. Diamphidia toxin's effect on the membrane permeability of GH4C1 cells was further investigated with patch-clamp techniques. The toxin appeared to increase the conductance for all small ions without affecting the normal ionic channels present in these cells. We conclude that Diamphidia toxin has a general effect on the plasma membrane of different cell types and thereby increases, probably non-specifically, the permeability for small ions.

Serum N-terminal pro-atrial natriuretic factor 1-98 before and during thyroxine replacement therapy in severe hypothyroidism.

Decreased plasma concentrations of atrial natriuretic factor (ANF) and of its N-terminal prohormones have been demonstrated in severely hypothyroid patients compared with control subjects, and shown to normalize with thyroxine (T4) replacement therapy. Whether this depends on thyroid hormone deficiency exclusively or is secondary to hemodynamic changes that result from it remains a matter of debate. In a recent investigation dose-related increases in both ANF and N-terminal prohormones of ANF by T4 replacement therapy in incremental doses increased at 4-week intervals were demonstrated. It was suggested that thyroid hormones may enhance synthesis rather than release of atrial peptide hormones. The aim of the present study was to confirm this assumption in hypothyroid patients with normal cardiac performance. Serum N-terminal amino acids 1-98 (ie, pro-ANF 1-98) of pro-ANF was determined in 11 severely hypothyroid patients without pericardial effusion and with normal cardiac left ventricular function. Mean pro-ANF 1-98 concentration before T4 replacement therapy remained unchanged after 10 days on T4 (p = .12). After 2 months of therapy, mean pro-ANF 1-98 was significantly increased compared with pretreatment values (p < .003). A significant correlation to the increase in free T4 (r = 0.48, p < .01) but not to the decrease in thyrotropin (TSH) (r = -0.32, p = .09) was found. The present results indicate that thyroid hormones directly increase pro-ANF 1-98 independently of cardiac hemodynamics in the hypothyroid state.