Elevated growth hormone increases the Ca2+ sensitivity of slow- and fast-twitch skeletal muscle of female rats

Auditory changes in acromegaly

OBJECTIVE

The aim of this study is to determine the changes involving auditory system in cases with acromegaly.

MATERIALS AND METHODS

Otological examinations of 41 cases with acromegaly (uncontrolled n = 22, controlled n = 19) were compared with those of age and gender-matched 24 healthy subjects. Whereas the cases with acromegaly underwent examination with pure tone audiometry (PTA), speech audiometry for speech discrimination (SD), tympanometry, stapedius reflex evaluation and otoacoustic emission tests, the control group did only have otological examination and PTA. Additionally, previously performed paranasal sinus-computed tomography of all cases with acromegaly and control subjects were obtained to measure the length of internal acoustic canal (IAC).

RESULTS

PTA values were higher (p < 0.001 for right ears and p = 0.001 for left ears), and SD scores were (p = 0.002 for right ears and p = 0.002 for left ears) lower in acromegalic patients. IAC width in acromegaly group was narrower compared to that in control group (p = 0.03 for right ears and p = 0.02 for left ears). When only cases with acromegaly were taken into consideration, PTA values in left ears had positive correlation with growth hormone and insulin-like growth factor-1 levels (r = 0.4, p = 0.02 and r = 0.3, p = 0.03). Of all cases with acromegaly 13 (32%) had hearing loss in at least one ear, 7 (54%) had sensorineural type and 6 (46%) had conductive type hearing loss.

CONCLUSION

Acromegaly may cause certain changes in the auditory system in cases with acromegaly. The changes in the auditory system may be multifactorial causing both conductive and sensorioneural defects.

Effects of exercise training on insulin-like growth factor-I expression in the skeletal muscle of non-cachectic patients with chronic heart failure

Background Chronic heart failure (CHF) is associated with progressive muscle atrophy and reduced local expression of insulin-like growth factor I (IGF-I).

Design The present study was designed to test the hypothesis that the local deficiency of IGF-I in the skeletal muscle of patients with CHF would respond to a 6-months aerobic training intervention. Therefore, 18 patients [mean age 52.4 (SD 4.8) years, left ventricular ejection function (LVEF) 27 (SD 6)%] were prospectively randomized to either 6 months of training or sedentary lifestyle.

Methods Serum levels of growth hormone (GH) were measured by immunofluorometric assay, IGF-I by competitive solid phase immunoassay. IGF-I expression was assessed in vastus lateralis biopsies by real-time PCR.

Results Exercise training led to a significant increase in peak oxygen uptake by 26% [from 20.3 (SD 3.3) ml/kg per min to 25.5 (SD 5.7) ml/kg per min, P=0.003 versus control]. Local expression of IGF-I increased significantly after exercise training by 81% [from 6.3 (SE 0.8) to 11.4 (SE 1.4) relative units, P=0.007 versus control] while IGF-I receptor expression was reduced by 33% [from 20.0 (SE 2.1) to 13.8 (SE 1.7) relative units, P=0.008 versus control]. Serum growth hormone (GH) rose modestly from 0.12 (SE 0.07) to 0.65 (SE 0.37) ng/ml in the training group ( P=0.043 versus baseline), however, this change was not significant compared to the control group ( P=0.848). IGF-I serum levels remained virtually unchanged.

Conclusions Exercise training improves local IGF-I expression without significant changes of systemic parameters of the GH/IGF-I axis. These findings indicate that exercise training has the therapeutic potential to attenuate peripheral skeletal muscle alterations in particular with respect to local IGF-I expression in patients with moderate CHF.

Expeditious synthesis and biological evaluation of new C-6 1,2,3-triazole adenosine derivatives A1 receptor antagonists or agonists

The synthesis of new C-6 1,2,3-triazole adenosine derivatives via microwave assisted 1,3-dipolar cycloaddition as key step is described. The binding on membranes of cells that over express A(1) adenosine receptors (A(1)AR) was also evaluated. Among them, four compounds increased cAMP production, in a dose-dependent manner acting as antagonists of the A(1)AR, while two compounds act as agonists.

Adenosine deaminase-acid phosphatase association and the environment: A study in a continental Italian population

Three hundred fifty newborns from Rome and 351 from Penne were studied in continental Italy. Medium high altitude above sea level and cold winters characterize the area of Penne, while low altitude and very mild winters characterize the area of Rome. An effect of environmental conditions on the association between adenosine deaminase (ADA) and acid phosphatase (ACP1), previously shown in Sardinia, has been confirmed in continental Italy. When compared with expected independent assortment, the proportion of ACP1*A/*A carrying the ADA*2 allele is lower than expected in the lowlands and higher than expected in highlands. In continental Italy there is an interaction among ACP1-ADA genotype, season of conception, and locality. The excess of *A/*A newborns carrying the ADA*2 allele is present only among those conceived in the first half of the year (January-June). Among newborns in Penne conceived in the Spring, the proportion of those with *A/*A genotype is increased and these infants show decreased intrauterine growth. The present data suggest that ADA and ACP1 interact during intrauterine life with effects on development and survival and that such effects are dependent on local environment and season of conception. Am. J. Hum. Biol. 12:214-220, 2000. Copyright 2000 Wiley-Liss, Inc.