The onset of puberty and the availability of sex steroids in female gymnasts

Plasma levels of gonadotropins, (sex) steroids, SHBG bound fractions of 17β-estradiol (E2) and testosterone (T), and sex-hormone-binding globulin (SHBG) were compared at the onset of puberty in female gymnasts (n = 7) and two groups of schoolgirls with similar anthropometric characteristics. Ten schoolgirls were matched to the gymnasts on the basis of a sum of skinfolds and the waist/hip ratio, while 12 other girls were selected on the basis of the stature and bicristal breadth of the female gymnasts. All girls were in the second stage of breast development (M2) and were classified as being in the first stage (M1) 6 months earlier. When female gymnasts were compared to nonathletic schoolgirls with similar physical characteristics at the same stage of early puberty, the former had significantly lower levels of plasma luteinizing hormone (LH), total and available E2, and T. In conclusion, female gymnasts have significantly lower LH, E2, and T plasma levels than nonathletic schoolgirls in early puberty. The E2 and T plasma levels in early female gymnasts are not related to the individual physical characteristics, i.e., fat mass, short stature, or small bicristal breadth. © 1993 Wiley-Liss, Inc.     

Effects of chronic intensive training on androgenic and cortisol profiles in premenarchal female gymnasts

The effect of intensive exercise training on urinary androgen and cortisol excretions in prepubertal girls of various ages was tested in competitive premenarchal gymnasts (n=56) and in age-matched controls (n=53). Both sexual maturation and bone age were assessed. Urinary excretions of androstenedione, dehydroepiandrosterone sulphate (DHEA-S), testosterone and cortisol were determined by radioimmunoassay procedures. The gymnasts were taller [mean (SD) 138.3 (9.0) cm vs 144.7 (8.3) cm; P<0.001] and lighter [32.0 (6.9) kg vs 36.7 (8.2) kg; P<0.001], and had a lower percentage of fat mass [16.8 (2.2)% vs 22.5 (6.6)%; P<0.0001] than the controls. There was no difference between groups in urinary testosterone, cortisol and DHEA-S levels, while androstenedione levels were significantly lower in gymnasts than in controls [mean (SEM) 187.10 (18.00) nmol/24 h vs 256.50 (15.00) nmol/24 h; P<0.01). There was no difference in the regression slopes between the two groups for all hormonal values. In conclusion, these results suggest that during the prepubertal period, intensive training alters only urinary androstenedione concentrations in girls. Electronic Publication     

Sex hormone status of the postmenopausal woman

Plasma levels of testosterone, androstenedione, dehydroepiandrosterone and its sulphate, and of androstenediol, as well as estrone and estradiol, were determined in several groups of postmenopausal women.The ovaries contribute to plasma estrogen levels only early in the postmenopause, but continue to secrete testosterone and minimal amounts of androstenedione throughout the postmenopause.With age there is a decreased secretion by the adrenal of dehydroepiandrosterone (sulphate) and of androstenediol.The levels of androstenedione and estrone and the androstenedione/estrone ratio remain unchanged with increasing age. The levels of estrone and estradiol, and the ratios, estrone/androstenedione and estradiol/testosterone, are correlated with fat mass. There is also an inverse curvilinear relationship with precursor concentration. This suggests either a progressive saturation of the tissular aromatase with increasing precursor level, or the existence of an unknown estrogen precursor.     

Relation of the secretion of growth hormone (GH), somatomedin C/IGF I (IGF I) and steroids before and after the beginning of puberty in patients of short stature

Somatomedin C/IGF I, dehydroepiandrosterone sulfate (DHAS), testosterone (T) or estradiol (E2) have been measured in 154 patients of a previous study in which growth hormone (GH) responses to classical pharmacologic stimuli and spontaneous growth hormone secretion during sleep were compared in short children before and at the beginning of puberty. Five groups were identified: Group I, normal growth hormone secreting children; group II, completely growth hormone deficient; group III, partially growth hormone deficient; group IV, with normal sleep secretion and low responses to stimuli; group V, with the reverse situation. The somatomedin C/IGF I levels were widely dispersed. In group I, the mean +/- SEM levels of somatomedin C/IGF I were 0.77 +/- 0.047 U/ml before puberty and 1.36 +/- 0.142 U/ml in early pubertal patients, with a relation to age (r = 0.52, p less than 0.001). The difference between prepubertal and pubertal patients was significant. In groups II to V, there was no pubertal rise of somatomedin C/IGF I. In group II, the mean IGF I level was 0.48 +/- 0.05 U/ml, significantly lower than in prepubertal patients of group I. In groups III, IV and V, it was 0.7 +/- 0.069 U/ml, 0.8 +/- 0.059 U/ml, and 0.73 +/- 0.059 U/ml respectively, not different from prepubertal patients of group I, but significantly lower than in early pubertal patients of the same group. In prepubertal patients, somatomedin C/IGFI was slightly but highly significantly correlated to the growth hormone sleep secretion (r = 0.27, p less than 0.001) and to dehydroepiandrosterone sulfate (r = 0.36, p less than 0.001), but growth hormone and dehydroepiandrosterone sulfate were not correlated together.(ABSTRACT TRUNCATED AT 250 WORDS)     

Beta-endorphin and ACTH levels in peripheral blood during and after aerobic and anaerobic exercise

Summary Beta-endorphin (-End) and adrenocorticotrophic hormone (ACTH) were determined in the peripheral blood of 14 human volunteers exercising on a bicycle ergometer. After 1 h of submaximal work below anaerobic threshold (AT), defined as the 4 mmol · l^–1 lactic acid level in arteriolar blood (Kindermann 1979; Mader 1980), -End and ACTH levels did not change from control conditions. Eleven of the same 14 subjects performed an uninterrupted graded exercise test on the same bicycle ergometer until exhaustion. This time -End and ACTH levels increased concomitantly with exercise of high intensity: at each moment, during and after this maximal test, a highly significant correlation (P<0.0001) was noted between the levels of - End and ACTH. The peak values of these hormones were reached within 10 min after stopping maximal exercise, and coincided with lactic acid peak levels. A rise in lactic acid levels above the anaerobic threshold always preceded the exercise-induced rise in -End and ACTH. Within the population tested, two subgroups could be distinguished: one comprising individuals whose hormonal response nearly coincided with the rise in lactic acid (rapid responders) and a second group composed of subjects whose normal response appeared delayed with respect to the lactic acid rise (slow responders). These results support the view that -End and ACTH are secreted in equimolar quantities into the blood circulation in response to exercise, and suggest that metabolic changes of anaerobiosis play a key role in the regulation of stress-hormone release. In view of the variable time of onset of hormonal response, it seems likely that complex regulatory mechanisms are operative.     

Β-Adrenoceptor density on mononuclear leukocytes and right atrial myocardium in infants and children with congenital heart disease

Summary Sympathetic regulation of myocardial performance has been shown to be altered in congestive heart failure. Right atrial tissue of children with severe acyanotic and cyanotic congenital heart disease (CHD) showed a significantly lower-receptor density than that of children with less severe defects. Since mononuclear leukocytes (MNL) contain a homogeneous population of ₂-adrenoceptors which have similar properties to those of cardiac ₂-adrenoceptors, they are frequently used for studying the-adrenergic system. In a group of 37 children with CHD of different types and severity who underwent cardiac surgery, we compared the MNL-adrenoceptor density to the type and severity of CHD and looked for a possible relationship to plasma catecholamine levels and to the right atrial-adrenoceptor density. Membranes of MNL and myocardial cells were radiolabeled with (–)3-[¹²⁵I]Iodocyanopindolol ([¹²⁵I]ICYP). A significantly higher-adrenoceptor density on MNL was found in patients with moderate acyanotic CHD (group I) than in those with severe acyanotic (group II) and cyanotic CHD (group III). Patients of group I showed approximatively 50% higher myocardial-receptor density than those of groups II and III. ICI 118.551-[¹²⁵I]ICYP competition studies revealed that in groups II and III significantly lower proportions and densities of ₁-receptors were found compared to group I. Noradrenaline (NA) plasma levels in group II and group III were significantly higher than those in group I. The adrenaline plasma levels were found to be very high in all children with CHD. A significant negative correlation between NA levels and myocardial total and ₁-adrenoceptor density, but no correlation between plasma catecholamines and MNL-adrenoceptor density, was calculated. We conclude that modulation of MNL-adrenoceptors is not simply controlled by circulating catecholamine levels. Cardiac ₂-adrenoceptor density remained unaltered, but the ₁-density was significantly lowered. ₂-adrenoceptors on MNL showed a slight but significant decrease. However, cardiac ₂-adrenoceptor density cannot be predicted by measuring the-adrenoceptor density on MNL.Abbreviations CHD Congenital heart disease - MNL mononuclear leukocytes - NA noradrenaline - P_PA/P_AO Ratio between pulmonary and aortic pressure - Qp/Qs Ratio between pulmonary and systemic blood flow - HPLC-ED High performance liquid chromatography with electrochemical detector     

Metabolic and hormonal responses to exhaustive supramaximal running with and without Β-adrenergic blockade

Summary The metabolic and hormonal responses to exhaustive short-term supramaximal exercise were studied in 10 male physical education students. The exercise task was a single bout of running on the treadmill at 22 km·h^–1 and 7.5% slope. It was performed with single oral doses of 100 mg Bupranolol (non-selective -blockade), 100 mg Metoprolol (-1-selective blockade), and placebo. Arterialized capillary and venous blood were sampled until 30 min post exercise.Time to exhaustion was 52.0±2.6, 47.6±2.0, and 46.0±1.9 s in the control, Metroprolol, and Bupranolol experiments. At cessation of exercise, adrenaline and noradrenaline were grossly elevated in all three conditions. Lactate and glucose increased markedly, this being accompanied by increasing insulin in the control and Metoprolol, but not the Bupranolol trials. Glycerol increased moderately, while FFA were depressed. Growth hormone showed a delayed increase at 15 and 30 min post exercise. Cortisol was unaffected by exercise. -blockade reduced the increases of lactate, glucose, glycerol, insulin, and growth hormone, exaggerated the depression of FFA and had no effect on cortisol.The results demonstrate that the strong sympatho-adrenal response to exercise of this nature is a major determinant of the increase of glucose at cessation of exercise. The hyperglycemia in concert with -2-adrenergic stimulation leads to elevation of insulin. Furthermore, lipolysis is controlled by -adrenergic stimulation. The delayed increase of growth hormone seems to be triggered by the declining glucose level during recovery.Supported by Bundesinstitut für Sportwissenschaft, Köln-Lövenich     

Impaired insulin action in puberty. A contributing factor to poor glycemic control in adolescents with diabetes

Patients with insulin-dependent diabetes mellitus often have poor metabolic control during puberty. To determine whether puberty is associated with decreased insulin-stimulated glucose metabolism, we compared the results of euglycemic insulin-clamp studies in adults and prepubertal and pubertal children with and without insulin-dependent diabetes. In nondiabetic pubertal children, insulin-stimulated glucose metabolism (201 +/- 12 mg per square meter of body surface area per minute) was sharply reduced, as compared with that of prepubertal children and adults (316 +/- 34 and 290 +/- 21 mg per square meter, respectively; P less than 0.01), despite comparable hyperinsulinemia (insulin levels of 80 to 90 microU per milliliter). Similarly, the response to insulin was 25 to 30 percent lower in the diabetic pubertal children than in the diabetic prepubertal children (P less than 0.05) and adults (P = 0.07). At each stage of development, the stimulating effect of insulin on glucose metabolism was decreased by 33 to 42 percent in the children with diabetes (P less than 0.01). In all the groups of children studied, the response to insulin was inversely correlated with mean 24-hour levels of growth hormone (r = -0.52, P = 0.01). Among the diabetic children, the glycosylated hemoglobin levels were substantially higher in the pubertal children than in the prepubertal children (P less than 0.02), although the daily insulin doses tended to be higher. These data suggest that insulin resistance occurs during puberty in both normal children and children with diabetes. The combined adverse effects of puberty and diabetes on insulin action may help explain why control of glycemia is so difficult to achieve in adolescent patients.     

Hirsutism, polycystic ovarian disease, and ovarian 17-ketosteroid reductase deficiency

We studied an 18-year-old woman with progressive hirsutism, secondary amenorrhea, and polycystic ovarian disease. Excess androstenedione was secreted by the ovaries, most likely because of a genetic deficiency of ovarian 17-ketosteroid reductase, the enzyme that converts androstenedione to testosterone. Markedly elevated basal plasma levels of androstenedione, estrone, and testosterone were regulated by gonadotropin but not by ACTH. The rate of androstenedione production in the patient's blood at base line and after administration of dexamethasone was very high (10.0 to 11.6 mg per day; value in control women with hirsutism, less than 4.1 mg per day), whereas her blood production of testosterone was 0.64 to 0.7 mg per day, similar to or higher than that in control women with hirsutism. The fractional blood conversion ratio of androstenedione to testosterone was normal (5.6 percent). Thus, 88 to 93 percent of the testosterone in the blood was derived from the peripheral conversion of androstenedione, and very little testosterone was secreted by the ovaries. These in vivo biochemical data suggest that the patient had a deficiency of ovarian 17-ketosteroid reductase activity but normal pubertal activity. The patient's two younger sisters with peripubertal symptoms of androgen excess also had elevated serum levels of androstenedione. We propose that the increased secretion of androstenedione in the three siblings in this family was probably due to a genetic deficiency of ovarian 17-ketosteroid reductase.     

Relationships of sex hormone levels to dependence in activities of daily living in the frail elderly

OBJECTIVES: We undertook this nursing home study in order to determine the relationships between dependency in activities of daily living (ADL) and blood levels of estrone, testosterone, androstenedione, and dehydroepiandrosterone (DHEA). Little is known about this issue. METHODS: cross-sectional study of 370 nursing home residents. Hormone levels in blood specimens drawn in 1997 and 1998 were correlated with degree of ADL dependency recorded in medical charts. RESULTS: Because of multiple comparisons associations were deemed significant for P-values < or =0.017 for males and < or =0.0125 for females. In males, the following were inversely related: testosterone levels with dependency in transferring and eating; estrone with eating and a summary ADL index; and androstenedione with toileting and a summary ADL index (in all cases, r=-0.4; P=0.007-0.015). Inverse trends existed between testosterone levels and dependency in mobility and a summary ADL index; and androstenedione and eating (in all cases r=-0.3; P=0.030-0.055). Among females the following were directly related: estrone levels with dependence in mobility, toileting, transferring, and a summary ADL index; and DHEA with transferring and a summary ADL index (r=0.2-0.3, P=0.0001-0.01). Trends existed between estrone and eating, and DHEA and toileting (r=0.1-0.2, P=0.04). CONCLUSION: In male residents, higher sex hormone levels are associated with better ADL performance. Among females the opposite is true. While further studies are needed to elucidate these relationships, our results and recent findings of others suggest sex hormone actions in older women differ from those in younger populations. A possible stress-related mechanism is also presented.     

Β2-microglobulin secretion from lymphoid cells: A study at the cellular level

A protein plaque assay was developed for the detection of human lymphocytes secreting ₂-microglobulin. The development of plaques required production of ₂-microglobulin by viable cells at an estimated rate exceeding 25 molecules per second. It has previously been suggested that ₂-microglobulin secretion is restricted to certain lymphoid cell subpopulations. However, both T- and B-cells were shown to form plaques in normal donors and immunodeficient patients after activation with various mitogens.A close correlation between ₂-microglobulin production and DNA synthesis was evident. However, secretion of immunoglobulin did not correlate with the proportion of cells secreting ₂-microglobulin.     

Evaluation of mental task strain based on occipital beta activity and subjective rating of task difficulty

Summary Occipital midline beta-2 (Oz₂) amplitudes and subjective ratings of task difficulty were measured in 24 healthy male students, aged 19–23 years, performing four kinds of mental task (transcribing, cancelling, adding, and calculating) at two grades of self-pace (maximum workload and moderate workload) for 5 min each.Significant differences in Oz₂ amplitudes were observed between the tasks at either workload, except between the adding task and the calculating task. However no significant difference in the subjective ratings was observed between the tasks at either workload, except between the adding task and the calculating task or the cancelling task at maximum workload. Thus the Oz₂ amplitude was more sensitive to differentiation of task strain between the mental tasks, than the subjective rating. In comparison with the critical levels deduced previously, it was estimated from the Oz₂ amplitudes that all the tasks at either workload could induce heavy task strain in the subject, except for the cancelling task at moderate workload. From the subjective ratings, however, it was estimated that no task could induce heavy task strain in the subject.It was, moreover, suggested that the Oz₂ amplitudes reflected the difference in the quality of cortical functions and that the subjective ratings of task difficulty were associated with time pressure rather than the quality of cortical functions.     

Socio-economic factors in relation to lipid profiles in young girl athletes

Summary The influence of socio-economic factors on blood lipid values was studied in 4 groups of young female athletes. Based on type of sport (gymnastics and swimming) and of training intensity, the participants were subdivided into 25 talented, high achievement gymnasts (age 12.3±1.6 (SD) year), 42 non-talented, low achievement gymnasts (age 12.0±1.2 (SD) year), 12 high achievement swimmers (age 10.3±1.6 (SD) year), and 24 low achievement swimmers (age 10.8±1.6 (SD) year). With respect to socio-economic factors, no significant differences were observed between the two gymnastic groups nor between the two swimming groups. The blood lipid values revealed a significantly higher low density lipoprotein-cholesterol level and significantly lower high density lipoprotein-cholesterol/total cholesterol and high density lipoprotein-cholesterol/low density lipoprotein cholesterol ratios in the talented gymnasts as compared to the non-talented gymnasts. In the high achievement swimmers, low density lipoprotein-cholesterol and triglyceride levels were significantly lower and high density lipoprotein-cholesterol/total cholesterol was significantly higher as compared to the other swimmers. The Spearman rank order correlation coefficients for the relationships between socio-economic factors and blood lipid values were mostly weak or inconsistent. Therefore, no major influence of socio-economic factors on blood lipid values could be demonstrated in the groups investigated.     

Β-Glucuronidase activity in trained red and white skeletal muscle of mice

Summary We studied the effects of prolonged running exercise (5 days a week, 1.5 h per day at a speed of 17.6 m/min) on the activity of some acid hydrolases (-glucuronidase, -N-acetylglucosaminidase, acid phosphatase and cathepsin D) and three enzymes of energy metabolism (cytochrome c oxidase, lactate dehydrogenase and creatine kinase) in the distal and in the proximal, the predominantly white and red parts, respectively, of the vastus lateralis-muscle from mice. The acid hydrolase activity levels were 1.24–1.69 higher in untrained red muscle compared to untrained white muscle. The light training applied increased the activity of -glucuronidase in both red and white muscle. No other significant training effects were observed in the enzyme activities measured.     

Longitudinal assessment of hormonal and physical alterations during normal puberty in boys. VI. Modeling of growth velocity,mean growth hormone (GH mean), and serum testosterone (T) concentrations

The growth and hormonal status of 23 prepubertal and early pubertal normally growing boys were evaluated for at least 6 years as they entered and progressed through puberty. Each subject was observed during a 24-hr hospital admission approximately every 4 months. Standing height was measured upon arising. At the same time an early morning (0600hr) serum level of testosterone was obtained. A mean growth hormone level was determined from a pool of equal quantities of serum from 72 samples obtained every 20 min for 24 hr. The early morning testosterone level was used as an index of pubertal status. The effect of the chronological age, mean growth hormone, and testosterone levels on the growth velocity was investigated. In addition to age, the interaction between the mean growth hormone level and testosterone concentration has a significant effect on the velocity of growth. Several nonlinear models were explored to describe growth velocity, mean growth hormone level, and testosterone concentration in terms of chronological age of each subject. Models used were chosen for simplicity, interpretability of the model itself and its parameters, and the ability to estimate (and then test) the parameters. Unknown parameters of the model were estimated using ordinary least squares (OLS), which minimizes the L₂ norm of the observed and the predicted values. The L₂ norm may be unduly influenced by outlying observations which commonly occur in many biological data sets. Hence, in addition to the OLS estimators, the least absolute deviation (LAD) estimator which minimizes the L₁ norm of the observed and the predicted values was also considered. Typically, the LAD estimators are more robust than OLS estimators. From a clinical point of view it may be important to know the “normal” values of growth velocity, mean growth hormone level, and testosterone at a given age during puberty. For this reason population models for each of these variables along with their 90% confidence regions were developed. These will permit identification of those children who are outside the boundaries of normal growth for the purpose of evaluation for the etiology of the deviation. Am. J. Hum. Biol. 12:814–824, 2000. © 2000 Wiley-Liss, Inc.     

Transforming growth factor Β1 influences glycosylation of α1-protease inhibitor in human hepatoma cell lines

We have previously shown that changes in acute-phase protein glycosylation result from alterations occurring within hepatocytes as a result of regulation by cytokines, that the glycosylation patterns of proteins secreted by Hep 3B and Hep G2 cells respond differently to the crude mixtures of cytokines found in conditioned medium from LPS-stimulated monocytes, and that interleukin-6 (IL-6) causes increased concanavalin A (Con A) binding ofl protease inhibitor in Hep 3B cells and decreased Con A binding of this protein in Hep G2 cells. In the present study we found that transforming growth factorl (TGF-), like IL-6, led to secretion of forms ofl-protease inhibitor with increased Con A binding in Hep 3B cells, and that IL-6 and TGF- in combination were additive. In contrast, in Hep G2 cells, TGF- had an effect opposite to that produced by IL-6, leading to secretion of forms ofl-protease inhibitor with increased Con A binding. When employed in combination with IL-6, TGF- abolished the effect of that cytokine. These studies indicate that TGF- influences glycosylation of al-protease inhibitor in two human hepatoma cell lines in a manner that can be differentiated from that of IL-6. The identification of TGF- as a second defined cytokine capable of influencing glycoprotein glycosylation and the demonstration that the effect of one cytokine can be modulated by another cytokine support the view that changes in glycosylation of plasma proteins are mediated by combinations of cytokines.     

Ontogeny of gonadotrophin and inhibin secretion in normal girls through puberty based on overnight serial sampling and a comparison with normal boys

We measured luteinizing hormone (LH) and follicle stimulating hormone (FSH) by immunofluorometric assays and alpha-inhibin by radioimmunoassay in serum sampled every 10 min throughout the night (2100-0500 h) from 44 normal girls. Mean overnight LH values rose log- linearly from a mean of 0.2 IU/l in prepubertal girls to 3.0 IU/l in late pubertal girls. Log2 mean overnight FSH rose rapidly through early puberty and then remained constant; mean FSH rose from 1.0 IU/l in prepubertal girls to approximately 2.8 IU/l in Tanner III-V girls. Mean overnight inhibin increased through puberty, rising from 151 ng/l in prepubertal girls to 432 ng/l in fully pubescent girls. Within each of the first three Tanner stages, LH differed approximately 100-fold between the smallest and largest mean concentrations but differed <10- fold within stages IV or V. Such within-pubertal stage variability was less pronounced for FSH, which differed approximately 16-fold among Tanner I subjects and 4-10-fold at later stages, and for inhibin, which varied approximately 4-fold within each Tanner stage. The frequency of LH pulses during overnight sampling increased significantly during puberty, but the frequency of FSH and inhibin pulses remained constant. We compared the results from girls to those from 50 normal boys [Manasco et al. (1995) J. Clin. Endocrinol. Metab., 80, 20462052]. At each pubertal stage, girls had approximately the same mean overnight LH values as boys; girls had higher mean overnight FSH, particularly during Tanner stages II-IV; and boys had mean overnight alpha-inhibin immunoreactivity approximately 1.5 times that of girls at each pubertal stage. Still, hormone concentrations for individuals of both sexes intergraded at each pubertal stage.      

Association of dystroglycan and laminin-2 coexpression with myelinogenesis in peripheral nerves

To provide clues to the biological functions of dystroglycan–laminin-2 complex in peripheral nerves, we investigated the expressions of -dystroglycan and laminin-₂ chain in rat sciatic nerve during axonal degeneration and regeneration and during development, as well as in rat dorsal root ganglia. In normal conditions, immunoreactivity of the cytoplasmic domain of -dystroglycan was associated with the Schwann cell abaxonal membrane. The immunoreactivities of both -dystroglycan and the laminin-₂ chain decreased in Schwann cells losing axons during axonal degeneration and progressively increased in remyelinating Schwann cells during axonal regeneration. Interestingly, during axonal degeneration, the abaxonal membrane losing contact with the basal lamina lost the association with -dystroglycan immunoreactivity. During development, expression of both -dystroglycan and laminin-₂ chain strikingly increased during postnatal 7 days, which is a critical period when basal lamina assembly and myelin formation rapidly progress. These results suggest that coexpression of dystroglycan and laminin-2 is associated with myelinogenesis in peripheral nerves. These two proteins may function as an anchorage between the abaxonal membrane and the basal lamina, enabling myelin forma-tion to progress. -Dystroglycan and laminin-2 were also coexpressed in satellite cells in dorsal root ganglia, suggesting that interaction of these two proteins plays some role in physiological functions of these cells.     

Effect of alpha-2-macroglobulin on cytokine-mediated human C-reactive protein production

Alpha-2-macroglobulin (2-M), a serum protease inhibitor that also binds cytokines, neutralized the inhibitory effect exerted by transforming growth factor- (TGF-) on IL-6-induced C-reactive protein (CRP) production by the human hepatoma cell line PLC/PRF/5. 2-M was found to bind noncovalently with TGF- to form a complex that, upon acidification, released TGF- inhibitory activity as detected by IL-6-induced CRP production. Although 2-M also binds IL-6, it did not alter IL-6-induced CRP production by the hepatoma cells. The interaction between 2-M and TGF- may influence the production of acute-phase proteins by liver hepatocytes.This study was presented in part at the AAI/ASBMB Meeting, June 3–7, 1990, New Orleans, Louisiana. Supported by USPHS grant CA 30015.