Quantitative encapsulation and retention of 227Th and decay daughters in core-shell lanthanum phosphate nanoparticles

Targeted alpha therapy (TAT) offers great promise for treating recalcitrant tumors and micrometastatic cancers. One drawback of TAT is the potential damage to normal tissues and organs due to the relocation of decay daughters from the treatment site. The present study evaluates La(227Th)PO4 core (C) and core +2 shells (C2S) nanoparticles (NPs) as a delivery platform of 227Th to minimize systemic distribution of decay daughters, 223Ra and 211Pb. In vitro retention of decay daughters within La(227Th)PO4 C NPs was influenced by the concentration of reagents used during synthesis, in which the leakage of 223Ra was between 0.4 ± 0.2% and 20.3 ± 1.1% in deionized water. Deposition of two nonradioactive LaPO4 shells onto La(227Th)PO4 C NPs increased the retention of decay daughters to >99.75%. The toxicity of the nonradioactive LaPO4 C and C2S NP delivery platforms was examined in a mammalian breast cancer cell line, BT-474. No significant decrease in cell viability was observed for a monolayer of BT-474 cells for NP concentrations below 233.9 μg mL-1, however cell viability decreased below 60% when BT-474 spheroids were incubated with either LaPO4 C or C2S NPs at concentrations exceeding 29.2 μg mL-1. La(227Th)PO4 C2S NPs exhibit a high encapsulation and in vitro retention of radionuclides with limited contribution to cellular cytotoxicity for TAT applications.

Accumulation of ENOD2-like transcripts in non-nodulating woody papilionoid legumes

Japanese pagodatree (Styphnolobium japonicum [L.] Schott) and American yellowwood (Cladrastis kentukea Dum.-Cours.) Rudd are the first woody, non-nodulating papilionoid legumes shown to possess putative early nodulin 2 (ENOD2) genes. ENOD2 cDNAs from Japanese pagodatree (807 bp) and American yellowwood (735 bp) have 75% to 79% sequence identity to ENOD2 sequences and encode deduced proteins that possess conserved ENOD2 pentapeptides (PPHEK and PPEYQ). Lower percentages of glucose and higher percentages of histidine and valine suggest that SjENOD2 and CkENOD2 are different from other ENOD2s. Hybridization analyses indicate the clones represent ENOD2 gene families of two to four genes in Japanese pagodatree and American yellowwood genomes, and ENOD2-like transcripts were detected in stems and flowers, as well as roots. Only roots of control species that nodulate, Maackia amurensis Rupr. & Maxim. and alfalfa (Medicago sativa), produced pseudonodules after treatment with zeatin or 2,3,5-triiodobenzoic acid, an auxin transport inhibitor. Accumulation of MaENOD2 transcripts was enhanced during the first 10 d of treatment, but 2,3,5-triiodobenzoic acid and zeatin enhanced transcript accumulation after 30 d in roots of Japanese pagodatree and American yellowwood. Characteristics that distinguish ENOD2 gene families in basal, non-nodulating woody legumes from other ENOD2 genes may provide new information about the function of these genes during symbiotic and non-symbiotic organ development.

Changes in serum inhibin, activin and follistatin concentrations during puberty in girls

Serum concentrations of inhibin A, inhibin B, activin A and follistatin were determined using two-site enzyme-linked immunosorbent assays (ELISA) during pubertal ovarian development in 28 girls and five follicular phase women. Blood obtained every 15 to 20 min overnight was pooled for peptide determination. Serum inhibin A concentrations increased in mid puberty, exhibiting positive correlations with bone age (r = 0.527, P = 0.0016) and oestradiol concentrations (r = 0.581, P = 0.0005). Inhibin B concentrations peaked in mid puberty and declined thereafter, but remained greater than concentrations seen in prepubertal girls, and correlating positively with oestradiol (r = 0.362, P = 0.046) and follicle stimulating hormone (FSH) concentrations (r = 0.369, P = 0.038). Total activin A concentrations did not vary significantly across pubertal stages. Total follistatin concentrations, determined by radioimmunoassay, decreased with advancing puberty, exhibiting negative correlations with bone age (r = -0.634, P = 0.0001) and oestradiol concentration (r = -0.687, P = 0.0001). Follistatin concentrations determined by an ELISA specific for follistatin 288 were greatest in mid-pubertal girls, but concentrations in late puberty were less than those in early puberty. The free follistatin assay indicated that all circulating follistatin was activin-bound. These results suggest that significant changes in serum concentrations of FSH-regulatory peptides accompany the onset of puberty.

In pubertal girls, naloxone fails to reverse the suppression of luteinizing hormone secretion by estradiol

Estradiol (E2) negative feedback on LH secretion was examined in 10 pubertal girls, testing the hypothesis that E2 suppresses LH pulse frequency and amplitude through opioid pathways. At 1000 h, a 32-h saline infusion was given, followed 1 week later by an E2 infusion at 13.8 nmol/m2 x h. During both infusions, four iv boluses of saline were given hourly beginning at 1200 h, and four naloxone iv boluses (0.1 mg/kg each) were given hourly beginning at 1200 h on the following day. Blood was obtained every 15 min for LH determination and every 60 min for E2 determination from 1200 h to the end of the infusion. E2 infusion increased the mean serum E2 concentration from 44+/-17 to 112+/-26 pmol/L (P < 0.01). The mean LH concentration between 2200-1200 h decreased from 3.19+/-0.89 to 1.99+/-0.65 IU/L (P = 0.014), and LH pulse amplitude decreased from 3.4+/-0.6 to 2.6+/-0.5 IU/L (P = 0.0076). Although there were 1.2 fewer pulses during E2 infusion compared to saline infusion, differences did not reach significance (P = 0.1; 95% confidence interval for the difference, -3.5, 1.1). Pituitary responsiveness to GnRH, assessed at the end of the infusion by administering 250 ng/kg GnRH iv, did not change during E2 infusion. The effect of naloxone blockade of opioid activity on LH secretion was determined by assessing the area under the curve (AUC) from 1200-1600 h. During saline infusion, the LH AUC was 1122+/-375 IU/L during saline boluses and 1575+/-403 IU/L during naloxone boluses (P = 0.39). When E2 was infused, the LH AUCs during saline and naloxone boluses were 865+/-249 and 866+/-250 IU/L, respectively. Thus, in pubertal girls: 1) E2 decreases the LH concentration and LH pulse amplitude; 2) the main site of negative feedback effect of E2 appears to be at the level of the hypothalamus; 3) an increase in LH secretion after naloxone administration could not be demonstrated in these girls and may depend on the maturity of the hypothalamic-pituitary-gonadal axis; and 4) opioid receptor blockade does not reverse the E2 inhibition of LH secretion even in the most mature girls. Thus, E2 suppression of LH secretion in pubertal girls appears to be mediated by a decrease in hypothalamic GnRH secretion that is independent of opioid pathways.

Utilization of microhomologous recombination in yeast to generate targeting constructs for mammalian genes

We have developed a new procedure utilizing microhomologous recombination in yeast to generate targeting constructs for producing targeted mutations in mice. This procedure is rapid and efficient, and should be directly applicable to all mammalian genes. Moreover, only minimal information about the locus being targeted is required. The feasibility of this approach was demonstrated by producing another allele of the mouse Tg737 polycystic kidney gene.

Acute effects of estradiol infusion and naloxone on luteinizing hormone secretion in pubertal boys

We have shown previously in pubertal boys that testosterone (T) suppresses the nocturnal augmentation of luteinizing hormone (LH) secretion principally by decreasing LH pulse frequency. As T can be aromatised to estradiol (E2), and E2 effects on LH secretory dynamics may be separate from those of T, we examined the effects of acute E2 infusion on LH secretion in pubertal boys. Opioid receptor blockade has been reported to increase LH secretion after estradiol suppression in adult men, so we also examined whether naloxone might augment LH secretion during E2 treatment in pubertal boys. Starting at 1000 h, eight pubertal boys were given a 33 h saline infusion, followed 1 week later by an E2 infusion at 4.6 nmol/m2/h. During both infusions, four iv boluses of saline were given hourly beginning at 1200 h on the first day, and four naloxone iv boluses, 0.1 mg/kg each, were given hourly beginning at 1200 h on the second day. Blood was obtained every 15 min for LH, and every 60 min for T and E2, from 1200 h until the end of the infusion. Pituitary responsiveness to gonadotropin-releasing hormone (GnRH) was assessed after both infusions by iv administration of 250 ng/kg synthetic GnRH. Estradiol infusion increased the mean plasma E2 concentration from 23 +/- 4 to 46 +/- 6 pmol/L (P < 0.01) and suppressed mean plasma T from 4.9 +/- 1.4 to 3.0 +/- 3.5 nmol/L (saline vs. E2 infusion, P < 0.05). The overall mean LH was suppressed by E2 infusion from 3.7 +/- 0.5 to 2.2 +/- 0.4 IU/L (saline vs. E2 infusion, P < 0.01). LH pulse frequency was suppressed by 50%, whereas mean LH pulse amplitude was not different between saline and E2 infusions. Administration of naloxone did not alter the mean LH, LH pulse frequency, or amplitude during either saline or E2 infusions. Pituitary responsiveness to exogenous GnRH was similar during both infusions. These studies indicate that E2 produces its negative feedback in pubertal boys principally by suppression of LH pulse frequency, and naloxone does not reverse these suppressive effects. Thus E2 suppression of LH secretion is mediated by a decrease of hypothalamic GnRH secretion that is independent of endogenous opioid pathways.

Changes in serum immunoreactive and bioactive growth hormone concentrations in boys with advancing puberty and in response to a 20-hour estradiol infusion

Acceleration of linear growth during puberty is associated with increased GH secretion, although the relationship between growth and GH is complex. As GH exists as a family of isoforms, some of which may not be identified by immunoassay, there may be alterations in isoform secretion during pubertal maturation that result in increased growth. The changes in serum immunoreactive and bioactive GH concentrations across pubertal maturation were determined in 30 boys, aged 6.5-19.3 yr, with idiopathic short stature or constitutional delay of adolescence. Data were grouped as follows: 1) 6 prepubertal boys with bone age 7 yr or less; 2) 5 prepubertal boys with bone age of more than 7 yr, 3) 10 boys in early puberty; 4) 9 boys with mid- to late puberty. Blood was obtained every 20 min from 2000-0800 h. An equal aliquot of each serum sample was pooled for determination of GH by bio- and immunoassays. The mean serum immunoreactive GH concentration increased from 2.1 +/- 0.3, 1.8 +/- 0.3, and 2.9 +/- 0.5 micrograms/L in groups 1, 2, and 3, respectively, to a peak of 4.6 +/- 0.7 micrograms/L in group 4 (P < 0.05 vs. groups 1-3). The mean serum GH bioactivity was 48 +/- 13 micrograms/L in group 1 and declined to 39 +/- 8 and 31 +/- 3 micrograms/L in groups 2 and 3, increasing to a maximum of 64 +/- 15 micrograms/L in group 4 (P < 0.05 vs. group 3). The ratio of bioactive to immunoreactive GH suggests that the biopotencies of secreted isoforms do not increase during pubertal maturation. The role of E2 in increasing GH secretion was characterized in 8 additional early pubertal boys. Each boy received a saline infusion from 1000-0800 h, followed 1 week later by an infusion of E2 at 4.6 nmol/m2.h. Blood was obtained every 15 min from 2200-0800 h for GH and LH and every 60 min for E2 and testosterone. An equal aliquot of each overnight serum sample was pooled for insulin-like growth factor I (IGF-I) and GH by immuno- and bioassays. The mean serum LH concentration decreased from 5.0 +/- 0.9 to 2.3 +/- 0.6 IU/L (P < 0.01), and the E2 concentration increased from 22 +/- 4 to 81 +/- 26 pmol/L (P < 0.01) during saline and E2 infusions, respectively. Mean serum GH concentrations as measured by immunoassay were similar during both infusions (6.6 +/- 1.4 vs. 9.7 +/- 2.1 micrograms/L; saline vs. E2 infusion, respectively). In contrast, the mean serum GH concentration, as measured by bioassay, decreased from 48 +/- 10 micrograms/L during saline infusion to 16 +/- 3 micrograms/L during E2 infusion (P < 0.05). The mean serum IGF-I concentration also decreased significantly from 116 +/- 17 to 93 +/- 15 micrograms/L (saline vs. E2 infusion, respectively; P < 0.05). Thus, although mean overnight serum GH concentrations increase in late puberty, whether measured by immuno- or bioassay, an acute increase in E2 produces an acute decline in serum GH bioactivity and a lesser decline in the serum IGF-I concentration. These unexpected changes indicate that E2 may affect pubertal growth and GH secretion in a complex or biphasic manner depending on the context in which it is administered.

Post-translational processing in the Golgi plays a critical role in the trafficking of the luteinizing hormone/human chorionic gonadotropin receptor to the cell surface

Point mutations in the luteinizing hormone/human chorionic gonadotropin (LH/hCG) receptor have been shown to cause constitutive activation which results in precocious puberty in affected males. We introduced one of these mutations, Asp-556 --> Gly, into the rat LH/hCG receptor and demonstrated that the mutant receptor constitutively activated adenylate cyclase in transfected 293 T cells. The cell surface expression of the mutant receptor was lower than that of the wild type receptor. Pulse-chase studies showed that the 73-kDa precursor of both the mutant and wild type receptors was synthesized at comparable efficiencies. However, post-translational processing of the mutant receptor to the mature 92-kDa form, which has N-linked complex type oligosaccharide chains, was impaired. Sensitivity of the mutant receptor to peptide-N-glycanase F and endoglycosidase H, and insensitivity to sialidase indicated that the 73-kDa species represents the high mannose form that has not yet been trafficked through the medial and trans Golgi. Additionally, although the wild type receptor was palmitoylated, the mutant receptor was not. Although the high mannose 73-kDa species is capable of binding LH/hCG, our results show that post-translational processing in the Golgi is required for the mature 92-kDa receptor to reach the cell surface.

Risky behavior and risk in adolescents with IDDM

PURPOSE

To determine: (1) the frequency of risky behaviors (alcohol and other drug use, smoking cigarettes, smokeless tobacco use, and unprotected intercourse); (2) the perception of general risks and diabetes-related risks from risky behaviors; (3) if perception of risk is related to engaging in risky behaviors; and (4) if perception of general risks and diabetes-related risks are influenced by age, gender, or race in adolescents with insulin dependent diabetes mellitus (IDDM). Decreasing risky behaviors in youth with IDDM is important because of their increased vulnerability to specific disease related physiologic and pathologic changes.

METHODS

A descriptive, cross-sectional design was used. Data on risky behavior and perception of risk were obtained by self-report during a regularly scheduled clinic visit. One hundred and fifty-five adolescents between ages of 10-20 years participated. Correlational and student's t-test analyses were used to test relationships and group differences (age, race, gender).

RESULTS

Thirty-nine percent of the sample reported alcohol use, 34% reported smoking cigarettes, 8% reported smokeless tobacco use, 10% reported drug use, and 29% reported unprotected intercourse. Perception of risk to peers from these behaviors was significantly higher (t = 8.1, df 153; p < .001) than risk to self. Females reported significantly lower (t = 3.08, df 52; p < .002) risk to self than males. There was no difference in perception of risk between youth who reported participating in risky behaviors (N = 38%) and those who did not (62%). Not surprisingly, the frequency of risky behavior increased with age (F = 15.46; p < .001).

CONCLUSIONS

Compared to community samples of middle school children, our sample had lower rates for most risky behaviors. As with community samples, the physical risks were known and perceived to be higher for peers than self. Perception of risk was not related to self-reports of risky behaviors. The lower rate of risky behaviors might reflect the success of educational efforts directed toward diabetes management or may be due to later initiation of behaviors, especially if personal social development is delayed. Additional research is indicated in order to understand the timing and trajectory of risky behavior and whether or not perception of risk deters youth with IDDM from engaging in risky behavior.

Comparison of the neuroendocrine control of pubertal maturation in girls and boys with spontaneous puberty and in hypogonadal girls

Puberty in boys is characterized by a nocturnal increase in mean LH concentration and LH pulse frequency. To determine whether similar mechanisms exist in girls, nocturnal serum LH concentrations were determined in 16 girls with constitutional delay of adolescence or idiopathic short stature who had or have subsequently been shown to have spontaneous puberty. Mean LH and LH pulse frequency and amplitude were analyzed in 3-h blocks and compared to those in 20 pubertal boys. Girls had an increase in mean LH concentration from 3.6 +/- 0.7 IU/L at 2000-2250 h to 4.8 +/- 0.9 IU/L at 0200-0450 h. LH pulse frequency increased from 0.27 +/- 0.11 pulses/girl.h at 2000-2250 h to 0.54 +/- 0.10 pulses/girl.h at 0200-0450 h. The increase in LH pulse amplitude, from 2.0 +/- 0.8 IU/L at 2000-2250 h to 4.1 +/- 1.1 IU/L at 2300-0150 h, did not achieve statistical significance because many girls had no pulses from 2000-2250 h. With advancing age, the day/night differences in LH concentration and LH pulse frequency disappeared in girls, but were preserved in boys of same pubertal stage. The effect of lack of estrogen on LH pulse characteristics was inferred by analyzing the LH profiles of 15 girls with gonadal dysgenesis who were age-matched to girls with spontaneous puberty. The girls with gonadal dysgenesis had an increase in mean LH concentration after 0200 h, but LH pulse frequency was rapid in all time blocks; the nocturnal increase in LH concentration was secondary to a significant increase in LH pulse amplitude. Older girls with gonadal dysgenesis had a loss of nighttime augmentation of LH secretion similar to that seen in girls with spontaneous puberty. These data suggest that the apparent slower LH pulse frequency encountered in girls with spontaneous puberty during waking hours may be related to estrogen suppression of LH pulse amplitude, which masks the true daytime LH pulse frequency. With or without pubertal estrogen exposure, developmental progression of LH secretion occurs more rapidly in girls than in boys. Thus, intrinsic sex differences exist in the timing and tempo of endocrine control of pubertal maturation between boys and girls.

Comparison of growth hormone and insulin-like growth factor-I regulation of estradiol and progesterone production in human luteinized granulosa cells

Growth hormone (GH) appears to affect the timing of puberty in children. The effects of GH on puberty may be related to direct GH action on ovarian function or may be mediated by IGF-I. To determine the likelihood that GH has direct effects on ovarian function, we compared the ability of GH and IGF-I to increase luteinized granulosa cell steroidogenesis in the absence and presence of gonadotropins. Cells were obtained from women undergoing in vitro fertilization for tubal disorders or male factor infertility and were placed in static culture. GH alone failed to alter progesterone or estradiol accumulation in the medium of cultured luteinized granulosa cells. IGF-I produced no increase in progesterone accumulation but increased estradiol accumulation 5.6-fold compared with cells treated with vehicle. The combination of GH and FSH produced an 0.83-fold increase in estradiol accumulation, whereas the combination of IGF-I and FSH resulted in a 2.9-fold increase in estradiol accumulation above FSH alone. Thus the direct effects of GH on granulosa cell steroid synthesis are modest compared with those of IGF-I. If GH has an effect on ovarian development at puberty, it is likely to be mediated by a GH-induced increase in circulating IGF-I.

Nocturnal naloxone fails to reverse the suppressive effects of testosterone infusion on luteinizing hormone secretion in pubertal boys

LH secretion is maximal during the night in pubertal boys, and testosterone (T) administration blunts this nocturnal rise of LH. We have previously shown that in pubertal boys, the acute negative feedback effects of T infusion on LH secretion during the daytime cannot be reversed by opioid receptor blockade. To determine whether the nocturnal secretion of LH in early puberty is regulated by endogenous opioid pathways, we determined whether naloxone during the night affected LH secretion or T-mediated suppression of LH secretion. Seven pubertal boys (bone age, 11-13.5 yr) were given a control infusion of saline, followed 1 week later by an infusion of T at 960 nmol/m2.h for 41 h starting at 2000 h. During both saline and T infusions, six iv boluses of saline were given hourly beginning at 2400 h on the first day, and six iv boluses of naloxone (0.1 mg/kg each) were given hourly beginning at 2400 h on the second day. Starting at 2200 h, blood was obtained every 15 min for LH and every 30 min for T determinations for 14 h each night. Pituitary responsiveness was assessed at the end of each study night by i.v. bolus administration of 250 ng/kg synthetic GnRH. T infusion increased the mean T concentration 6-fold (P < 0.0001) and suppressed the mean plasma LH concentrations from 5.6 +/- 0.6 to 3.8 +/- 0.6 IU/L (P < 0.01). The nocturnal augmentation of LH secretion was suppressed by the infusion of T, and this suppression was not reversed by naloxone. The mean nighttime plasma LH (2400-0600 h) was 8.1 +/- 1.1 IU/L during the control saline infusion and 5.1 +/- 0.6 IU/L during the T infusion (P < 0.01). The mean LH level was 4.0 +/- 0.7 IU/L during the administration of naloxone boluses concomitantly with the T infusion, not significantly different from that during the T infusion. Likewise, LH pulse frequency during the same time period was decreased by T infusion from 0.6 +/- 0.1 to 0.36 +/- 0.04 pulses/boy.h (P < 0.05), and it was unaltered by coadministration of naloxone (0.38 +/- 0.12 pulses/boy.h). Naloxone administration during the saline infusion did not increase either the mean plasma LH concentration (7.5 +/- 0.7 IU/L; P = NS vs. saline control) or the LH pulse frequency (0.69 +/- 0.1 pulses/boy.h; P = NS vs. saline control). Pituitary responsiveness to GnRH was similar on each of the 4 nights during either saline or T infusions.(ABSTRACT TRUNCATED AT 400 WORDS)

Vaccination with the immediate-early protein ICP47 of herpes simplex virus-type 1 (HSV-1) induces virus-specific lymphoproliferation, but fails to protect against lethal challenge

Assessing the immunobiological function of the individual proteins of herpes simplex virus-type 1 (HSV-1) continues to be important in elucidating virus-host interactions and for the rational design of subunit vaccines. In this report, the non-structural, immediate-early protein ICP47 of HSV-1 was examined for its ability to induce virus-specific immune responses. The ICP47 protein, when expressed from a recombinant vaccinia virus or when produced by cell-free, in vitro translation, induced a vigorous HSV-1-specific lymphoproliferative response. However, other common parameters of immunity such as neutralizing antibody, delayed-type hypersensitivity, and class I major histocompatibility complex (MHC)-restricted cytotoxic T lymphocytes (CTL) were not induced by ICP47. Moreover, mice immunized with vaccinia-expressed ICP47 were unable to survive lethal challenge with virulent HSV, indicating that in spite of its ability to induce significant HSV-1-specific lymphoproliferation, ICP47 appears unable to afford protective immunity in vivo. Possible reasons for this failure and the implications of these results in terms of vaccine design are discussed.

Growth hormone bioactivity in girls with Turner's syndrome: correlation with insulin-like growth factor I

We have recently developed a new bioassay for growth hormone (GH) in serum, which is based on the ability of GH to suppress glucose use in cultured murine adipocytes. We tested the hypothesis that bioactive GH (B-GH) concentrations would correlate better with the GH-dependent peptides, IGF-I, and IGF-binding protein-3 (IGFBP-3) than would GH determined by conventional RIA (RIA-GH). Twenty-five girls with Turner's syndrome were studied. The subjects had ages ranging from 4.8 to 15.9 y and height SD from the mean (SD score) ranging from -0.77 to -5.67. Blood samples were obtained every 15 or 20 min for 12 h overnight. For each girl, an equal aliquot of each overnight sample was pooled for determination of B-GH, RIA-GH, IGF-I, IGFBP-3, LH, FSH, and estradiol. Measurable estradiol concentrations were present in six girls and were sufficient to suppress gonadotropin concentrations in two girls, but they did not alter B-GH, RIA-GH, IGF-I, and IGFBP-3 concentrations compared with the age-matched girls without measurable estradiol concentrations. Hence, data for all girls were combined for subsequent regression analyses. RIA-GH did not correlate significantly with B-GH, IGF-I, or IGFBP-3. B-GH exhibited a significant correlation with IGF-I (r = 0.407, p < 0.05), and the correlation with IGFBP-3 was better than that for RIA-GH (r = 0.355 versus 0.064, B-GH and RIA-GH, respectively). None of the B-GH, RIA-GH, IGF-I, or IGFBP-3 concentrations had a significant correlation with height SD score or height velocity SD score.(ABSTRACT TRUNCATED AT 250 WORDS)

Bioactivity of human growth hormone in serum: validation of an in vitro bioassay

GH, in clinical practice, is determined by RIA, but RIA estimates may not accurately reflect serum GH bioactivity. The available measures of GH bioactivity lack either sensitivity, specificity, or a physiologically relevant end point. The objective of this research was to develop a physiologically relevant GH bioassay which would not only measure the bioactivity of purified GH preparations, but would also have sufficient sensitivity to measure GH bioactivity in human serum. The method consisted of incubating murine 3T3-F442A adipocytes in serum-free medium containing BSA, 14C-glucose, and increasing concentrations of GH or test materials for 24 h, followed by measurement of conversion of glucose to lipid. Interference by nonspecific serum factors was reduced by the addition of 10 micrograms/liter insulin, 25 nM dexamethasone, and 37 nM estradiol to the medium. In the presence of 10 micrograms/liter insulin, 50 micrograms/liter insulin-like growth factor-1 did not alter the ability of GH to suppress lipid accumulation. Epinephrine and glucagon could suppress lipid accumulation but only at concentrations greatly in excess of the physiological range in serum. Twenty two thousand dalton hGH produced dose-dependent suppression of lipid accumulation which was linear between 0.625 and 10 micrograms/liter (r = 0.926; P = 0.0001) with a half-maximal response of 3.0 +/- 0.2 micrograms/liter (n = six experiments). The intra- and interassay coefficients of variation were 7% and 19%, respectively. The assay was specific for GH since addition of human PRL produced suppression of lipid accumulation only at concentrations where contamination of the preparation by GH became a significant factor. ACTH also suppressed lipid accumulation but only at doses of 1000 micrograms/liter or greater. Human placental lactogen and hLH, hFSH, and hTSH did not cross-react with GH in this assay. Addition of human serum did not alter the slope of ED50 of the GH dose-response curve. Pools of serum from prepubertal and pubertal boys and girls, subjects treated with arginine or insulin, a diabetic girl, and a boy with gigantism who had a serum GH content of 80 micrograms/liter by RIA and 40 micrograms/liter by bioassay, produced dose response curves parallel to that of the GH standard curve. Serum from patients with hypopituitarism did not produce significant suppression of lipid accumulation in any assay. Recovery of 5 micrograms/liter GH added to human serum was 94%. Twenty thousand dalton GH also suppressed lipid accumulation in this assay, but was 2-fold less potent than 22,000 dalton GH.(ABSTRACT TRUNCATED AT 400 WORDS)

Luteinizing hormone pulse characteristics in early pubertal boys are the same whether measured by radioimmuno- or immunofluorometric assay

We tested the hypothesis that the improved sensitivity of immunofluorometric (IFMA) assays will lead to an increase in the number of detectable LH pulses compared to RIA in early pubertal boys, in whom LH secretion is low. To test this hypothesis we determined plasma LH concentrations in six pubertal boys (bone age, 12-16 yr) by IFMA and compared the results to RIA data reported previously. Each boy was given an infusion of saline, followed 1 week later by an infusion of testosterone (T; 960 nmol/h) for 33 h starting at 1000 h. Starting at 1200 h, blood was obtained every 15 min for LH determinations (RIA and IFMA) and every 30 min for T measurements. At the end of both studies, responses to GnRH (250 ng/kg) were assessed. The assay sensitivities for LH by RIA and IFMA (Delfia hLH Spec Pharmacia Diagnostics ENI, Columbia, MA) were 1.0 and 0.05 IU/L, respectively. LH pulses were identified by three independent pulse detection programs: Detect, Cluster, and Kushler-Brown. The correlation for LH values as measured by RIA and IFMA was highly significant (r = 0.81). There was a poor correlation between LH values determined by IFMA and RIA when LH values within 4 times the SD of each assay sensitivity were compared (r = 0.08; P = NS). T infusion suppressed LH pulse frequency by 40% and 66%, as determined by RIA and IFMA, respectively (P = NS). Using the Detect program, during the complete study in all 6 boys, 117 pulses of LH were identified by RIA and 93 by IFMA (79% ratio of detection IFMA/RIA). During saline infusion there were 73 vs. 69 LH pulses (94%), while during T infusion there were 24 vs. 44 LH pulses (55%), as detected by IFMA vs. RIA, respectively. Administration of naloxone did not accelerate LH pulse frequency during T infusion, as determined by either method. Changes in pituitary responses to exogenous GnRH also showed similar trends of augmentation by T infusion by both methods. We conclude that the use of IFMA does not lead to the anticipated increase in the detectability of LH pulsatility. Actually, fewer LH pulses were identified by IFMA in this group of boys. We speculate that this is due to the increased specificity of the IFMA assay. More significant was the finding that the physiological interpretation of the effects of T and naloxone on LH pulse frequency and responses to GnRH did not change whether LH was measured by RIA or IFMA.

Acute effects of testosterone infusion and naloxone on luteinizing hormone secretion in normal men

To evaluate the role of endogenous opioid pathways in the acute suppression of LH secretion by testosterone (T) infusion in men, we studied eight normal healthy volunteers who received a saline infusion, followed 1 week later by a T infusion (960 nmol/h) starting at 1000 h and lasting for 33 h. After 2 h of infusion (both saline and T), four iv boluses of saline were given hourly, and after 26 h of infusion, four hourly iv boluses of naloxone were given. Blood was obtained every 15 min for LH and every 30 min for T. T infusion increased the mean plasma T concentration 2.1-fold (18.7 +/- 2.1 to 39.5 +/- 3.5 nmol/L, saline vs. T infusion, P < 0.01). The mean plasma LH concentration was 7.9 +/- 0.5 IU/L during the saline control study and was decreased to 6.9 +/- 0.6 IU/L by the infusion of T (P < 0.05). LH pulse frequency was similar during both saline and T infusions (0.48 +/- 0.02 vs. 0.43 +/- 0.04 pulses/man.h, saline vs. T infusion). The mean LH pulse amplitude decreased from 4.3 +/- 0.4 IU/L during saline infusion to 3.3 +/- 0.2 IU/L during T infusion (P < 0.05). The administration of naloxone increased the mean plasma LH concentration significantly during saline infusion (7.6 +/- 0.4 to 10.0 +/- 0.9 IU/L, saline vs. naloxone boluses, P < 0.01), but not during T infusion (6.9 +/- 0.6 vs. 7.3 +/- 0.6 IU/L). LH pulse frequency increased significantly after the administration of naloxone during both saline and T infusions (0.54 +/- 0.04 to 0.71 +/- 0.08 pulses/man.h, saline vs. naloxone boluses during saline infusion, and 0.46 +/- 0.08 to 0.60 +/- 0.07 pulses/man.h during T infusion; P < 0.05). LH pulse amplitude was suppressed by T infusion, but administration of naloxone did not reverse this suppression. The mean amplitude of the LH response to exogenous GnRH (250 ng/kg) was decreased by T infusion from 48 +/- 13.5 to 31.2 +/- 8.5 IU/L (P < 0.01). Therefore, in men, the administration of naloxone increases LH pulse frequency during both saline and T infusions, but the acute suppression of LH pulse amplitude seen with T infusion was not reversed by naloxone. This pattern contrasts sharply with the effects of T infusion in pubertal boys, as elucidated by our earlier studies. The negative feedback effects of T on LH secretion are primarily hypothalamic in early pubertal boys and change to pituitary suppression in men.

Evaluation of gonadotropin responses to synthetic gonadotropin-releasing hormone in girls with idiopathic hypopituitarism

We hypothesized that prepubertal girls with gonadotropin deficiency would produce less follicle-stimulating hormone (FSH) in response to synthetic gonadotropin-releasing hormone (GnRH) than would gonadotropin-sufficient children. To test this hypothesis, we performed 103 GnRH tests serially in 21 children who had idiopathic hypopituitarism with growth hormone deficiency. We tried to predict whether puberty would occur in the 17 girls with bone ages of 8 years or less. Of these 17 girls, 4 failed to have spontaneous secondary sexual characteristics by age 16 1/2 years, and 12 had spontaneous complete pubertal development. One girl had incomplete pubertal maturation with partial gonadotropin deficiency; her results were combined with those of the girls who had no spontaneous pubertal development. With increasing bone age, the girls with complete pubertal development had a decrease in the increment of FSH released in response to GnRH, although basal gonadotropin concentrations did not change. For GnRH tests performed at bone ages of 8 years or less, basal luteinizing hormone (LH) values did not differ between girls with complete puberty and those with absent or incomplete puberty. However, basal FSH and the incremental response of LH and FSH to GnRH were greater in those with complete puberty. Only two girls with prepubertal bone ages at the time of testing, who subsequently had complete puberty, had incremental FSH responses to GnRH that were less than 5 IU/L. Individual incremental LH responses to GnRH did not discriminate well between groups. None of the girls with adrenocorticotropic hormone deficiency, either originally or subsequently, had spontaneous puberty, but 4 of 12 girls with thyrotropin deficiency, either originally or subsequently, had complete puberty. We conclude that a significant increase in GnRH-stimulated FSH suggests that spontaneous pubertal development will occur in girls with idiopathic hypopituitarism. However, a low FSH response to GnRH may not be diagnostic of gonadotropin deficiency.

MHC II-restricted, CD4+ cytotoxic T lymphocytes specific for herpes simplex virus-1: implications for the development of herpetic stromal keratitis in mice

Herpetic stromal keratitis (HSK) appears to represent an immunopathological reaction in which CD4+ T cells play a prominent role. However, the exact immunopathological mechanism(s) utilized by CD4+ T cells during HSK remains to be elucidated. In this study, the presence of cytotoxic CD4+ T lymphocytes in the cervical and retropharyngeal lymph nodes of Balb/c mice experiencing HSK was investigated. After in vitro depletion of CD4+ or CD8+ T cells with specific monoclonal antibodies and complement treatment, the cytotoxic functions of the remaining T cell populations were assayed by using target cells expressing either MHC Class I or both Class I and Class II. Our results showed the presence of a distinct cytotoxic T lymphocyte (CTL) population which was CD4+ and demonstrated lytic activity in a Class II-restricted fashion. Furthermore, these cells were able to develop into efficient effector CTL in the absence of CD8+ T lymphocytes as assessed by in vivo depletion experiments. Immunohistochemical methods were also utilized to show the presence of both CD4+ lymphocytes and I-A+ cells in the corneal tissues during HSK. These findings support the notion that direct lysis of infected Class II-bearing corneal cells by CD4+ CTL might be one of the mechanisms leading to stromal immunopathology in herpetic infections.

Naloxone does not reverse the suppressive effects of testosterone infusion on luteinizing hormone secretion in pubertal boys

In this study we wished to test whether, and if so when, the suppressive effects of testosterone on LH and, by inference, GnRH secretion are mediated via endogenous opioid pathways during male pubertal maturation. As a preliminary study, we evaluated the acute effects of a 24-h infusion of testosterone (T) in eight pubertal boys with constitutional delay of growth in order to determine the optimal time for administration of naloxone. Eight additional pubertal boys received a saline infusion, followed 1 week later by a similar T infusion starting at 1000 h and lasting for 33 h. After 2 h of infusion (both saline and T), four iv boluses of saline were given hourly, and after 26 h of infusion, four hourly iv boluses of naloxone were given. Blood was obtained every 15 min for LH and every 30 min for T measurements. T infusion increased the mean T concentration by 3.8-fold (P less than 0.001). Mean LH and LH pulse frequency were suppressed (P less than 0.01), and the sleep-associated increase in LH secretion was abolished. Naloxone administration during the infusion of T did not reverse the suppression of LH secretion. Compared to the saline control period, mean LH was significantly lower during T infusion during the time naloxone boluses were given (4.5 +/- 0.9 vs. 5.9 +/- 1.1 IU/L, T infusion and naloxone boluses vs. saline respectively, P less than 0.01). Although the suppression of LH pulse frequency remained significantly lower than that during the saline control period (0.23 +/- 0.04 pulses/boy.h during T infusion and saline boluses; 0.33 +/- 0.04 pulses/boy.h during T infusion plus naloxone boluses; 0.44 +/- 0.06 pulses/boy.h during saline infusion and saline boluses). Naloxone increased mean LH and LH pulse frequency only in the four older, more mature boys during the infusion of saline. Pituitary responsiveness to exogenous GnRH was not altered by infusion of T. We conclude that acute administration of T suppresses LH secretion and, by inference, GnRH secretion at all stages of pubertal maturation in boys. These negative feedback effects, however, cannot be reversed by coadministration of naloxone, even in mid- to late pubertal boys who respond to naloxone with increased pulsatile secretion of LH. These studies suggest that during pubertal maturation in boys, endogenous opioid pathways do not play a major role in the regulation of the negative feedback effects of T.

Differential regulation of serum immunoreactive luteinizing hormone and bioactive follicle-stimulating hormone by testosterone in early pubertal boys

The microheterogeneity and bioassayable activity of serum FSH (B-FSH) can be regulated by exogenous GnRH in boys with idiopathic hypogonadotropic hypogonadism and by estrogen in a women with gonadal dysgenesis, presumably via hormonally mediated changes in the degree of FSH glycosylation. To test the hypothesis that testosterone (T) regulates the circulating forms of B-FSH, we raised the serum T levels of early pubertal boys to adult levels. In this model, high dose T inhibits the pubertal nocturnal augmentation of LH secretion, apparently through decreased GnRH secretion. This model allowed us to test a second hypothesis, that B-FSH is a sensitive indicator of hypothalamic GnRH release. The boys were studied on two consecutive weekends, during which they received either saline (S) or T infusions. Beginning at noon on the study day, after an overnight acclimatization, the boys received either S or T at 33% or 100% of the adult male production rate. Blood was sampled from 2000-0800 at 10-min intervals for immunoactive LH and FSH (I-FSH) and for B-FSH, as determined by the in vitro Sertoli cell aromatase induction assay, and at 30-min intervals for T. Gonadotropin levels were analyzed as mean hourly or 3-h concentrations and as pulse profiles by two established objective peak detection programs, Cluster and Detect. During S treatment, mean LH increased after the onset of sleep (P = 0.0006) and, after plateauing for several hours, declined to baseline in the early morning hours. Mean levels of B-FSH were also minimally (but significantly) increased after the onset of sleep (P = 0.046) and paralleled the decline noted for LH. Mean levels of I-FSH did not demonstrate a diurnal rhythm. The effect of T was gonadotropin specific. High dose T abolished the nocturnal elevation in mean LH concentrations, but had no effect on the nocturnal elevation of B-FSH (P less than 0.05) or on I-FSH levels. The LH pulse frequency was greatest from 2300-0450 h, during S treatment (P = 0.016). The pulse frequency of B-FSH was also minimally increased after the onset of sleep (P = 0.045). The T infusion abolished the nocturnal increase in LH pulse frequency, without an effect on B-FSH pulse frequency. B-FSH pulse frequency exceeded LH pulse frequency during S treatment (8.0 +/- 0.7 pulses/12 h vs. 5.5 +/- 0.4), and B-FSH pulses persisted throughout the night. The pulse amplitudes of LH and B-FSH were not affected by T.(ABSTRACT TRUNCATED AT 400 WORDS)

Testosterone infusion reduces nocturnal luteinizing hormone pulse frequency in pubertal boys

Administration of testosterone (T) can inhibit LH secretion in early pubertal boys. However, the GnRH pulse generator is relatively resistant to the effects of T, since T infusion beginning at 2100 h, 3 h before the usual nighttime increase in T, does not suppress the characteristic increase in LH pulse frequency or amplitude associated with the onset of sleep in early pubertal boys. To test the hypothesis that the hypothalamic-pituitary axis must be exposed to T for a longer duration to suppress the nocturnal rise in LH pulse frequency and amplitude, we infused saline or T at one third the adult male production rate (320 nmol/h), beginning at 1200 h on two consecutive weekends in each of eight early to midpubertal boys. Blood was obtained from 2000-0800 h every 10 min for LH and every 30 min for T measurements. T infusion increased the mean plasma T concentration from 6.9 +/- 1.7 to 11.8 +/- 1.4 nmol/L (P less than 0.01) between 2000-0800 h. Despite the T infusion, the nocturnal rise in mean LH concentration and LH pulse frequency persisted, suggesting that the nocturnal amplification of LH, and by inference GnRH, secretion is resistant to the negative feedback effects of T. A higher dose of T, approximating the adult male production rate (960 nmol/h), was given to eight additional boys beginning at 1200 h. The mean T concentration increased from 4.2 +/- 1.7 to 20.8 +/- 3.1 (P less than 0.001) nmol/L between 2000-0800 h. The mean plasma LH concentration was suppressed by T infusion from 5.2 +/- 0.5 to 2.9 +/- 0.4 IU/L, and LH pulse frequency decreased from 0.50 +/- 0.04 to 0.27 +/- 0.11 pulses/boy/h (P less than 0.01). There was no nocturnal amplification of LH secretion, but high amplitude LH pulses did occur during the night in six of the eight boys. The low dose T infusion had no effect on pituitary LH release by exogenous GnRH. With the high dose T infusion, however, the ability of GnRH, at 25 ng/kg but not at 250 ng/kg, to release pituitary LH was amplified. Thus, T supplementation at one third the adult male production rate does not blunt the sleep-associated nighttime rise in LH pulse frequency or LH concentration. T infusion approximating the adult male production rate suppresses the nocturnal increase in LH pulse frequency and mean LH concentration, and high amplitude, slow frequency LH pulses similar to patterns seen in adult men persist.(ABSTRACT TRUNCATED AT 400 WORDS)

Nocturnal serum growth hormone concentration is not augmented by short-term testosterone infusion in pubertal boys

Chronic exposure to testosterone (T) increases growth hormone (GH) secretion. To determine whether acute exposure to T would also enhance GH secretion, we infused saline, followed 1 wk later by T, for 18-24 h at one-third the adult male production rate in 12 pubertal boys and at the adult male production rate in eight additional pubertal boys. Blood was obtained every 20 min for GH and every 30 min for T from 2000-0800 h. Though infusion significantly increased serum T concentrations in all 20 boys, mean GH concentration, GH pulse frequency, and GH pulse amplitude did not increase compared to the saline infusion night. The secretory dynamics of GH as a function of 3-h time blocks from 2000-0800 h were also determined in the eight boys who received the higher dose of T. The profile for mean GH concentration, pulse frequency, pulse amplitude, and peak area were not affected by acute infusion of T at concentrations sufficient to alter LH secretion. This suggests that, at least in pubertal boys, one must be exposed to T for a period longer than 12-18 h to induce increased GH secretion.

Bioactive follicle-stimulating hormone responses to intravenous gonadotropin-releasing hormone in boys with idiopathic hypogonadotropic hypogonadism

To test the hypothesis that exogenous pulsatile administration of GnRH will increase serum bioactive FSH (bFSH) levels, we studied four boys with suspected idiopathic hypogonadotropic hypogonadism (IHH). These boys presumably secreted relatively little GnRH. By virtue of their low baseline serum gonadotropin levels yet responsive pituitary gonadotrophs, these boys with IHH proved to be an excellent clinical model to test this hypothesis. Administration of GnRH (0.025 microgram/kg.dose) iv at 1- or 2-h intervals for 3-5 days resulted in an increase in serum bFSH after 91% of the GnRH doses. Serum immunoreactive FSH (iFSH) and LH (iLH) levels increased after 42% and 64% of the GnRH doses, respectively. Ninety percent of the iLH responses were concordant with bFSH responses, but only 33% of the iLH responses were concordant with iFSH responses. The serum bFSH responses occurred consistently within 20 min after GnRH administration and resulted in an increased serum bioactive to immunoreactive FSH ratio. By 60 min, serum bFSH levels had returned to preinjection levels. Serum testosterone and estradiol levels did not change during the period of GnRH administration in three of the four boys. We conclude that pulsatile, low dose iv GnRH administration in boys with IHH elicits significant serum bFSH increases by 20 min; the newly secreted FSH is preferentially enriched with increased in vitro FSH bioactivity, and it is rapidly cleared from serum (60 min). Therefore, serum bFSH measurements may provide a sensitive index of GnRH effects on the gonadotrophs.

Effects of human growth hormone on insulin-stimulated glucose metabolism in 3T3-F442A adipocytes

GH is believed to play a role in promoting insulin resistance in patients with diabetes and with GH excess. The means by which GH produces insulin resistance may be through direct suppression of glucose metabolism in target cells (insulin-independent) or by interfering with the ability of insulin to stimulate glucose metabolism (insulin-dependent). In 3T3-F442A adipocytes, long term incubation (24-72 h) with GH directly inhibits glucose oxidation and lipid synthesis in the absence of insulin. To distinguish the insulin-independent effects of GH on glucose metabolism from the insulin-dependent effects of GH, we examined the effect of GH on insulin-stimulated lipid accumulation in cultured 3T3-F442A adipocytes. Cells were incubated for 48-72 h with GH and then treated with insulin. Insulin stimulated lipid accumulation in GH-pretreated and control cells. Compared to control, GH-treated cells had lower absolute levels of lipid accumulation in the absence of insulin and at each insulin concentration tested. Thus, GH directly suppresses basal lipid accumulation and lowers the response to insulin. In addition, a 10 times higher insulin concentration was required to reach maximum stimulation of lipid accumulation in GH-treated cells (50 ng/ml) than in control cells (5 ng/ml). When cells were exposed simultaneously to insulin and GH for 72 h, GH treatment inhibited the ability of insulin to stimulate lipid accumulation, and the degree of suppression by GH was related to the GH concentration present. These observations suggest that GH suppresses glucose metabolism not only in the absence but also in the presence of insulin. Since short term (4-h) incubation with GH increases glucose metabolism transiently in GH-deficient preparations, we also examined the influence of short term incubation with GH on insulin responses. Cells were incubated for 4 h with varying concentrations of insulin in the simultaneous presence or absence of GH. Insulin stimulated the conversion of glucose to lipid when tested alone or in the presence of GH. Short term exposure to GH alone also stimulated glucose metabolism. The stimulation of lipid accumulation at insulin concentrations less than 5 ng/ml was greater with GH, but responses were comparable above 5 ng/ml insulin. The ability of insulin to bind to its receptor was not affected by prior treatment with GH for either short or prolonged time periods.(ABSTRACT TRUNCATED AT 400 WORDS)

Increased luteinizing hormone pulse frequency during sleep in early to midpubertal boys: effects of testosterone infusion

Gonadotropin secretion is pulsatile in prepubertal and early pubertal boys, and the onset of puberty is characterized by a sleep-associated rise in LH pulse amplitude. To determine whether an augmentation in LH pulse frequency as well as amplitude occurs at the onset of puberty, we studied gonadotropin secretion in 21 early to midpubertal boys. Blood samples were taken every 20 min (every 15 min in 4 boys) for LH determinations. A 2-fold increase in LH pulse frequency occurred during the nighttime sampling period (2200-0400 h) compared to that in the hours when the boys were awake (1000-2200 h). The maximum frequency (0.7 pulses/h) occurred between 2400 and 0200 h. The mean plasma LH concentration increased during the night from 2.3 +/- 0.2 (+/- SE) mIU/mL (2.3 +/- 0.2 IU/L) between 2000-2200 h to a maximum of 6.2 +/- 0.4 (6.2 +/- 0.4 IU/L) between 0200-0400 h. The mean plasma LH decreased to 5.5 +/- 0.4 mIU/mL (5.5 +/- 0.4 IU/L) between 0400-0600 h and to 4.2 +/- 0.5 (4.2 +/- 0.5 IU/L) between 0600-0800 h. Plasma testosterone rose during the night to a mean maximum value of 2.4 +/- 0.5 (+/- SE) ng/mL (8.3 +/- 1.7 nmol/L). This finding suggested that the rise in testosterone might play a role in decreasing LH secretion during the later hours of sleep (after 0400 h). To address this question and to study further the effects of testosterone in early puberty, we measured plasma LH concentrations every 10 min from 2000-0800 h in 8 early to mid-pubertal boys before and during short term testosterone administration. Saline or testosterone at a concentration of 9.33 micrograms/mL (32 mumol/L) was infused at a rate of 10 mL/h from 2100-1200 h to shift the nighttime testosterone rise 3 h earlier than would occur spontaneously. Blood samples were obtained every 10 min for LH and every 30 min for testosterone determinations from 2000-0800 h. Pituitary responsiveness was assessed by administering sequential doses of synthetic GnRH (25 and 250 ng/kg) at 1000 and 1200 h, respectively. The nighttime increase in LH pulse frequency and mean plasma LH concentration occurred between 2300 and 0200 h despite testosterone infusion. However, testosterone infusion was associated with significantly lower mean plasma LH concentrations from 0200-0800 h compared to those on the night of the saline infusion. Pituitary responsiveness to synthetic GnRH was unaltered by testosterone administration.(ABSTRACT TRUNCATED AT 400 WORDS)

Growth hormone promoted tyrosyl phosphorylation of growth hormone receptors in murine 3T3-F442A fibroblasts and adipocytes

Because many growth factor receptors are ligand-activated tyrosine protein kinases, the possibility that growth hormone (GH), a hormone implicated in human growth, promotes tyrosyl phosphorylation of its receptor was investigated. 125I-Labeled human GH was covalently cross-linked to receptors in intact 3T3-F442A fibroblasts, a cell line which differentiates into adipocytes in response to GH. The cross-linked cells were solubilized and passed over a column of phosphotyrosyl binding antibody immobilized on protein A-Sepharose. Immunoadsorbed proteins were eluted with a hapten (p-nitrophenyl phosphate) and analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and autoradiography. The eluate from the antibody column contained an Mr 134,000 125I-GH-receptor complex. A similar result was obtained when the adipocyte form of 3T3-F442A cells was used in place of the fibroblast form. O-Phosphotyrosine prevented 125I-GH-receptor complexes from binding to the antibody column, whereas O-phosphoserine and O-phosphothreonine did not. In studies of GH-promoted phosphorylation in 3T3-F442A fibroblasts labeled metabolically with [32P]Pi, GH was shown to stimulate formation of a 32P-labeled protein which bound to immobilized phosphotyrosyl binding antibodies. The molecular weight of 114,000 obtained for this protein is similar to that expected for non-cross-linked GH receptor. The Mr 114,000 phosphorylated protein could be immunoprecipitated with anti-GH antibody, indicating that GH remained noncovalently bound to this protein during absorption to and elution from the immobilized phosphotyrosyl binding antibody. Phosphoamino acid analysis after both limited acid hydrolysis and extensive base hydrolysis of the Mr 114,000 phosphoprotein confirmed the presence of phosphotyrosyl residues.(ABSTRACT TRUNCATED AT 250 WORDS)

Treatment of precocious puberty in the McCune-Albright syndrome with the aromatase inhibitor testolactone

The McCune-Albright syndrome is characterized by café au lait spots, fibrous dysplasia of bones, and sexual precocity. Girls with precocious puberty due to this syndrome have episodic increases in serum estrogen levels together with the formation of large ovarian cysts. The serum gonadotropin levels are typically suppressed, and the precocious puberty has not responded to treatment with long-acting analogues of luteinizing hormone-releasing hormone (LHRH). Encouraged by our initial success in a pilot study of one patient, we have now treated five girls with the McCune-Albright syndrome with the aromatase inhibitor testolactone, which blocks the synthesis of estrogens. Testolactone decreased the levels of circulating estradiol (P less than 0.05) and the ovarian volume (P less than 0.05), and there was a return to pretreatment levels after testolactone was stopped. During treatment, the peak responses of luteinizing hormone and follicle-stimulating hormone to stimulation by LHRH rose above suppressed pretreatment levels--significantly above pretreatment levels for follicle-stimulating hormone (P less than 0.02)--and then returned to pretreatment levels after testolactone was discontinued. Growth rates fell in three patients during treatment but could not be assessed in the other two because of bone deformities. The mean rate of bone maturation decreased and menses stopped in three of the four girls who were menstruating regularly. We conclude that testolactone is an effective treatment of precocious puberty in the McCune-Albright syndrome.

Ovarian function in girls with McCune-Albright syndrome

We measured plasma estradiol levels and ovarian volumes in eight girls with precocious puberty due to McCune-Albright syndrome. Six girls had gonadotropin-independent ovarian estrogen secretion and two girls had pubertal gonadotropin levels. Mean ovarian volume in all patients was significantly greater than in normal prepubertal girls. Mean ovarian volumes of the girls with McCune-Albright syndrome overlapped the range found in girls with idiopathic central precocious puberty or central precocious puberty associated with central nervous system lesions. However, the degree of asymmetry between the right and left ovaries was significantly greater in girls with McCune-Albright syndrome. Asymmetry was due, for the most part, to the presence of large solitary cysts in the larger of the two ovaries. In the six girls with McCune-Albright syndrome and gonadotropin-independent precocious puberty, both mean ovarian volume and the degree of asymmetry between the right and left ovaries were significantly correlated with plasma estradiol. Serum follicle-stimulating hormone bioactivity was increased in two patients but did not vary with ovarian cyst size. Thyroid-stimulating hormone levels were normal but serum prolactin was slightly elevated in one of the six girls with gonadotropin-independent precocious puberty. Fluctuation in the size of unilateral ovarian cysts appears to result in changes in the plasma estradiol level, leading to advancement and spontaneous regression of secondary sexual characteristics and menses in girls with McCune-Albright syndrome. The cause of the cyst formation is unknown but may be related to periodic elevation of as yet undefined serum factors such as follicle-stimulating hormone bioactive substances.

Limited dermal ossification: clinical features and natural history

For 9 years we have observed a girl who has ossification in the dermis with a strikingly limited distribution. Recently a second girl with similar dermal ossification restricted to a single extremity was identified. The ectopic bone is histologically identical to normal membranous bone. These two patients have no obvious underlying cause for soft tissue bone formation, and no disorder of calcium or phosphate metabolism. Ossification first involved the dermal and subcutaneous connective tissue, and with time advanced locally in the affected areas to bridge joints and limit mobility. The ossification has now extended to involve muscle fascia but has not involved the muscle itself. This disease appears to represent a heretofore unrecognized disorder of mesenchymal differentiation.

Glucocorticoid receptors in Epstein-Barr virus-transformed lymphocytes from patients with glucocorticoid resistance and a glucocorticoid-resistant New World primate species

Members of a previously reported family with glucocorticoid resistance and several New World primates have high plasma cortisol concentrations without any signs of glucocorticoid excess. The glucocorticoid receptor in circulating leukocytes and cultured skin fibroblasts from these patients and the animals is characterized by a decreased affinity for dexamethasone. On the other hand, the cell content of receptor is similar to that of corresponding tissues of normal humans. Detailed biochemical-biophysical studies of the glucocorticoid receptor in this familial syndrome and animal model became possible with the use of Epstein-Barr virus-transformed lymphocyte lines. Cell lines from patients with this syndrome and from the marmoset (Saguinus oedipus) contained decreased amounts of glucocorticoid receptors with concomitant decreases in nuclear receptor content compared to cultured Epstein-Barr virus-transformed lymphocytes from normal human subjects. This may reflect diminished induction of glucocorticoid receptor during viral transformation of cells from the patients and the animal model. Receptors from a severely affected glucocorticoid-resistant patient and the marmoset had decreased affinity for dexamethasone. Evidence for a mild affinity defect of the glucocorticoid receptor in a patient with asymptomatic glucocorticoid resistance was obtained by increased hormone-receptor dissociation at an elevated temperature. Thermal stability, mero-receptor formation, thermal activation of cytosolic receptor, and mol wt of receptors from all cell lines were normal. Only the receptors of the severely affected patient had a discernible defect in temperature-induced activation of intact cells. We conclude that the major detectable change in the receptor in both the patients and the animal model is the decreased affinity for glucocorticoid. Viral receptor induction is decreased in both patient and marmoset cells. The physiological relevance of this phenomenon is not known. Gross receptor molecule changes or changes in its stability at higher temperatures were not found. Mixing studies did not show involvement of cytosolic modifiers or inhibitors. Mutation(s) of the receptor molecule leading to low affinity for the hormone is the most likely explanation of the isolated glucocorticoid resistance in the patients. The glucocorticoid resistance of the New World primate, which is part of generalized steroid hormone resistance, appears to be a result of more complex changes.

Pituitary and recombinant deoxyribonucleic acid-derived human growth hormones alter glucose metabolism in 3T3 adipocytes

3T3-F442A adipocytes were used to compare the effects on glucose metabolism of pituitary human (h) GH and methionyl-hGH produced by recombinant DNA techniques (met-hGH 22K). Pituitary hGH and met-hGH 22K were similar in their ability to inhibit glucose oxidation and lipid accumulation after 48 h. After 4 h of incubation, both forms of hGH stimulated glucose oxidation transiently in 3T3 adipocytes. A bacterially produced form of the 20,000-dalton variant of hGH (met-hGH 20K) also stimulated glucose oxidation at 4 h and inhibited glucose oxidation and lipid synthesis after 48 h. All three forms of hGH had a similar ability to inhibit [125I]iodo-met-hGH 22K binding to 3T3-adipocytes. Thus, met-hGH 22K and 20K directly produce in 3T3 adipocytes the transient stimulation and delayed inhibition of glucose metabolism attributed to pituitary hGH, indicating that these metabolic effects are intrinsic to the hGH molecule.

Glucocorticoid receptors in Epstein-Barr virus-transformed human lymphocytes

Glucocorticoid receptors were studied in cultured human lymphocytes from normal donors after transformation with the Epstein-Barr Virus (EBV) and compared to those of circulating human mononuclear leukocytes. Both whole cell and cytosol fractions were examined for [3H]-dexamethasone binding. The concentration and absolute number of glucocorticoid binding sites were increased five-fold in the transformed cells when compared to the non-transformed human mononuclear leukocytes. However, the affinity (Kd) of the glucocorticoid receptor for dexamethasone was the same in both types of cells. The denatured glucocorticoid receptor, covalently labelled with [3H]-dexamethasone-21-mesylate, was identified by SDS polyacrylamide gel electrophoresis as a protein moiety with Mr approximately equal to 92,000, similar to that obtained from human non-transformed mononuclear leukocytes. The pattern of the activation of the hormone-receptor complexes, analyzed by phosphocellulose chromatography, was similar in both types of cells, and also the time-courses of loss of specific binding during thermal activation were similar. These results suggest that viral transformation is associated with increases in the concentration and the absolute number of glucocorticoid receptors whereas other qualitative receptor characteristics remain similar. Thus, transformation of cells with EB virus can provide a constant source of glucocorticoid receptors for study.

Growth hormone and insulin-like growth factors I and II produce distinct alterations in glucose metabolism in 3T3-F442A adipocytes

In 3T3-F442A adipocytes, human growth hormone (hGH) stimulates glucose oxidation in 4 hr. A maximal increase is evident at hGH concentrations of 50-100 ng/ml and rarely exceeds 50% above control. The stimulation is transient; after 48 hr of incubation with GH, glucose oxidation is significantly suppressed to 35% below control values. In view of the concept that insulin-like growth factors (IGF) may mediate the effects of GH, we compared the effects of hGH (500 ng/ml) and several preparations of IGF on glucose metabolism in 3T3 adipocytes. After 4 hr of incubation, IGF-I from human plasma stimulated glucose oxidation in a dose-related manner, producing a 10-fold increase at 50 ng/ml. Methionyl-IGF-I produced by recombinant DNA techniques was 85-88% as effective as IGF-I. IGF-II stimulated glucose oxidation 3-fold at 50 ng/ml after 4 hr of incubation. In contrast to the suppression observed with hGH after 48 hr, all three of the IGF preparations stimulated glucose oxidation after 48 hr of incubation and were as effective as they were after 4 hr. When each of the IGF preparations was tested (at 5 ng/ml) in combination with hGH, both the stimulatory and suppressive effects of GH were superimposed on the stimulation by the IGFs. Thus, the stimulatory properties of IGF differed from those of GH in that the maximum extent to which IGF increased glucose oxidation, compared with hGH, was as much as 20-fold greater. Furthermore, all of the IGF preparations stimulated glucose oxidation after 48 hr under conditions in which hGH suppressed glucose metabolism. Thus, it is unlikely that extracellular IGFs mediate the effects of hGH on glucose metabolism in 3T3-F442A adipocytes.

Testolactone treatment of precocious puberty in McCune-Albright syndrome

Current medical and surgical therapies of precocious puberty in McCune-Albright syndrome are often unsatisfactory. We used an aromatase inhibitor, testolactone, to treat precocious puberty in a girl with McCune-Albright syndrome. This child was unresponsive to 28 weeks of treatment with the long-acting agonist of LRH, D-trp6-pro9-NEt-LRH. During testolactone therapy, menses ceased, bone age advancement and height velocity diminished, and plasma oestradiol levels were suppressed. Serum gonadotrophin levels remained in the prepubertal range. Testolactone may be an effective therapy of precocious puberty in girls with McCune-Albright syndrome.

Limited proteolysis of covalently labeled glucocorticoid receptors as a probe of receptor structure

[3H]Dexamethasone 21-mesylate affinity-labeled glucocorticoid receptors were subjected to controlled proteolysis by trypsin, chymotrypsin, and Staphylococcus aureus V8 protease and then analyzed on denaturing constant percentage or gradient polyacrylamide gels. The molecular weights (Mr congruent to 98 000) and cleavage patterns for rat liver and HTC cell receptors indicated extensive homology between the glucocorticoid receptors from normal rat liver and a transformed rat liver cell line. The major DNA-binding species generated by chymotrypsin treatment was found to be a 42K fragment that was accompanied by several unresolved, slightly lower molecular weight fragments. The meroreceptors obtained after trypsinization were comprised of two species of Mr 30 000 and 28 000. Each of the three proteases, despite their differing specificities, generated fragments with molecular weights close to 42 500, 30 500, and 27 000. Nevertheless, each of the three proteases gave rise to a distinctive "ladder" of labeled fragments. No differences could be detected in the digestion patterns of unactivated and activated HTC cell complexes for all three proteases. Also, native and denatured receptor-steroid complexes yielded surprisingly similar digestion patterns with each enzyme. Digestion of denatured complexes readily generated large amounts of a fragment of Mr congruent to 15 000 that was much smaller than the protease-resistant meroreceptors formed from native complexes. The presence of these approximately 15K fragments suggested that the [3H]dexamethasone 21-mesylate labeling of the steroid-binding cavity is restricted to a relatively small segment of the receptor.

Variable response to a long-acting agonist of luteinizing hormone-releasing hormone in girls with McCune-Albright syndrome

Six girls with McCune-Albright syndrome were treated for at least 2 months with the long-acting LHRH agonist D-Trp6-Pro9-NEt-LHRH, which previously was found to be an effective treatment for true precocious puberty. Nocturnal and LHRH-stimulated serum gonadotropin levels and plasma estradiol levels were measured before treatment and after 2-3 months of treatment. Five of the six girls had no decrease in serum gonadotropin or plasma estradiol levels during therapy, and their pubertal signs were unaffected by treatment. All five of these girls had serum gonadotropin levels that were within or below the normal prepubertal range. The sixth girl, who had gonadotropin levels in the normal pubertal range before treatment, had decreased serum gonadotropin and plasma estradiol levels during 1 yr of LHRH analog therapy. This was associated with cessation of menses and regression of secondary sexual changes. The failure of LHRH analog to modify the course of precocious puberty in the five patients with prepubertal serum gonadotropin concentrations is further evidence that the mechanism of precocious puberty in most girls with McCune-Albright syndrome differs from that in patients with true precocious puberty.

Absence of pubertal gonadotropin secretion in girls with McCune-Albright syndrome

Precocious puberty in girls with McCune-Albright syndrome has been attributed in some cases to early activation of the hypothalamic-pituitary-gonadal axis and in other cases to sex steroid secretion by apparently autonomous ovarian cysts. We evaluated serum gonadotropins and sex steroids in six girls (aged 1-9 yr) with McCune-Albright syndrome. The children had Tanner stage II-IV pubertal development. In five patients, nocturnal gonadotropin concentrations and the gonadotropin response to LHRH were within the normal range for prepubertal children. Thus, the precocious puberty in these patients could not be explained by activation of the hypothalamic-pituitary-ovarian axis. One child had high amplitude nocturnal pulses of serum LH and a LH-predominant response to LHRH. She was the oldest of the six girls and had a bone age of 13.5 yr which is within the range in which hypothalamic-pituitary-ovarian activation normally occurs. The children all had ovarian enlargement and ovarian cysts determined by ultrasound. It appears that precocious puberty in McCune-Albright syndrome may result from ovarian estrogen secretion in the absence of normal pubertal activation of the hypothalamic-pituitary-ovarian axis.

Covalent labeling of rat thymocyte and human lymphoid glucocorticoid receptor

Lymphoid cells contain specific receptors for glucocorticoids. We have used [3H]dexamethasone-21-mesylate to label covalently glucocorticoid receptors in rat thymic lymphocytes and in neoplastic cells obtained from patients with acute lymphoblastic leukemia and malignant lymphoma. The covalently labeled glucocorticoid receptors were identified by polyacrylamide gel electrophoresis (in the presence of 0.1% sodium dodecyl sulfate). In cytosolic fractions prepared from rat thymic lymphocytes, [3H]-dexamethasone-21-mesylate labels a protein (Mr approximately equal to 95,000) which was identified as the glucocorticoid receptor by the following criteria: (a) labeling of this moiety is inhibited by treatment with a 100-fold molar excess of glucocorticoids, such as dexamethasone and triamcinolone acetonide; and (b) the covalently labeled Mr approximately equal to 95,000 protein is activated (by heating at 20 degrees for 30 min) to a form that binds to DNA-cellulose. When intact thymocytes are treated with [3H]dexamethasone-21-mesylate, an Mr approximately equal to 95,000 moiety is also labeled covalently. Approximately 35% of the glucocorticoid receptors can be labeled covalently when intact thymocytes are treated with 100 nM [3H]dexamethasone-21-mesylate for 30 min at 4 degrees. Neoplastic cells from acute lymphoblastic leukemia and malignant lymphoma were treated with [3H]dexamethasone-21-mesylate. In all samples, an Mr approximately equal to 95,000 moiety was labeled covalently; labeling was inhibited by excess glucocorticoid. Smaller moieties were also identified by competition experiments; these may represent proteolytic fragments of the Mr approximately equal to 95,000 receptor. Thus, in rat and human lymphoid cells, [3H]dexamethasone-21-mesylate can be used to label covalently the glucocorticoid receptor.

Postpartum cytomegalovirus infection. A hazard of multiple transfusions

A patient whose postpartum course included the defibrination syndrome and Bacteroides septicemia developed recurrent high fever. Cytomegalovirus infection was suspected on the basis of the clinical features and a history of massive blood transfusion, and was confirmed by subsequent observations. Recognition of this disease and its typically benign course averts the need for extensive diagnostic procedures, exploration, and empiric drug therapy trials.