Smoking is a risk factor for pulmonary metastasis in colorectal cancer.

AIM: The hepatic microenvironment, which may include chronic inflammation and fibrosis, is considered to contribute to the pathogenesis of liver metastases of colorectal cancer. A similar mechanism is anticipated for pulmonary metastases, although no reports are available. Smoking causes pulmonary inflammation and fibrosis. Thus, we hypothesized that smokers would be especially affected by pulmonary metastases of colorectal cancer. In this study, we attempted to clarify the impact of smoking on pulmonary metastasis of colorectal cancer. METHOD: Between September 2005 and December 2010 we reviewed 567 patients with pathological Stage I, II or III colorectal cancer, whose clinicopathological background included a preoperative smoking history, pack-year history from medical records. Univariate and multivariate analyses using the Cox proportional hazard model were performed to determine the independent prognostic factors for pulmonary metastasis-free survival. RESULTS: Pulmonary metastases occurred in 39 (6.9%) patients. The smoking histories revealed 355 never smokers, 119 former smokers and 93 current smokers among the subjects. Multivariate analysis revealed that being a current smoker (hazard ratio = 2.72, 95% CI 1.18-6.25; P = 0.02) was an independent risk factor for pulmonary metastases. CONCLUSION: Smoking may be a risk factor for pulmonary metastasis of colorectal cancer. Cessation of smoking should be recommended to prevent pulmonary metastasis, although further basic and clinical studies are required.

Transgenic mice overproducing human thioredoxin-1, an antioxidative and anti-apoptotic protein, prevents diabetic embryopathy.

AIMS/HYPOTHESIS: Experimental studies have suggested that apoptosis is involved in diabetic embryopathy through oxidative stress. However, the precise mechanism of diabetic embryopathy is not yet clear. Thioredoxin (TRX) is a small, ubiquitous, multifunctional protein, which has recently been shown to protect cells from oxidative stress and apoptosis. Using transgenic mice that overproduce human TRX-1 (TRX-Tg mice), we examined whether oxidative stress is involved in fetal dysmorphogenesis in diabetic pregnancies. METHODS: Non-diabetic and streptozotocin-induced diabetic (DM) female mice were mated with male TRX-Tg mice. Pregnant mice were killed either at day 10 or day 17 of gestation, and viable fetuses and their placentas were recovered, weighed and assessed for gross and histological morphology, biochemical markers and gene expression. RESULTS: In both wild-type (WT) and transgenic (Tg) groups, fetal and placental weights in the diabetic group were significantly decreased compared with the non-diabetic group. The incidence of malformation was higher in the diabetic group, and was significantly decreased in the TRX-Tg group (DM-WT vs DM-Tg; 28.6% vs 10.4%). Oxidative stress markers such as thiobarbituric acid reactive substances and 8-hydroxy-2'-deoxyguanosine were increased in DM-WT group fetuses but were decreased in fetuses from the DM-Tg group. Furthermore, immunohistochemically assayed apoptosis and cleaved caspase-3 production in embryonic neuroepithelial cells was significantly increased in the DM-WT group, and was significantly decreased in the DM-Tg group. CONCLUSIONS/INTERPRETATION: These results indicate that oxidative stress is involved in diabetic embryopathy, and that the antioxidative protein TRX at least partially prevents diabetic embryopathy via suppression of apoptosis.

A novel retinoid X receptor-independent thyroid hormone response element is present in the human type 1 deiodinase gene.

We identified two thyroid hormone response elements (TREs) in the 2.5-kb, 5'-flanking region of the human gene encoding type 1 iodothyronine deiodinase (hdio1), an enzyme which catalyses the activation of thyroxine to 3,5,3'-triiodothyronine (T3). Both TREs contribute equally to T3 induction of the homologous promoter in transient expression assays. The proximal TRE (TRE1), which is located at bp -100, has an unusual structure, a direct repeat of the octamer YYRGGTCA hexamer that is spaced by 10 bp. The pyrimidines in the -2 position relative to the core hexamer are both essential to function. In vitro binding studies of TRE1 showed no heterodimer formation with retinoid X receptor (RXR) beta or JEG nuclear extracts (containing RXR alpha) and bacterially expressed chicken T3 receptor alpha 1 (TR alpha) can occupy both half-sites although the 3' half-site is dominant. T3 causes dissociation of TR alpha from the 5' half-site but increases binding to the 3' half-site. Binding of a second TR to TRE1 is minimally cooperative; however, no cooperativity was noted for a functional mutant in which the half-sites are separated by 15 bp, implying that TRs bind as independent monomers. Nonetheless, T3 still causes TR dissociation from the DR+15, indicating that dissociation occurs independently of TR-TR contact and that rebinding of a T3-TR complex to the 3' half-site occurs because of its slightly higher affinity. A distal TRE (TRE2) is found at bp -700 and is a direct repeat of a PuGGTCA hexamer spaced by 4 bp. It has typical TR homodimer and TR-RXR heterodimer binding properties. The TRE1 of hdio1 is the first example of a naturally occurring TRE consisting of two relatively independent octamer sequences which do not require the RXR family of proteins for function.

Clinical features of ovarian cancer in Japanese women with germ-line mutations of BRCA1.

We analyzed the clinical features of 25 ovarian cancer patients who were associated with germ-line mutations of BRCA1 from four site-specific ovarian cancer families and seven breast-ovarian cancer families in Japan. The average age at diagnosis was 51.1 years (range, 38-77 years). Histological examination revealed 24 serous cyst adenocarcinomas in 25 patients. In 23 patients with clear clinical records, 3 patients had stage I disease, 17 had stage III disease, and 3 had stage IV disease. Thirteen patients with stage III disease who were treated with cisplatin-containing chemotherapy following tumor reduction surgery showed more favorable outcomes in both the survival rate and disease-free intervals, compared with age- and treatment course-matched controls (5-year survival rate, 0.786 versus 0.303; median disease-free interval, 91.43 versus 40.92 months; P < 0.05 for both, by logarithmic rank test). Our statistical model for the inheritance of susceptibility to ovarian cancer was derived from the analysis of 26 patients and 19 healthy carriers of 12 families. The expected lifetime risk of ovarian cancer is about 80% for women with mutations of BRCA1. These results suggest that the clinical outcome of ovarian cancer with germ-line mutations of BRCA1 appears to be more favorable than that with sporadic cases and that the disease penetrance among pedigrees with germ-line mutations of the BRCA1 gene is substantially high.

Insulin binding, glucose oxidation, and methylglucose transport in isolated adipocytes from pregnant rats near term.

To elucidate the mechanism of insulin resistance during late pregnancy, we studied [125I]iodoinsulin binding, [1-14C]glucose oxidation, and 3-O-[methyl-14C]glucose transport in adipocytes isolated from pregnant rats on day 19 or 20 of gestation. Neither the affinity or number of insulin receptors on pregnant rat adipocytes differed from those on age-matched nonpregnant female rats. Insulin-stimulated glucose oxidation was reduced in the pregnant rat adipocytes. The maximum velocity of insulin-stimulated methylglucose transport was also significantly reduced in the pregnant rat adipocytes. These results suggest that insulin resistance in isolated adipocytes from pregnant rats near term is caused by some postreceptor changes, one of which is a reduction in the number and/or mobility of insulin-stimulated hexose transporters.

Structure-activity relationships for thyroid hormone deiodination by mammalian type I iodothyronine deiodinases.

The bioactivity of thyroid hormone is determined to a large extent by the monodeiodination of the prohormone T4 by the hepatic selenoenzyme type I iodothyronine deiodinase (IDI), i.e. by outer ring deiodination (ORD) to the active hormone T3' or by inner ring deiodination (IRD) to the inactive metabolite rT3. IDI also catalyzes the IRD of T3 and the ORD of rT3' both to T2, as well as the deiodination of different iodothyronine sulfates, e.g. IRD of T3S and ORD of T2S. Previous studies have indicated important differences in catalytic specificity between dog IDI (dID1) and human ID1 (hID1), in particular with respect to the ORD of rT3. This study was done to investigate the relationship between structure and catalytic function of this enzyme by comparing the deiodination of T4, T3, rT3, T3S, and T2S by native dID1 and hID1 in liver microsomes as well as by recombinant wild-type, chimeric and mutated d/hID1 enzymes expressed in HEK293 cells. With both native and recombinant wild-type enzymes, the substrate specificity was T3S > T2S approximately rT3 approximately T4 > T3 for dID1, and rT3 > > T2S approximately T3S > T4 approximately T3 for hID1. Whereas ORD of T4 and of T4, T3, and T3S showed relatively little variation between the different d/hID1 constructs, large differences were found for the ORD of rT3 and T2S. Both reactions were favored by the presence of the amino acids G, E and, in particular, F, present in hID1 at positions 45, 46, and 65, instead of the dID1 residues N, G, and L, respectively. However, although ORD of rT3 was not affected by the presence (hID1) or absence (dID1) of the TGMTR(48-52) sequence, the ORD of T2S was markedly inhibited by the presence of this sequence. Therefore, we have identified structural elements in ID1 that have substrate-specific impacts on deiodination. Our results suggest the specific interaction of the mono-substituted inner ring of the substrates rT3 and T2S but not the disubstituted inner ring of T3, T3S, or T4, with the aromatic ring of F65 in Id1, perhaps by pi-pi interactions.

Iodothyronine 5'-deiodinase activity in cultured rat myocardial cells: characteristics and effects of triiodothyronine and angiotensin II.

Using a primary culture of neonatal rat heart, we investigated the properties of iodothyronine 5'-deiodinating activity in the heart. 125I- release from [125I] reverse T3 incubated with cell homogenates depended on the concentrations of protein and dithiothreitol, pH, incubation time, and temperature of the incubation mixture. The activity was almost completely inhibited by 10(-3)-10(-5) M propylthiouracil and had the higher affinity for reverse T3 than T4. These findings indicate that type I iodothyronine 5'-deiodinase(I-5'-D) exists in cultured neonatal rat myocardial cells. Then, we studied the direct effects of T3, insulin, glucocorticoid, and angiotensin II (AII) on myocardial I-5'-D. The addition of 10(-9)-10(-7) M T3 or 10(-9)-10(-6) M AII to the culture medium increased I-5'-D activity in a dose-dependent manner. Insulin and dexamethasone, however, had no significant effects. Kinetic studies revealed that maximum velocities in T3- and AII-treated cells were 2.1- and 1.8-fold above the control value, respectively, whereas the apparent Michaelis-Menten constant did not alter significantly both in T3- and AII-treated cells. Moreover, the treatment of cyclohexamide combined with T3 or AII completely abolished the stimulating effect of these agents on I-5'-D activity. From these data, it is suggested that both T3 and AII increase the activity of myocardial I-5'-D by their direct actions to the heart, probably through the new synthesis of I-5'-D.

Stimulation of rat atrial natriuretic peptide (rANP) synthesis by triiodothyronine and thyroxine (T4): T4 as a prohormone in synthesizing rANP.

Thyroid hormones have been reported to increase the secretion and synthesis of atrial natriuretic peptide (ANP) in vitro. In this study, we focused on the role of type I T4 5'-deiodinase to investigate the stimulating effects of T4 on ANP synthesis and secretion by measuring cellular content and secretion into the medium of immunoreactive rat ANP (IR-rANP) and rANP mRNA levels in cultured rat neonatal atrial myocytes. Both T3 (10(-9)-10(-7) M) and T4 (10(-8)-10(-6) M) increased cellular content and secretion into the medium of IR-rANP in a dose-dependent manner. However, these effects of T4 were completely inhibited by the addition of propylthiouracil, which selectively suppressed type I T4 5'-deiodinase activity. Methimazole, which did not alter T4 5'-deiodinase activity, had no effects on T4-induced IR-rANP increase. In the measurements of rANP mRNA levels by dot blot analysis, T3 (10(-8) and 10(-7) M) and T4 (10(-7) and 10(-6) M) increased rANP mRNA levels in the same way as they increased IR-rANP content. Although T4-increased rANP mRNA levels were also inhibited by propylthiouracil, methimazole did not alter the effect of T4. Moreover, T4-induced rANP mRNA accumulation in atrial myocytes was further stimulated by the addition of dithiothreitol, suggesting that the deiodinating activity was thiol sensitive. These data suggest that the stimulating effect of T4 on cellular IR-rANP content and rANP mRNA levels is entirely induced after it is converted to T3 by type I T4 5'-deiodinase in atrial myocytes and that T4 serves as a prohormone for T3 in synthesizing rANP.

Synergistic effect of thyroid hormone and thyrotropin on iodothyronine 5'-deiodinase in FRTL-5 rat thyroid cells.

The effects of T3 and T4 on the iodothyronine 5'-deiodinase (5'-D) activity in FRTL-5 rat thyroid cells were investigated. T3 and T4 stimulated the 5'-D activity in a dose-dependent manner. Kinetic studies showed that the stimulation of the 5'-D by T3 was associated with an increase in maximum velocity (Vmax) in [11.9 +/- 0.2 (mean +/- SE) and 25.4 +/- 0.9 pmol I-released/mg protein.min, respectively, in control and cultured with 10(-9) M T3 for four days] but without a change in apparent Michaelis-Menten constant (Km) (94.8 +/- 5.3 nM and 105.4 +/- 12.1 nM, respectively). Furthermore, cycloheximide (5 microM) completely abolished the stimulatory effect of T3 on the 5'-D activity. T3 and T4 also enhanced the 5'-D activity stimulated by TSH in a dose-dependent manner. Kinetic studies showed that the stimulatory effect of T3 on the 5'-D stimulated by TSH was again associated with an increase in Vmax (86.0 +/- 4.0 and 166.5 +/- 1.9 pmol I- released/mg protein.min, respectively, cultured with 0.3 U/liter TSH and cultured with TSH plus 10(-9) M T3 for four days) without a change in apparent Km (114.0 +/- 7.4 nM and 111.6 +/- 12.5 nM, respectively). Cycloheximide (5 microM) completely abolished the stimulatory effect of TSH plus T3 on the 5'-D activity. There were no significant differences observed between cells cultured with TSH and with TSH plus T3 in either the intra- or extracellular cAMP contents. Furthermore, T3 enhanced the 5'-D activity stimulated by (Bu)2 cAMP. These results strongly suggest that T3 or T4 was synergistic with TSH in stimulating the 5'-D activity in FRTL-5 cells, and that cAMP production would be an important component of the synergism.

Thyrotropin and triiodothyronine regulate iodothyronine 5'-deiodinase messenger ribonucleic acid levels in FRTL-5 rat thyroid cells.

We investigated the regulation of type I iodothyronine 5'-deiodinase (5'-D) gene expression by TSH and T3 in FRTL-5 rat thyroid cells. Northern blot analysis revealed that these cells express a 5'-D messenger RNA (mRNA) species of 2.1 kilobases. Readdition of TSH to FRTL-5 cells, precultured in both thyroid hormones and TSH-depleted medium for 4 days, increased 5'-D mRNA levels, reaching a maximum (2.8-fold compared to control) after 12 h of TSH (10 microU/ml) stimulation. Dibutyryl cAMP (DBC) and forskolin mimicked this stimulatory effect of TSH on 5'-D mRNA levels. T3 also increased the 5'-D mRNA levels, reaching a maximum (2-fold compared to control) after 8 h of T3 (10(-9) M) stimulation. Addition of TSH (10 microU/ml) or DBC (1 mM) together with T3 (10(-9) M) further increased 5'-D mRNA levels, reaching a maximum (5-fold compared to control) after 12 h of stimulation. Examination of the rate of disappearance of 5'-D mRNA levels after inhibition of mRNA transcription by actinomycin-D revealed that neither TSH nor T3 significantly affected the rate of disappearance. Cycloheximide, a protein synthesis inhibitor, almost completely blocked the induction of 5'-D mRNA by TSH and DBC, but did not block the induction by T3. These results suggest that both TSH and T3 increase 5'-D mRNA levels probably by increasing transcription rate, and that TSH regulates it, in part via the second messenger cAMP, for which cycloheximide-sensitive de novo protein synthesis is required, whereas T3 does without requiring it.

The structure of the coding and 5'-flanking region of the type 1 iodothyronine deiodinase (dio1) gene is normal in a patient with suspected congenital dio1 deficiency.

We analyzed the exon-intron structure of the human type 1 deiodinase gene (dio1) and compared it with that of a patient with suspected congenital type 1 deiodinase (D1) deficiency. The hdio1 gene is identical in exon-intron arrangement to the mouse gene, with coding sequences and a selenocysteine insertion sequence (SECIS) element contained in four exons. There were no mutations in the sequences of exons 1-4 of the patient's genomic DNA. Functional studies by transient expression techniques showed no difference in basal promoter activity or T3 responsiveness between the patient's and the normal dio1 gene. A structural abnormality in the dio1 gene is not a likely explanation for this patient's D1-deficient phenotype.

3,3',5'-Triiodothyronine inhibits collagen-induced human platelet aggregation.

To clarify further the activity of rT3, we examined the effect of rT3 on collagen-induced platelet activation as reflected by aggregation, serotonin release, and protein phosphorylation. rT3, T4, T3, and triiodothyroacetic acid inhibited collagen-induced platelet aggregation and serotonin release from platelets in a dose-dependent manner. However, thyronine did not inhibit collagen-induced platelet aggregation. The concentration at which rT3 inhibited by 50% collagen-induced platelet aggregation was 30 +/- 4 (mean +/- SE) mumol/L. rT3, T4, and T3 did not differ significantly in their abilities to inhibit platelet aggregation. Moreover, rT3 inhibited collagen-induced phosphorylation of the 20-kilodalton protein (myosin light chain) in platelets. In contrast, rT3 did not inhibit 12-O-tetradecanoylphorbol 13-acetate (TPA)- or thrombin-induced platelet aggregation and inhibited only minimally TPA-induced 40-kilodalton protein phosphorylation. These results suggest that rT3 inhibits collagen-induced platelet activation by inhibiting the activity of myosin light chain kinase and that it may be interesting to investigate some kinds of activity of rT3.

Identification of a 27-kilodalton protein with the properties of type I iodothyronine 5'-deiodinase in human thyroid gland.

N-Bromoacetyl-[125I]T4(BrAc[125I]T4) was used as affinity label to identify type I 5'-deiodinase (5'-D) in human thyroid glands. Affinity labeled proteins were analyzed by autoradiography after sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Human thyroid microsomes labeled with BrAc[125I]T4 showed the most prominent radiolabeled band of protein at a mol wt of approximately 27,000 (p27). BrAc[125I]T4 incorporations into p27 were significantly higher in both Graves' and follicular adenomas than in normal thyroids. On the other hand, four cases out of five carcinomas were lower than the least value of normal thyroids. Furthermore, an excellent correlation was observed between 5'-D activities and quantities of p27 in all cases (r = 0.96; P less than 0.001). Labeling of p27 was strongly inhibited by preferred type I 5'-D substrate rT3, but to a lesser extent by poor substrate T4 or T3, and the type I 5'-D inhibitor, propylthiouracil and iopanoic acid, also inhibited the p27 labeling in normal and various diseases. In addition, the rate of enzyme inactivation by BrAcT4 equaled the rate of p27 labeling. These data suggest that p27 may be a type I 5'-D itself or at These data suggest that p27 may be a type I 5'-D itself or at least the substrate-binding subunit of this enzyme in human thyroid, and that both Graves' and follicular adenoma thyroids contain larger amounts of it, and papillary adenocarcinoma thyroids smaller than normal amounts.

Graves' immunoglobulin G stimulates iodothyronine 5'-deiodinating activity in FRTL-5 rat thyroid cells.

To elucidate the effect of Graves' immunoglobulin G (IgG) on iodothyronine deiodination in the thyroid, we examined the characteristics of iodothyronine 5'-deiodinating (I-5'-D) activity in FRTL-5 rat thyroid cells and the effect of Graves' IgG on its activity. FRTL-5 cells were sonicated and incubated with 0.5 mumol/L rT3 with a tracer amount of [125I]rT3 in 0.1 mol/L phosphate buffer containing 1 mmol/L EDTA and 0.5 mmol/L dithiothreitol. The released 125I- was separated by Dowex-50WX2 column and counted. The amount of I- released was tissue, incubation time, temperature, and pH dependent, strongly suggesting that the reaction is enzymatic. The activity was completely inhibited by propylthiouracil. The Km value for rT3 was approximately 0.32 microM when analyzed by Lineweaver-Burk plot. TSH, dibutyl cAMP, and Graves' IgG induced I-5'-D activity in a dose-dependent manner. However, cycloheximide (5 mumol/L) abolished the stimulating effects of these agents on I-5'-D activity. These results suggest that TSH, dibutyl cAMP, and Graves' IgG induced I-5'-D activity through the synthesis of new enzyme protein. A significant positive correlation between thyroid-stimulating antibody activity assayed by measuring cAMP production using FRTL-5 cells and I-5'-D activity induced by the Graves' IgG in 10 patients with untreated Graves' disease was observed (r = 0.79; P less than 0.01). The present findings suggest that type I iodothyronine 5'-deiodinase exists in FRTL-5 rat thyroid cells and that Graves' IgG as well as TSH stimulate the activity at least in part by activating adenylate cyclase.

Pup contact induces the expression of long form prolactin receptor mRNA in the brain of female rats: effects of ovariectomy and hypophysectomy on receptor gene expression.

Prolactin receptor (PRL-R) mRNA expression levels in the female rat brain (cerebrum) during pup contact stimulation were determined by the reverse transcription-PCR method. The high expression levels of long form PRL-R mRNA found in the brain of lactating rats were markedly reduced by removal of pups, and long form PRL-R mRNA levels were recovered by resumption of pup contact. Interestingly, pup contact stimuli of nulliparous virgin rats also markedly induced long form but not short form PRL-R mRNA expression in the brain in 1.3 days, together with the expression of maternal behaviour. In ovariectomized (OVX) or hypophysectomized (HYPOX) virgin rats, or in OVX plus HYPOX virgin rats, however, brain long form PRL-R mRNA was not significantly induced by pup contact stimuli for as long as 7 days, while maternal behaviour was fully expressed in these rats after 7 days of pup contact. The in situ hybridization experiments revealed that the long form PRL-R mRNA induced in virgin rats in contact with pups or in lactating rats was localized in the epithelial cells of the choroid plexus. No significant increase in mRNA was detected in other regions of the brain, such as the hypothalamus or cortex, in these maternal female rats. These results suggest that pup contact induces the expression of long form PRL-R mRNA in the choroid plexus of the brain in the presence of female sex steroid and pituitary hormones for the rapid expression of maternal behaviour. Our studies also suggested that maternal behaviour can be expressed in OVX or HYPOX rats after exposure to pups for 7 days without any significant increase in brain PRL-R mRNA expression.

Carcinoma of the pancreas with endocrine component in childhood. A case report.

A case of pancreatic tumor in a six-year-old girl is presented. The tumor had histologic characteristics of acinar cell carcinoma with endocrine component. Grossly, it was encapsulated and attached to the tail of the pancreas, measuring 8 cm in the greatest diameter. Histologically, the tumor was composed of medium-sized tumor cells, with mild pleomorphism showing mainly acinar structures. Many of these tumor cell contained fine granules that were periodic acid-Schiff positive, diastase resistant, and positive with dimethylaminobenzaldehyde nitrite strain for tryptophan, and some contained granules that were positive with Grimelius stain and positive with peroxidase-antiperoxidase technic for gastrin. Electron microscopy revealed two types of membrane-bound granules in the tumor cells. The larger granules measured 400-700 nm in diameter and appeared to be zymogen granules, while the smaller ones measured 100-200 nm in diameter and appeared to be neuroendocrine granules. Some cells contained both granules. The postoperative course of the patient was excellent, and she was alive and well 13 years after operation. This may be the second reported case of acinar-endocrine cell tumor of the pancreas.

Fine structure of connectin nets in cardiac myofibrils.

A net-like structure extending through Z lines of myofibrils in frog cardiac muscle was clearly demonstrated under an electron microscope after the removal of myosin and actin. The diameter of the very thin filaments forming the nets was approximately 2 nm; this width was thinner than that of the actin filament. The net structure is ascribed to connectin, an elastic protein of muscle.

Relation of rat fetal body weight to the relative expression of insulin genes I and II.

This study investigates the relation between the ratio of the abundance of mRNAs encoded by insulin genes I and II (insulin I/II mRNA ratio) and the weight of rat fetuses on gestational day 20. Total RNA was extracted from the pancreas of the fetuses with the maximum and minimum body weight in each litter on gestational day 20. The amount of insulin mRNAs I and II in each RNA preparation was determined by reverse transcription-polymerase chain reaction (RT-PCR) analysis and restriction enzyme digestion. The maximum and minimum weight of the fetuses were 4.07 +/- 0.23 and 3.23 +/- 0.34 g, respectively (N = 18, P < .01) and the corresponding insulin I/II mRNA ratios were 3.65 +/- 0.55 and 1.42 +/- 0.21 (N = 18, P < .01). Furthermore, the insulin I/II mRNA ratio correlated significantly with fetal weight (r = .526, P < .05). These results suggest that the relative expression of insulin genes I and II may affect the extent of fetal growth.

A prospective randomized comparison of routine buserelin acetate and a decreasing dosage of nafarelin acetate with a low-dose gonadotropin-releasing hormone agonist protocol for in vitro fertilization and intracytoplasmic sperm injection.

OBJECTIVE: To compare the efficacy of a draw-back nafarelin acetate protocol with routine buserelin acetate administration for in vitro fertilization (IVF) and intracytoplasmic sperm injection (ICSI). DESIGN: Prospective clinical study. SETTING: Mie University School of Medicine, Tsu, Mie, Japan. PATIENT(S): One hundred sixty-nine women treated with IVF and 183 women treated with ICSI. INTERVENTION(S): Nafarelin acetate and buserelin acetate in ovarian hyperstimulation in IVF and ICSI were administered. MAIN OUTCOME MEASURE(S): The concentrations of estradiol (E(2)), FSH, LH, gonadotropin dosages; the number of oocytes retrieved, oocytes fertilized, and embryos; and pregnancy rates. RESULT(S): A prospective study was conducted with 44 cycles for 34 couples with nafarelin acetate (group 1) and 47 cycles for 40 couples with buserelin acetate (group 2) with a long IVF protocol; 68 cycles for 46 couples with nafarelin acetate (group 3) and 56 cycles for 39 couples with buserelin acetate (group 4) with a short IVF protocol; 39 cycles for 32 couples with nafarelin acetate (group 5) and 50 cycles for 30 couples with buserelin acetate (group 6) with a long ICSI protocol; and 87 cycles for 60 couples with nafarelin acetate (group 7) and 81 cycles for 61 couples with buserelin acetate (group 8) with a short ICSI protocol. Patients were randomized to receive either full-dose nafarelin acetate (200 microg b.i.d.) treatment for 7 days followed by half-dose nafarelin acetate (200 microg daily) or buserelin acetate (300 microg t.i.d.). There were no statistically significant differences in baseline concentrations of E(2) and FSH, concentrations of E(2), P4, FSH, LH on hCG administration, gonadotropin dosage, the number of oocytes retrieved and embryos transferred, or pregnancy rates between groups 1 and 2, groups 3 and 4, groups 5 and 6, and groups 7 and 8. CONCLUSION(S): Full-dose nafarelin acetate treatment for 7 days followed by half-dose nafarelin acetate ("draw-back" protocol) is an effective new protocol for IVF and ICSI.

Type 2 iodothyronine deiodinase expression is upregulated by the protein kinase A-dependent pathway and is downregulated by the protein kinase C-dependent pathway in cultured human thyroid cells.

Type 1 and 2 iodothyronine deiodinases (D1 and D2) catalyze thyroxine (T4) activation. In human thyroid, unlike rodents', both D1 and D2 are expressed. We have investigated the effects of thyrotropin (TSH), dibutyryl cyclic adenosine monophosphate [(Bu)2cAMP] (an activator of protein kinase A [PKA]), 12-O-tetradecanoylphorbor 13-actate (TPA) (an activator of protein kinase C [PKC]), T4, and triiodothyronine (T3) on the D2 mRNA levels and activity in cultured human thyroid cells. D2 mRNA levels were increased by TSH and (Bu)2cAMP, and the increment was faster and greater than that of D1 mRNA levels. The increment of the maximum velocity (Vmax) value for D2 by (Bu)2cAMP stimulation was similar to that of D2 mRNA levels, suggesting that (Bu)2cAMP enhances D2 activity mainly at the pretranslational level. Cycloheximide, a protein synthesis inhibitor, partially inhibited the increase of D2 mRNA levels by (BU)2cAMP, suggesting that de novo protein synthesis-dependent pathways are involved. TPA suppressed the D2 mRNA levels in the presence of (Bu)2cAMP. However, T3 and T4 did not significantly change the D2 mRNA levels and activity. In conclusion, D2 expression in human thyroid cells is more rapidly and strongly upregulated by the PKA pathway than D1 expression, and is downregulated by the PKC pathway.