Therapeutic efficacy and limitations of potassium iodide for patients newly diagnosed with Graves' disease

The efficacy of potassium iodide (KI) for Graves' disease (GD) has been reported, although few clinical reports have examined the long-term efficacy of treatment. The objective of this study was to investigate the efficacy and limitations of KI treatment for GD. This study enrolled patients newly diagnosed with mild GD, defined as free thyroxine (FT4) <5.0 ng/dL, between July 2014 and June 2016. KI was started at a dose of 50 mg/day, and if FT4 values did not decrease after initiation of treatment, doses were increased to 100 mg/day. Patients for whom thyroid hormone levels could not be controlled with KI at 100 mg/day were regarded as non-responders. Of the 122 patients (13 males, 109 females) included in this study, 71 (58.2%) responded to KI therapy. The remaining 51 patients (41.8%) were non-responders. The median duration required to judge non-responsiveness was 5.9 months. Multiple logistic regression analysis performed on parameters measured at the initial visit indicated FT4 (odds ratio (OR) 2.19, 95% confidence interval (CI) 1.28-3.75; p = 0.0007) and male sex (OR 3.58, 95%CI 1.04-12.3; p = 0.04) were significantly associated with KI responsiveness. Receiver operating characteristic (ROC) curve analysis of the relationship between FT4 and KI responsiveness indicated an FT4 cut-off of 2.76 ng/dL was optimal for differentiating between responders and non-responders. KI therapy was effective and safe for about 60% of patients with mild GD.

Characteristics of Patients with Graves' Disease Whose Thyroid Hormone Levels Increase After Substituting Potassium Iodide for Methimazole in the First Trimester of Pregnancy

Background: The clinical course of Graves' disease (GD) in women who switched from methimazole (MMI) to potassium iodide (KI) during the first trimester of pregnancy has never been reported in detail. Objective: To investigate the characteristics of GD patients whose thyroid hormone levels increase after substituting KI for MMI. Patients: Two hundred forty women with GD who had been treated with MMI and switched from MMI to inorganic iodide to control hyperthyroidism during the first trimester between January 1, 2005, and March 31, 2018. Results: In 133 (55.4%) of the GD patients, medication was completely tapered during pregnancy, and the other 107 (44.6%) GD patients were taking medication at delivery: 57 were taking KI alone and 50 were taking an antithyroid drug with or without KI. It was difficult to control the maternal thyrotoxicosis of 22 of the 107 patients with KI alone, and a higher dose of MMI compared with the dose at the time of conception was required (worsened group). Multivariate analysis revealed that the TRAb value at the time of switch from MMI to KI was the only factor that predicted continuation of the thyroid suppression medication, but none of the parameters was a predictor of the worsened group. Conclusions: It must be kept in mind that a certain proportion of GD patients escape from the antithyroid effect of iodide and that careful follow-up is necessary after switching a pregnant patient's medication to KI.

Analysis of Antithyroid Drug-Induced Severe Liver Injury in 18,558 Newly Diagnosed Patients with Graves' Disease in Japan

Background: The prevalence of antithyroid drug (ATD)-related drug-induced liver injury (DILI) has been reported to vary among patients in several countries. The purpose of this study was to summarize the prevalence of liver injury induced by ATD and to determine the actual prevalence of severe liver injury. Methods: The medical records of 18,558 patients who were newly diagnosed with Graves' disease between January 2005 and December 2016 were retrospectively reviewed. Severe DILI was defined as alanine aminotransferase (ALT) 8 times higher than the upper limit of normal (ULN) or total bilirubin (T-bil) 3 times higher than the ULN. The most severe DILI was defined as ALT higher than 20 times the ULN or T-bil higher than 10 times the ULN. Results: A total of 461 subjects (470 cases) were analyzed, and they consisted of 10 males and 451 females, with a median age of 37 years (range 10-82 years). Nine of 461 patients had severe DILI with both drugs. The total prevalence of severe DILI in this study was 2.5%, and the prevalence of DILI by drug was 1.4% with metimazole (MMI) (n = 198) and 6.3% with propylthiouracil (PTU) (n = 272) (p < 0.001). The prevalence of the most severe ATD-related DILI was 0.22% (n = 40), and the prevalence for each drug was 0.08% with MMI (n = 11) and 0.68% with PTU (n = 29). The median time to DILI development was 30 days (range 7-314 days), and all patients recovered from DILI, with no fatalities. The prevalence of MMI-related DILI was significantly age dependent (p < 0.001). Conclusions: Though there were no fatalities in this study, the prevalence of PTU-related severe DILI was significantly higher than that of MMI-related severe DILI.

Predictors of Clinical Success After Surgery for Primary Aldosteronism in the Japanese Nationwide Cohort

Context

Aldosterone-producing adenomas are a curable subtype of primary aldosteronism (PA); however, hypertension persists in some patients after adrenalectomy.

Objective

To identify factors associated with, and develop prediction models for, blood pressure (BP) normalization or improvement after adrenalectomy.

Design

Retrospective analysis of patients treated between 2006 and 2018, with a 6-month follow-up.

Setting

A nationwide, 29-center Japanese registry encompassing 15 university hospitals and 14 city hospitals.

Patients

We categorized 574 participants in the Japan Primary Aldosteronism Study, who were diagnosed with PA and underwent adrenalectomy, as BP normalized or improved, on the basis of their presentations at 6 months postsurgery.

Main Outcome Measure

The rate of complete, partial, and absent clinical success. Predictive factors related to BP outcomes after PA surgery were also evaluated.

Results

Complete clinical success was achieved in 32.6% and partial clinical success was achieved in 53.0% of the patients at 6 months postsurgery. The following five variables were independent predictors for BP normalization: ≤7 years of hypertension, body mass index ≤25 kg/m², no more than one antihypertensive medication, absence of medical history of diabetes, and female sex. The area under the receiver operator characteristic curve was 0.797 in the BP normalization model.

Conclusion

We established models that predicted postoperative BP normalization in patients with PA. These should be useful for shared decision-making regarding adrenalectomy for PA.

Epidermal growth factor receptor/extracellular signal-regulated kinase pathway enhances mineralocorticoid receptor transcriptional activity through protein stabilization

Activation of mineralocorticoid receptor (MR) is evoked by aldosterone, and it induces hypertension and cardiovascular disease when it's concomitant with excessive salt loading. We have proposed the notion of "MR-associated hypertension", in which add-on therapy of MR blockers is effective even though serum aldosterone level is within normal range. To elucidate its underlying molecular mechanism, we focused on the effect of epidermal growth factor receptor (EGFR)/extracellular signal-regulated kinase (ERK) activation on MR activity. Epidermal growth factor (EGF) administration increased MR transcriptional activity through EGFR/ERK pathway and increased protein level by counteracting MR ubiquitylation in vitro. EGF administration in vivo also increased MR protein level and target gene expression in kidney, which were decreased by EGFR inhibitor. In addition, the administration of EGFR inhibitor lowered systolic blood pressure and MR activity in DOCA/salt-treated mice. In conclusion, EGFR/ERK pathway activation is considered as one of the underlying mechanisms of aberrant MR activation and EGFR/ERK pathway blockade could be an alternative approach for the prevention of MR-related cardiovascular events.

Intestinal Mineralocorticoid Receptor Contributes to Epithelial Sodium Channel-Mediated Intestinal Sodium Absorption and Blood Pressure Regulation

Background

Mineralocorticoid receptor (MR) has pathological roles in various cell types, including renal tubule cells, myocytes, and smooth muscle cells; however, the role of MR in intestinal epithelial cells (IECs) has not been sufficiently evaluated. The intestine is the sensing organ of ingested sodium; accordingly, intestinal MR is expected to have essential roles in blood pressure (BP) regulation.

Methods and Results

We generated IEC‐specific MR knockout (IEC‐MR‐KO) mice. With a standard diet, fecal sodium excretion was 1.5‐fold higher in IEC‐MR‐KO mice, with markedly decreased colonic expression of β‐ and γ‐epithelial sodium channel, than in control mice. Urinary sodium excretion in IEC‐MR‐KO mice decreased by 30%, maintaining sodium balance; however, a low‐salt diet caused significant reductions in body weight and BP in IEC‐MR‐KO mice, and plasma aldosterone exhibited a compensatory increase. With a high‐salt diet, intestinal sodium absorption markedly increased to similar levels in both genotypes, without an elevation in BP. Deoxycorticosterone/salt treatment elevated BP and increased intestinal sodium absorption in both genotypes. Notably, the increase in BP was significantly smaller in IEC‐MR‐KO mice than in control mice. The addition of the MR antagonist spironolactone to deoxycorticosterone/salt treatment eliminated the differences in BP and intestinal sodium absorption between genotypes.

Conclusions

Intestinal MR regulates intestinal sodium absorption in the colon and contributes to BP regulation. These regulatory effects are associated with variation in epithelial sodium channel expression. These findings suggest that intestinal MR is a new target for studying the molecular mechanism of hypertension and cardiovascular diseases.

Synthesis of 15alpha-fluoro-24,25-dihydrolanosterol as a potential inhibitor and/or mechanistic probe for lanosterol 14alpha-demethylase

As a potential inhibitor and/or mechanistic probe for lanosterol 14alpha-demethylase, 15alpha-fluoro-24,25-dihydrolanosterol was prepared by fluorination of 15alpha-hydroxy-24,25-dihydrolanost-7-en-3beta-yl benzoate with diethylaminosulfur trifluoride, followed by hydrogen chloride-catalyzed isomerization of the delta7 to delta8 and reductive cleavage of the benzoate.

[Studies on the biosynthesis of sterol side chain in higher plants]

Campesterol (3) and dihydrobrassicasterol (4), typical C28-sterols in higher plants, are biosynthesized from a steroidal 24-ene precursor (desmosterol 1) via 24-methylenecholesterol (2) and 24-methyldesmosterol (5). A typical plant C29-sterol, sitosterol (6), is produced from 24-methylenecholesterol via isofucosterol (7) and 24-ethyldesmosterol (8). The biosynthetic mechanism, focussing stereochemical features, of these side-chain transformations has been studied in detail by feeding regio- and stereoselectively 13C- or 2H-labeled steroidal substrates to cell cultures of higher plants such as Oryza sativa, Catharanthus roseus and Morus alba. These studies allowed to correlate the metabolic origin of C-26 and C-27 of the intermediate sterols. It has been established that the 1st methylation leading to 24-methylenecholesterol from desmosterol involves a Re-face hydrogen migration from C-24 to C-25 based on unambiguous assignment of the isopropyl pro-R-Me and pro-S-Me of 24-methylenecholesterol. The 2nd methylation leading to isofucosterol was revealed to proceed in a trans-mechanism in which addition of the methyl group and elimination of the C-28 hydrogen occur on opposite faces of the original delta 24(28) plane. The double bond isomerization from delta 24(28) to delta 24(25) was found to proceed in a syn-SE2' mechanism with the pro-S-methyl group of isofucosterol becoming the (E)-methyl of 24-ethyldesmosterol. Finally, feeding studies of [E-Me-13C]- and [Z-Me-13C]-24-methyldesmosterols established that an anti-mode of hydrogen addition is operating in the conversion of 24-methyldesmosterol to campesterol and dihydrobrassicasterol. Similar studies established that 24-ethyldesmosterol is converted to sitosterol in an anti-mode of hydrogen addition. In addition, the mechanism of sterol side-chain formation in hairy roots of Ajuga reptans var. atropurpurea is briefly described.

Stereochemical fate of C-26 and C-27 during the conversion of isofucosterol to sitosterol and of 24-methylenecholesterol to campesterol and dihydrobrassicasterol in Oryza sativa cell cultures

Administration of pro-R-methyl-13C-labeled isofucosterol to cultured cells of Oryza sativa revealed that the pro-R and pro-S methyls at C-25 become the pro-R and pro-S methyls at C-25 of sitosterol, respectively. Similar administration experiments using pro-S-methyl-13C-labeled 24-methylenecholesterol established that the pro-R and pro-S methyls at C-25 of 24-methylenecholesterol become the pro-R and pro-S methyls of campesterol, and the pro-S and pro-R methyls of dihydrobrassicasterol, respectively. These results are compatible with our recently proposed 'syn-SE2' mechanism' for double bond isomerization of delta 24(28) into delta 24(25).

Biosynthesis of sterols and ecdysteroids in Ajuga hairy roots

Hairy roots of Ajuga reptans var. atropurpurea produce clerosterol, 22-dehydroclerosterol, and cholesterol as sterol constituents, and 20-hydroxyecdysone, cyasterone, isocyasterone, and 29-norcyasterone as ecdysteroid constituents. To better understand the biosynthesis of these steroidal compounds, we carried out feeding studies of variously 2H- and 13C-labeled sterol substrates with Ajuga hairy roots. In this article, we review our studies in this field. Feeding of labeled desmosterols, 24-methylenecholesterol, and 13C2-acetate established the mechanism of the biosynthesis of the two C29-sterols and a newly accumulated codisterol, including the metabolic correlation of C-26 and C-27 methyl groups. In Ajuga hairy roots, 3alpha-, 4alpha-, and 4beta-hydrogens of cholesterol were all retained at their original positions after conversion into 20-hydroxyecdysone, in contrast to the observations in a fern and an insect. Furthermore, the origin of 5beta-H of 20-hydroxyecdysone was found to be C-6 hydrogen of cholesterol exclusively, which is inconsistent with the results in the fern and the insect. These data strongly support the intermediacy of 7-dehydrocholesterol 5alpha,6alpha-epoxide. Moreover, 7-dehydrocholesterol, 3beta-hydroxy-5beta-cholest-7-en-6-one (5beta-ketol), and 3beta,14alpha-dihydroxy-5beta-cholest-7-en-6-one (5beta-ketodiol) were converted into 20-hydroxyecdysone. Thus, the pathway cholesterol-->7-dehydrocholesterol-->7-dehydrocholesterol 5alpha,6alpha-epoxide-->5beta-ketol-->5beta-k etodiol is proposed for the early stages of 20-hydroxyecdysone biosynthesis. 3beta-Hydroxy-5beta-cholestan-6-one was also incorporated into 20-hydroxyecdysone, suggesting that the introduction of a 7-ene function is not necessarily next to cholesterol. C-25 Hydroxylation during 20-hydroxyecdysone biosynthesis was found to proceed with ca. 70% retention and 30% inversion. Finally, clerosterol was shown to be a precursor of cyasterone and isocyasterone.

Stereochemistry of the reduction of 24-ethyldesmosterol to sitosterol in tissue cultures of Oryza sativa

Feeding of [26-13C]- and [27-13C]-24-ethyldesmosterols to cultured cells of Oryza sativa followed by 13C-NMR analysis of the biosynthesized sitosterol revealed that the reduction of 24(25)-double bond proceeds with an anti-addition of hydrogen atoms, thus the E-methyl group of the olefinic precursor becomes the pro-S-methyl on C-25 of sitosterol.

Non-stereoselective formation of 3 alpha,7 alpha,12 alpha,24-tetrahydroxy-5 beta-cholestan-26-oic acid during cholic acid biosynthesis

Incubation of (25RS)-, (25R)- and (25S)-3 alpha,7 alpha,12 alpha-trihydroxy-5 beta-cholestan-26-oic acid (THCA, 6, 6a, 6b) and (24E)-3 alpha,7 alpha,12 alpha-trihydroxy-5 beta-cholest-24-en-26-oic acid (7) with rat liver mitochondria gave all four stereoisomers (9a,9b,9c,9d) of 3 alpha,7 alpha,12 alpha,24-Tetrahydroxy-5 beta-cholestan-26-oic acid (TeHCA). The corresponding 27-nor analogs (10,11) were also converted non-stereoselectively to a 1:1 mixture of the epimeric 24-hydroxy compounds (12).

Stereochemistry of hydrogen addition to C-25 of desmosterol by sterol-delta 24-reductase of rat liver homogenate

Chemically synthesized (26)- and (27)-methyl-13C-labeled desmosterol (3, 5) were separately incubated with rat liver homogenate. 13C-NMR analysis of the incubation products indicated that the C-25 hydrogen of cholesterol was introduced from the si-face of 3 and the re-face of 5.

Identification of 27-nor-3 alpha, 7 alpha, 12 alpha-trihydroxycoprostan-24-one apparently derived from 3 alpha, 7 alpha, 12 alpha-trihydroxy-24-oxocoprostanoic acid, a postulated intermediate of bile acid biosynthesis

Incubation of [27-13C]-3 alpha, 7 alpha, 12 alpha-trihydroxycoprost-24-en-26-oic acid with rat liver homogenate followed by 13C-NMR analysis of the incubation product has resulted in the identification of [26-13C]-27-nor-3 alpha, 7 alpha, 12 alpha-trihydroxycoprostan-24-one, supporting the idea that the substrate has been metabolized into 3 alpha, 7 alpha, 12 alpha-trihydroxy-24-oxocoprostan-26-oic acid CoA derivative.

Identification of cholesta-7,24-dien-3 beta-ol and desmosterol in hamster cauda epididymal spermatozoa

The sterol composition of hamster cauda epididymal spermatozoa was remarkably different from that of several other mammalian spermatozoa. Desmosterol and cholesta-7,24-dien-3 beta-ol account for as much as 90% of the total sterols. Cholesterol and desmosterol are the major components of mouse cauda epididymal spermatozoa, and rabbit, boar and bull ejaculated spermatozoa. Cholesta-7,24-dien-3 beta-ol was not detected. Furthermore, cholesterol was the main sterol in hamster caput epididymal spermatozoa, while only a trace amount of desmosterol was detected and cholesta-7,24-dien-3 beta-ol was hardly detected at all. The sterol content of cauda and caput epididymal spermatozoa was 0.17 +/- 0.05 mumol/10(8) spermatozoa. During maturation, the desmosterol and cholesta-7,24-dien-3 beta-ol levels increase and the cholesterol level decreases. Cholesta-7,24-dien-3 beta-ol appears as a sterol in mature spermatozoa and seems to be a characteristic sterol of hamster cauda epididymal spermatozoa.

Role of cholesterol 10-methyl group and effect of "extra" 14-methyl group on silkworm growth and development

In order to establish the functional importance of the 10-methyl group of cholesterol and the planarity of the steroid ring, silkworms (Bombyx mori) were reared on an artificial diet containing 19-norcholesterol (1), 14 alpha-methylcholesterol (3) or 19,19-difluorocholesterol (2). The former two sterols (1 and 3) only partially satisfied the silkworm sterol requirement; growth and development were seriously retarded. The fluorinated sterol (2) was much more deleterious and was totally inadequate in meeting the sterol requirement.

Participation of histidine in biosynthesis of the pyrimidine moiety of thiamin in Saccharomyces cerevisiae

The amide nitrogen atom of glutamine is incorporated into the pyrimidine moiety of thiamin in Escherichia coli and Saccharomyces cerevisiae. However, addition of casamino acids to the medium increases incorporation of the amide nitrogen atom of glutamine in E. coli, but decreases it in S. cerevisiae. This suggests that some amino acids other than glutamine in casamino acids are more direct precursors of the pyrimidine moiety in S. cerevisiae. To determine the direct precursor, we investigated the competitive effect of 14N-amino acids on the incorporation of 15NH4Cl into the pyrimidine moiety and found that histidine decreased the incorporation of 15N. Thus, histidine was concluded to be the direct precursor of the nitrogen atom of the pyrimidine moiety of thiamin in S. cerevisiae.

Biosynthesis of thiamin. Different biosynthetic routes of the thiazole moiety of thiamin in aerobic organisms and anaerobic organisms

The nitrogen atom of glycine was incorporated into the thiazole moiety of thiamin in the aerobic microorganisms Bacillus subtilis, Pseudomonas putida, Saccharomyces cerevisiae, Mucor racemosus, Neurospora crassa, and Emericella nidulans. It was not incorporated in the case of the facultative anaerobic microorganisms Escherichia coli and Enterobacter aerogenes, which, however, did incorporate the nitrogen atom of tyrosine. These results show that aerobic microorganisms and facultative anaerobic microorganisms have different biosynthetic pathways for the thiazole moiety of thiamin.

Inhibitory effect of 15-oxygenated sterols on cholesterol synthesis from 24,25-dihydrolanosterol

Several 15-oxygenated sterols were examined as to their inhibitory activity toward cholesterol synthesis from [24,25-3H]-24,25-dihydrolanosterol in the 10,000 X g supernatant fraction of a rat liver homogenate. At 40 microM, three 15 alpha-hydroxylated compounds, 14 alpha-ethylcholest-7-ene-3 beta,15 alpha-diol, 14 alpha-methylcholest-7-ene-3 beta,15 alpha-diol, and lanost-7-ene-3 beta,15 alpha-diol, were found to be extremely potent inhibitors (more than 90% inhibition) of dihydrolanosterol metabolism. The inhibitory effect of the C-15 substituents appeared to be in the order of: 15 alpha-hydroxyl greater than 15-ketone greater than 15 beta-hydroxyl.

Rapid modulation of platelet aggregation in plasma by oxygenated sterols

The effect of oxygenated sterols on platelet aggregation induced by thrombin and ADP has been studied. All oxygenated sterols tested with a hydroxyl group on the side chain enhanced thrombin-induced aggregation at 25 microM. In the case of ADP-induced aggregation, however, only 22S-hydroxycholesterol[(22S)-5-cholestene-3 beta,22-diol] enhanced the aggregation, and 22R-hydroxycholesterol[(22R)-5-cholestene-3 beta,22-diol], 24S-hydroxycholesterol[(24S)-5-cholestene-3 beta,24-diol], and 25-hydroxycholesterol[5-cholestene-3 beta,25-diol] inhibited it. These effects were observed within 10 min after the addition of oxygenated sterols to platelet suspensions in plasma.

Sitosterol-stimulative production of plasminogen activator in cultured endothelial cells from bovine carotid artery

The endothelial cell is a rich source of plasminogen activator that is associated with fibrinolytic activity in blood vessel. Addition of sitosterol to the culture medium of endothelial cells from bovine carotid artery gave rise to a marked increment in the activity of plasminogen activator. Removal of sitosterol from the culture medium resulted in a decrease of plasminogen activator activity back to normal levels. Enhancement of plasminogen activator activity in cultured endothelial cells was not observed by cholesterol, 5-androsten-3 beta-ol and others.

Different biosynthetic pathways of the pyrimidine moiety of thiamin in procaryotes and eucaryotes

[14C]Formate is incorporated into the C-2 of the pyrimidine moiety of thiamin by Escherichia coli and Salmonella typhimurium. In Saccharomyces cerevisiae, it is incorporated into C-4. Radioactive carbons of [1-14C]glycine and [2-14C]glycine are incorporated by S. typhimurium into the C-4 and C-6 of the pyrimidine, respectively, but not by S. cerevisiae. These facts suggest that procaryotes and eucaryotes have different biosynthetic pathways for pyrimidine. In this study, the procaryotes tested incorporated [14C]formate into the C-2 and the eucaryotes incorporated it into the C-4 of the pyrimidine.

Structural requirement of sterol nucleus for the silkworm growth and development

Several cholesterol analogs structurally modified in nuclear substitutions were tested for sustaining the growth of the silkworm Bombyx mori. 5 alpha-Cholest-7-en-3 beta-o1, 5,7-cholestadien-3 beta-o1 and cholesteryl acetate can replace cholesterol as sterol source for B. mori. Considerably good growth was also obtained with 5 alpha-cholest-14-en-3 beta-o1 and 5 alpha-cholesta-6,8(14)-dien-3 beta-o1. Other sterols tested were either partially effective or ineffective as nutrients.

[A study on luteal function during consecutive cycles (author's transl)]

It is conceivable that luteal function is varied with different menstrual cycles. A study was therefore undertaken to investigate for changes in luteal function during consecutive menstrual cycles.

METHODS

From those women receiving ambulatory treatment at the hospital 30 displaying a biphasic basal body temperature (BBT) curve were chosen for the study. BBT records were obtained from each of these women for at least 3 consecutive cycles and a total of 194 cycles thus rendered available were evaluated for the pattern of BBT, the duration of high phase (DHP), high phase score (HPS) and planimetric luteal index (PLI). Twenty of these 30 women were subjected further to endometrial dating at the 7th-8th day of high phase with simultaneous determinations of serum estradiol (E2), progesterone (P) and prolactin (PRL) during 2 consecutive cycles.

RESULTS

The incidences of abnormal values of the parameters for at least one of the consecutive cycles studied were: DHP; 13.3% pattern; 50-100%, HPS; 40.0%, PLI; 13.3%, E2; 25%, P; 25%, PRL; 30%, endometrial dating; 65%. These results indicate a considerable variability of luteal function.

Structural requirement of sterol side chain for the silkworm growth and development

Several cholesterol analogs with modifications in the side chain were added to the artificial diet of the silkworm, and their effects on insect growth and development were determined. It was found that slight deviations of the cholesterol's side chain induced pronounced growth-retarding effects, suggesting an important functional role of the isooctane side chain of cholesterol.

[A study on the significance of bromocriptine (CB-154) administration in normoprolactinemic anovulatory women (author's transl)]

The ovulation-inducing effect of bromocriptine (CB-154) and the underlying mechanism in the management of anovulatory infertility with normoprolactinemia were investigated. Thirty-seven normoprolactinemic women (anovulatory cycle, 11 cases; 1st grade amenorrhea, 18; and 2nd grade amenorrhea 8) with anovulia showing plasma prolactin levels of less than 25 ng/ml were give CB-154 daily in doses of 2.5 mh from the second day of menstruation or withdrawal bleeding (1) to assess the ovulatory induction rate, (2) to determine the serum PRL, LH, FSH and E2 levels before and during the drug administration, (3) to measure the serum PRL concentration by TRH test prior to CB-154 medication and (4) to assess size heterogeneity of serum PRL with the use of lyophilization.

RESULTS

(1) Ovulation occurred in 21 of the 37 patients, of a total of 42 menstrual cycles studied, 33 were ovulatory, indicating a high rate of repeated success. (2) There was a significant decrease of serum PRL following administration of CB-154, and the finding was the same in the group of women with successful ovulatory induction. Serum LH, FSH and E2 levels did not show any significant change following CB-154 therapy. (3) Prl concentrations were suppressed more in cases of unsuccessful induction than those in successful induction. (4) PRL responses to TRH tended to be lower in cases of successful induction than those in unsuccessful cases. (5) The Little PRL content ratio decreased after administration of CB-154, and this data have suggested that not only the problem of immunologically measured serum PRL levels but the qualitative problems also bear relations to the effect of this hormone on the endocrinological environment.

Stereochemical importance of fucosterol epoxide in the conversion of sitosterol into cholesterol in the silkworm Bombyx mori

Studies on the stereochemistry of 24,28-epoxy-24-ethylcholesterol, a key intermediate in sitosterol to cholesterol conversion in insects, were undertaken. In nutritional experiments, the 24R,28S and 24S,28R stereoisomers (isofucosterol epoxides) were unable to support growth and development of silkworm larvae. Incubation of 3 alpha-3H-labeled (24R,28R)- and (24S,28S)-epoxide (fucosterol epoxides) with a cell-free preparation from silkworm guts resulted in effective conversion into desmosterol and cholesterol; (24R,28R)-epoxide was the slightly better substrate. Fucosterol incubation yielded (24R,28R)-epoxide and the 24S,28S isomer in approximately equal amounts, while slightly preferential formation of the 24R,28R isomer was observed in in vivo experiments. These results indicate that both the formation of the epoxide from fucosterol and its conversion to desmosterol proceed with a low degree of stereospecificity.

Biological activity of 24,24-difluoro-25-hydroxyvitamin D3. Effect of blocking of 24-hydroxylation on the functions of vitamin D

To examine the question of whether 24-hydroxylation plays and importance role in the physiological functions of vitamin D, the biological activity of 24,24-difluoro-25-hydroxyvitamin D was compared with that of 25-hydroxyvitamin D in vitamin D-deficient rats. These two compounds were found almost identically active in the stimulation of intestinal calcium transport, the mobilization of calcium from bone, the healing of rachitic epiphyseal plate cartilage, the elevation of serum inorganic phosphorus, the mineralization of rachitic bone, and in the prevention of rachitogenesis in rats. Little or no difference was detected in the time course of response of intestinal calcium transport or bone calcium mobilization to the two forms of vitamin D. Therefore, in the rat no support could be obtained for the idea that 24,25-dihydroxyvitamin D3 plays an important role in the known physiological responses to the vitamin.