Ensuring quality in 17OHP mass spectrometry measurement: an international study assessing isomeric steroid interference

OBJECTIVES

Interference from isomeric steroids is a potential cause of disparity between mass spectrometry-based 17-hydroxyprogesterone (17OHP) results. We aimed to assess the proficiency of mass spectrometry laboratories to report 17OHP in the presence of known isomeric steroids.

METHODS

A series of five samples were prepared using a previously demonstrated commutable approach. These samples included a control (spiked to 15.0 nmol/L 17OHP) and four challenge samples further enriched with equimolar concentrations of 17OHP isomers (11α-hydroxyprogesterone, 11β-hydroxyprogesterone, 16α-hydroxyprogesterone or 21-hydroxyprogesterone). These samples were distributed to 38 participating laboratories that reported serum 17OHP results using mass spectrometry in two external quality assurance programs. The result for each challenge sample was compared to the control sample submitted by each participant.

RESULTS

Twenty-six laboratories (68 % of distribution) across three continents returned results. Twenty-five laboratories used liquid chromatography-tandem mass spectrometry (LC-MS/MS), and one used gas chromatography-tandem mass spectrometry to measure 17OHP. The all-method median of the control sample was 14.3 nmol/L, ranging from 12.4 to 17.6 nmol/L. One laboratory had results that approached the lower limit of tolerance (minus 17.7 % of the control sample), suggesting the isomeric steroid caused an irregular result.

CONCLUSIONS

Most participating laboratories demonstrated their ability to reliably measure 17OHP in the presence of the four clinically relevant isomeric steroids. The performance of the 12 (32 %) laboratories that did not engage in this activity remains unclear. We recommend that all laboratories offering LC-MS/MS analysis of 17OHP in serum, plasma, or dried bloodspots determine that the isomeric steroids are appropriately separated.

Detection of boldenone in the urine of female horses-ex vivo formation versus administration

Boldenone is an anabolic-androgenic steroid (AAS) that is prohibited in equine sports. However, in certain situations, it is endogenous, potentially formed by the microbes in urine. An approach to the differentiation based on the detection of the biomarkers Δ1-progesterone, 20(S)-hydroxy-Δ1-progesterone and 20(S)-hydroxyprogesterone was assessed, and their concentrations were monitored in the urine of untreated female horses (n = 291) alongside boldenone, boldienone, testosterone and androstenedione. Using an ultra-sensitive analytical method, boldenone (256 ± 236 pg/mL, n = 290) and the biomarkers (Δ1-progesterone up to 57.6 pg/mL, n = 8; 20(S)-hydroxy-Δ1-progesterone 85.3 ± 181 pg/mL, n = 130; 20(S)-hydroxyprogesterone 43.5 ± 92.1 pg/mL, n = 158) were detected at low concentrations. The ex vivo production of Δ1-steroids was artificially induced following the storage of urine samples at room temperature for 7 days in order to assess the concentrations and ratios of the monitored steroids. The administration of inappropriately stored feed source also resulted in an increase in 20(S)-hydroxy-Δ1-progesterone concentrations and the biomarker ratios. Using the results from different datasets, an approach to differentiation was developed. In situations where the presence of boldenone exceeds a proposed action limit of 5 ng/mL, the presence of the biomarkers would be investigated. If Δ1-progesterone is above 50 pg/mL or if 20(S)-hydroxy-Δ1-progesterone is above 100 pg/mL with the ratio of 20(S)-hydroxy-Δ1-progesterone:20(S)-hydroxyprogesterone greater than 5:1, then this would indicate ex vivo transformation or consumption of altered feed rather than steroid administration. There remains a (small) possibility of a false negative result, but the model increases confidence that adverse analytical findings reported in female horses are caused by AAS administrations.

Effect of weekly 17-hydroxyprogesterone caproate on small for gestational age among pregnant women with HIV in Zambia

The IPOP trial demonstrated a reduced risk of severe small for gestational age among infants born to women with HIV who received weekly intramuscular 17 alpha-hydroxyprogesterone caproate. This secondary analysis examined the 17P treatment effect in subgroups of maternal BMI, parity, timing of antiretroviral therapy (ART) initiation, and ART regimen. We found that 17P was more effective among nulliparous women, women who started ART before pregnancy, and those taking protease inhibitors.

Measurement of hair thyroid and steroid hormone concentrations in the rat evidence endocrine disrupting potential of a low dose mixture of polycyclic aromatic hydrocarbons

Polycyclic aromatic hydrocarbons (PAHs) have been shown to influence endogenous hormones levels in animal models, but little is known about the effects of their mixtures. For hormone measurements, hair analysis is a promising approach to provide information on long-term status of hormones. Herein we used hair analysis to assess the combined effects of 13 PAHs on steroid and thyroid hormones levels in a rat model. The PAH mixture was administered orally three times per week to female rats at doses of 0, 10, 20, 40, 80, 200, 400 and 800 μg/kg of body weight for each compound over a 90-day exposure period. Fourteen out of 36 analyzed hormones were detected in rat hair, including pregnenolone (P5), 17α-hydroxyprogesterone (17-OHP4), corticosterone (CORT), dehydroepiandrosterone (DHEA), androstenedione (AD), 3,3'-diiodo-L-thyronine (T2), 3,3',5-triiodo-L-thyronine (T3), and 3,5,3',5'-triiodo-L-thyronine (T4). The PAH mixture significantly elevated P5 and DHEA levels at the doses of 200 and 400 μg/kg but reduced T2 and T3 levels at the highest dose as compared to the control. While P5, DHEA, 17-OHP4 and AD concentrations exhibited inverted U-shaped dose responses, T2, T3 and T4 concentrations exhibited inverse linear dose responses, which are further confirmed by their relationships with hair hydroxylated PAHs (OH-PAHs) concentrations. Likewise, there were significant nonmonotonic relationships of hormone molar ratios (e.g., AD/17-OHP4 and DHEA/CORT ratios) with exposure intensity and OH-PAHs. Overall, our results demonstrate the capability of PAH mixtures to interfere with steroid and thyroid hormones in female rats.

[Clinical and StAR genetic characteristics of 33 children with congenital lipoid adrenal hyperplasia]

Objective: To analyze the clinical and genetic characteristics of 33 children with congenital lipoid adrenal hyperplasia (CLAH) caused by StAR gene defects. Methods: The clinical, biochemical, genetic, and follow-up (until December 2021) data of 33 children diagnosed with CLAH from 2006 to 2021 were retrospectively analyzed in Xinhua Hospital, Shanghai Jiao Tong University School of Medicine. Results: Of the 33 children with CLAH, 17 had a karyotype of 46, XX and 16 had a karyotype of 46, XY; 31 were female and 2 were male by social gender. Classic type and non-classic type were found in 30 and 3 children respectively. The age at diagnosis was 9.0 (3.0, 34.5) months. All the 30 cases with classic CLAH presented within the first year of life with skin hyperpigmentation (28 cases, 93%), vomiting and(or) diarrhea (19 cases, 63%), no increase in body weight (8 cases, 27%), elevated adrenocorticotropic hormone levels (21cases (70%)>275 pmol/L), decreased cortisol levels (47 (31,126) nmol/L), hyponatremia ((126±13) mmol/L), hyperkalemia ((5.7±1.1) mmol/L), and normal 17α-hydroxyprogesterone levels (30 cases, 100%). All these with classic CLAH exhibited female external genitalia. Three children with non-classic CLAH (including 2 cases of 46, XY and 1 case of 46, XX) also showed signs and symptoms of adrenal insufficiency, but 2 of them had an age of onset later than 1 year of age, including 1 case of 46, XY with male external genitalia and 1 case of 46, XX with female external genitalia. The other 46, XY patient with non-classic CLAH presented with adrenal insufficiency at 2 months of age, showing micropenis and hypospadias. In the 17 females with 46, XX, 4 older than 10 years of age showed spontaneous pubertal development. A total of 25 StAR gene pathogenic variants were identified in 33 patients, with p.Q258* (18/66, 27%), p.K236Tfs*47 (8/66, 12%) and p.Q77* (6/66, 9%) being the common variantion. Six novel variants were found, including c.358T>G, c.713_714del, c.125del, c.745-1G>A, c.179-2A>C, and exon 1 deletion. Conclusions: Patients with classic CLAH typically present with signs and symptoms of primary adrenal insufficiency in the early infancy period and female external genitalia. p.Q258*, p.K236Tfs*47 and p.Q77* are common variants in CLAH patients.

Engineering of a fungal steroid 11α-hydroxylase and construction of recombinant yeast for improved production of 11α-hydroxyprogesterone

Cytochrome P450 enzyme CYP68J5 from filamentous fungus Aspergillus ochraceus is industrially used for selective C11α-hydroxylation of canrenone and progesterone. To improve its selectivity of C11α-hydroxylation for relevant steroid substrates, a sequence-based targeted mutagenesis combined with saturation mutagenesis was conducted to search for variants with improved hydroxylation reaction specificity toward progesterone and D-ethylgonendione. Recombinant yeast expressing triple mutant V64F/E65G/N66T showed significantly increased C11α-hydroxylation selectivity (85 % VS WT 69.7 %). Saturation mutagenesis of V64, E65 and N66 resulted in the identification of single mutant V64K with greatly enhanced 11α-hydroxylation specificity toward progesterone (90.6 % VS WT 69.7 %). Furthermore, mutant N66D showed significant enhanced selectivity of C11α-hydroxylation toward D-ethylgonendione (70.8 % VS WT 58 %). Evaluation of recombinant yeast over-expressing V64K for progesterone transformation in 50 mL scale resulted in product 11α-OH progesterone concentrations of 432.5 mg/L, a 30.2 % increase compared with the CYP68J5 control. Our results also reveal that V64, E65 and N66 are key residues of CYP68J5 influencing its selectivity of C11α-hydroxylation, thus offering opportunities for further engineering of CYP68J5 for expanded industrial applications.

Coherent backscattering enhancement in cavities. Highlights of the role of symmetry

Through experiments and simulations, the consequences of symmetry on coherent backscattering enhancement (CBE) are studied in cavities. Three main results are highlighted. First, the CBE outside the source is observed: (a) on a single symmetric point in a one-dimensional (1-D) cavity, in a disk and in a symmetric chaotic plate; (b) on three symmetric points in a two-dimensional (2-D) rectangle; and (c) on seven symmetric points in a three-dimensional (3-D) parallelepiped cavity. Second, the existence of enhanced intensity lines and planes in 2-D and 3-D simple-shape cavities is demonstrated. Third, it is shown how the anti-symmetry caused by the special boundary conditions is responsible for the existence of a coherent backscattering decrement with a dimensional dependence of R = (½)(d), with d = 1,2,3 as the dimensionality of the cavity.

Pregnancy maintenance and the inhibition of parturition in rats with 17alpha-hydroxyprogesterone esters: the role of oestrogenic and androgenic activity

17α-Hydroxyprogesterone acetate (AP) and 17α-hydroxyprogesterone caproate (HPC) were found to be incapable of maintaining pregnancy in ovariectomized rats when administered alone, even if administration of the drugs was started several days prior to surgery. Further studies with AP demonstrated that it could maintain pregnancy in the castrate rat when oestrone or testosterone propionate (TP) were concomitantly administered. The addition of TP to a regimen of concomitant AP and oestrone did not result in further improvement in the quality of pregnancy maintenance. TP and oestrone alone or together were incapable of maintaining pregnancy. Parturition could be delayed or prevented in intact rats with either progesterone or TP when administration of the steroids was started 3 days before the date of expected delivery. HPC and AP alone or with oestrone, and oestrone alone did not delay parturition when administration was begun late in pregnancy. Parturition was prevented when administration of AP was begun at least 11 days before expected delivery.

Transformation of steroids by spores of microorganisms. I. Hydroxylation of progesterone by conidia of Aspergillus ochraceus

Conidia of Aspergillus ochraceus convert progesterone into 11alpha-hydroxyprogesterone and 6beta, 11alpha-dihydroxyprogesterone. The conversion ability does not depend on the sporulation medium. Transformation depends on the strain and on the conidia concentration. Adaptation has never been observed. Age and storage of conidia, pH, aeration-agitation, nitrogen source, metal ions, chelating agents, and metabolic activators showed no great influence within wide limits. Mercuric chloride, p-chloromercuribenzoate, NaN(3), and KCN inhibit conversion. Glucose is necessary, but can be replaced completely by d(+)-xylose, and partially by some other carbon sources. The ratio mono-/di-hydroxyprogesterone is influenced by progesterone concentration and period of incubation; also, a mutant that accumulates only monohydroxyprogesterone has been produced. Conidia of A. ochraceus also hydroxylate a variety of steroids. Spores of certain streptomycetes, phycomycetes (mucors), ascomycetes, and deuteromycetes are active. Most reactions already observed with vegetative cells have been repeated with spores. In general, spores of a particular organism effect fewer reactions than its mycelium, and fewer products accumulate.

ALDOSTERONE- AND CORTISOL SECRETION RATES IN INFANTS AND CHILDREN WITH CONGENITAL ADRENAL HYPERPLASIA SUGGESTING DIFFERENT 21-HYDROXYLATION DEFECTS IN "SALT-LOSERS" AND "NON SALT-LOSERS"

Aldosterone- and cortisol secretion rates were determined in nine infants and children with congenital adrenal hyperplasia (21-hydroxylation defects), three with the salt-losing type. Aldosterone secretion rates were determined before and after salt-deprivation for 4–6 days, using the double isotope dilution technique of Kliman & Peterson (1960). Cortisol secretion rates were determined before and on the third day of stimulation with ACTH-gel, 2 × 60 IU per day, using the method described by Cope & Black (1958).

Aldosterone secretion rates were normal in the »non salt-losers« (60–125 μg/24 h) and rose after salt-deprivation (100–380 μg/24 h). Extremely low values were found in the three patients with the salt-losing type (< 10 μg/24 h) and during salt-deprivation no increase was observed. Cortisol secretion rates before ACTH were in the normal range for all patients (4.2–34 mg/24 h; 12–33 mg/m2/24 h) except for one infant with the salt-losing type (< 0.5 mg/24 h). ACTH raised cortisol secretion rates in all »non salt-losers« (17–104 mg/24 h), but the increase was less than could be expected under normal conditions and the relative defect in the biosynthesis of cortisol was demonstrated in this way. Cortisol secretion rates after ACTH in the »salt-losers« were distinctly lower as compared with the »non salt-losers«.

»Salt-losing« and »non salt-losing« types of congenital adrenal hyperplasia as a result of 21-hydroxylation defects in the biosynthesis of cortisol and aldosterone represent two different genotypes. The results of these studies also suggest that both groups of patients represent biochemically two different types of the same disorder. This could be explained by two different genetically controlled changes in the 21-hydroxylation process, resulting in a different defect in the hydroxylation of progesterone and 17α-hydroxyprogesterone.

IATROGENIC ENDOMETRIAL PATTERNS

The histological patterns exhibited in the endometrium due to the newer progestational agents cannot be correlated with the patient's menstrual cycle or the physiological endometrium which follows ovulation. The oral progestational agents which have been produced during the past few years have had wide clinical application. Although the 19-nor-steroids and the derivatives of 17 alphahydroxyprogesterone differ in chemical structure, they produce similar histological appearances in the endometrium. Prolonged use of these compounds produces atrophy of the endometrial glands and a cellular stroma which might be mistaken for endometrial sarcoma. In view of the fact that such compounds are widely used in clinical practice and as contraceptive agents, it is essential that the pathologist should be aware of the bizarre endometrial patterns which they may produce; the more important of these changes are illustrated and discussed.

11 alpha-Hydroxylation of progesterone in biphasic media using alginate-entrapped Aspergillus ochraceus gel beads coated with polyurea

A novel cell-immobilization technique was developed in this study for increasing substrate partition to the gel matrix by coating a polyurea thin layer on the surface of Ca-alginate beads. The proposed method was simple and could be performed under mild conditions. The bioconversion of progesterone to 11 alpha-hydroxyprogesterone with these polyurea-coating alginate-entrapped Aspergillus ochraceus cells was investigated using different organic solvents in biphasic media. The reaction medium of ethyl acetate could markedly enhance the bioconversion rate with the existence of a hydrophobic layer, most likely resulting from the increasing partition of substrate to gel matrix. Bioconversion with higher substrate concentration was possible using an ethyl acetate-water medium. The conversion rate increased almost linearly with increasing substrate concentration from 10 to 80 g l-1. The rate with 80 g l-1 progesterone increased up to six times greater than the rate with the immobilized cells without coating, and also exhibited a much higher rate than that reported in the literature.

Affinity radiolabeling identifies peptides and amino acids associated with substrate binding in human placental 3 beta-hydroxy-delta(5)-steroid dehydrogenase

Purified human placental 3 beta-hydroxy-delta(5)-steroid dehydrogenase (3 beta-HSD) was affinity radiolabeled by 2 alpha-bromo[2'-14C]acetoxyprogesterone (2 alpha-BAP) in the presence or absence of 3 beta-HSD substrate, pregnenolone. The substrate steroid substantially protects 3 beta-HSD activity from inactivation by 2 alpha-BAP. Tryptic peptides of unprotected and substrate-protected radioalkylated enzyme were purified by high pressure liquid chromatography. The amino acid sequence of each radiolabeled peptide was determined and localized within the cDNA-derived primary structure of the enzyme. According to the percent total radioactivity associated with each of four radiolabeled peaks separated by high pressure liquid chromatography, two peptides were protected by substrate from affinity radioalkylation by 2 alpha-BAP. The first, 251GQFYYISDDTPHQSYDNLNYTLSK274, was produced by tryptic cleavage at Arg-250 and Lys-274 (the Arg-250 peptide) and contained radiolabeled His262. The second, 176NGGTLYTCALR186, was produced by tryptic cleavage at Lys-175 and Arg-186 (the Lys-175 peptide) and contained radiolabeled Cys183. Based on amino acid analysis to quantitate radioactivity incorporated per nmol of peptide, substrate steroid decreased the radiolabeling of His262 in the Arg-250 peptide by 3.6-fold and decreased the radiolabeling of Cys183 in the Lys-175 peptide by 3.7-fold. Three minor radiolabeled peptides (the NH2-terminal, Arg-71, and Arg-196 tryptic peptides) were also identified in the primary structure, but pregnenolone did not diminish their affinity radioalkylation. These observations indicate that the Arg-250 and Lys-175 peptides are involved in substrate binding and suggest that His262 and Cys183 are in close proximity in the three-dimensional structure of the enzyme.

Affinity labeling identifies histidine at the active site of human placental 3 beta-hydroxysteroid dehydrogenase and steroid 5-->4-ene-isomerase

OBJECTIVE

Our aim was to determine if the multifunction enzyme, 3 beta-hydroxysteroid dehydrogenase and steroid 5-->4-ene-isomerase has one or more active sites to effect dehydrogenase and isomerase activities.

STUDY DESIGN

This steroid, which we have purified to homogeneity from human placental microsomes, was inactivated by the affinity labeling steroid, 2 alpha-bromo[2'-14C]acetoxyprogesterone. The amino acids that were radioalkylated in the absence and presence of the dehydrogenase substrate pregnenolone were identified.

RESULTS

Pregnenolone completely abolished the inactivation of dehydrogenase. Histidine was localized in the active site of 3 beta-hydroxysteroid dehydrogenase because the radiolabel disappeared from enzyme inactivated in the presence of pregnenolone. Cysteine, a major radiolabeled product (80%) in the absence of pregnenolone, was decreased twofold in incubations that contained pregnenolone. Neither pregnenolone nor the isomerase substrate 5-androstene-3,17-dione protected isomerase from inactivation by the affinity alkylator.

CONCLUSION

This observation contradicts coexisting, separate binding sites, one for each activity. Rather, a conformation shift around one binding region prompted by products of the dehydrogenase reaction may create the isomerase activity.

Comparison of different antibody-conjugate derivatives for the development of a sensitive and specific progesterone assay

Antibodies raised against progesterone with hormone-carrier protein bridges placed at four different carbon positions were used to compare the sensitivity and specificity of homologous and heterologous enzyme-hormone conjugates. All heterologous assays were at least twice as sensitive as the corresponding homologous assays. The best results were obtained by using antibodies against 7 alpha-carboxyethyl-thioether-progesterone with 6 beta-hemisuccinate-progesterone conjugate (or hemimaleate). The sensitivity with human sera was 0.25 ng ml-1 and, the highest crossreaction 10% with 5 beta-pregnane-3,20-dione, and reproducibility, recovery and accuracy were satisfactory. The correlation coefficient with radioimmunoassay in 103 human sera tested was r = 0.915. The assay was successfully applied for the diagnosis of pregnancy in dairy cattle.

Corpus luteum function in successful in vitro fertilization cycles

The function of the corpus luteum in early pregnancy has been subject to some controversy. The purpose of our study was to determine the life span of the corpus luteum in early pregnancy after successful GnRH-a/hMG stimulation in IVF-ET. The study consisted of a retrospective analysis of patients after 12 successful singleton intrauterine IVF-ET cycles. Serum samples were obtained during early pregnancy beginning 14 days after hCG administration. The levels of 17 alpha-OHP, hCG, P, and E2 were measured in each sample. A significant negative correlation was noted between 17 alpha-OHP and date from hCG. The x-intercept of the regression line allowed estimation of the life span of the corpus luteum to be 72 +/- 25 days. In conclusion, in GnRH-a/hMG-stimulated IVF-ET cycles that result in a singleton pregnancy, the functional life span of the corpus luteum averages 72 days.

Steroid secretion of rainbow trout testis in vitro: variation during the reproductive cycle

Testicular tissue collected at different stages of gonadal development was incubated with a pituitary extract (PE) from mature salmon. Three androgens (11-ketotestosterone, OT; 11 beta-hydroxytestosterone, OHT; and testosterone, T) and 17 alpha,20 beta-dihydroxyprogesterone (17-20 beta P) were quantified by radioimmunoassay in incubation media. OHT and OT were secreted in larger quantities than T and 17-20 beta P. The PE dose that evoked a half-maximal response (ED50), the ratios of maximum stimulated vs baseline secretion, and total testicular steroid output all changed during the reproductive cycle. Androgen secretion in response to PE was low in immature and spent fish, both in terms of ED50 and the ratio of maximum stimulated vs baseline secretion. This ratio increased in testes showing the first signs of maturation and remained elevated during rapid testicular growth, before reaching maximum values at full maturity. The lowest ED50 values were found at the end of spermatogenesis and during the peak spawning period. 17-20 beta P secretion could not be stimulated noticeably until the fish had entered the spawning period and, as opposed to androgens, remained stimulable in spent fish. ED50 values for 17-20 beta P ranged, without showing clear-cut variations, above those calculated for androgens. The changes in PE reactivity and steroid secretion capacity during the reproductive cycle are likely to contribute to the changes in circulating steroid concentrations and may allow modulations of testicular steroid production without large changes in circulating GTH levels.

Effect of excipients on the stability of levothyroxine sodium tablets

Levothyroxine sodium tablets from two different manufacturers were analysed using the USP-NF method of analysis, a stability-indicating high pressure liquid chromatographic (HPLC) procedure. The results indicate that one particular manufacturer's 0.2-mg pink tablets contain some excipient(s) which act as a catalyst to hasten decomposition after extraction of levothyroxine for analysis. The same tablets from a different batch showed an additional long peak in the chromatogram, which indicated that the excipient(s) may have been changed. The same manufacturer has also used three different types of bottles/lids for the same product during the last year. Good manufacturing practice requires that new compatibilities/stability studies be conducted to assure the quality of the product. Ongoing stability studies are required by the Food and Drugs Administration (FDA). The use-life of 0.2-mg pink tablets of this manufacturer may be short.

Differing behavioral and endocrinological effects of two female sex pheromones on male goldfish

Ovulatory female goldfish sequentially release at least two sex pheromones: 17 alpha, 20 beta-dihydroxy-4-pregnen-3-one (17,20 beta P) and a mixture of F prostaglandins (PGFs). This study sought to determine whether these pheromones have different endocrinological and behavioral actions and whether the PGF pheromone, which is released by spawning females, is responsible for increasing the gonadotropin (GtH) and milt (sperm and seminal fluid) levels of spawning males. Grouped and isolated males were exposed to combinations of these pheromones, food odor, and spawning and nonspawning females. 17,20 beta P stimulated GtH increases in both grouped and isolated males but had only minor effects on behavior; because its principal function appears to be physiological it may be considered a "primer" pheromone. In contrast, exposue to the PGFs elicited large increases in sexual behavior but increased GtH only when fish were exposed as groups; this pheromone's principal action appears to be behavioral and it should be considered a "releaser" pheromone. Although males had increased GtH and milt levels after 1 hr of spawning, males allowed to interact with nonspawning females also had elevated GtH; thus, behavioral interactions appear capable of elevating GtH in the absence of either pheromone. The existence of an independent behavioral mechanism which stimulates GtH was supported by the fact that males exposed to 17,20 beta P while spawning had GtH levels much greater than males exposed to only one of these stimuli.

A comparison of alkaline phosphatase, beta-galactosidase, penicillinase and peroxidase used as labels for progesterone determination in milk by heterologous microtitre plate enzymeimmunoassay

Assays for alkaline phospatase, beta-galactosidase, penicillinase and peroxidase were optimised for quantitation in microtitre plate wells. Their value as labels in microtitre plate enzymeimmunoassay (EIA) for progesterone was assessed following coupling with 11 alpha-hydroxyprogesterone 11-glucuronide using an active ester procedure. Bridge-heterologous antiserum (11 alpha-hydroxyprogesterone 11-hemisuccinate-bovine serum albumin as immunogen) was used to minimize bridge recognition. The limits of detection of the enzymes were in the order penicillinase greater than peroxidase greater than alkaline phosphatase greater than beta-galactosidase. Under appropriate conditions it was possible to achieve greater than 50% displacement of label with 50 pg of progesterone for all four labels.

Use of progesterone 11-glucuronide-alkaline phosphatase conjugate in a sensitive microtitre-plate enzymeimmunoassay of progesterone in milk and its application to pregnancy testing in dairy cattle

A simple direct-addition microtitre plate enzymeimmunoassay (EIA) for progesterone in whole milk is described. The assay used antiserum raised against 11 alpha-hydroxyprogesterone 11-hemisuccinate (progesterone 11-hemisuccinate) and a heterologous label prepared by conjugation of 11 alpha-hydroxyprogesterone 11-glucuronide (progesterone 11-glucuronide) with alkaline phosphatase using an active ester procedure. The sensitivity, analytical recovery, linearity of response and precision of the assay compared favourably with radioimmunoassay (RIA). Results from EIA of milk samples were compared with determinations made after isolation of progesterone by HPLC (r = 0.910). Milk samples (200) were assayed by RIA at both the Milk Marketing Board and the Cattle Breeding Centre and the results were correlated with EIA performed at the Cattle Breeding Centre (r = 0.890 and r = 0.833 respectively). Calving data were obtained from a further 110 cows for which the milk progesterone EIA had provided a pregnancy test 24 days after AI; 46 cows were correctly identified as non-pregnant and 58 as pregnant and there were 4 false positive and 2 inconclusive results.

Fluorescent histochemical demonstration of estrogen and progesterone binding in giant cell tumors of bone: preliminary observations

Hormonal receptors of giant cell tumors (GCTs) have not been previously reported. Five cases of GCT of bone were analyzed for estrogen and progesterone binding. Frozen sections were studied by a histochemical method, using 17-beta-6-CMOBSA-FITC and 11-alpha-hydroxyprogesterone-HS-BSA-TMRITC. Cytoplasmic fluorescence with estradiol-BSA-FITC was seen in stromal cells of all five tumors; three also showed cytoplasmic staining with progesterone-BSA-TMRITC. No fluorescence was seen in the giant cells. Two cases were also analyzed by a dextran-coated charcoal cytosol assay. No estrogen or progesterone receptor was detected by cytosol assay. This study suggests that the estrogen and progesterone binding is present in GCT of bone, possible to low-affinity sites rather than high-affinity receptors. Further investigation of hormonal receptors of GCTs of bone is warranted.

"Dot-17 alpha-hydroxyprogesterone" radioimmunoassay for identification of congenital adrenal hyperplasia in young infants

Using a simplified radioimmunoassay method for the determination of 17-hydroxyprogesterone (17-OHP) concentration in blood dried on filter paper seven untreated cases of congenital adrenal hyperplasia were identified among newborns and infants at risk for congenital adrenal hyperplasia (CAH) having ambiguous genitalia and/or failure to thrive with electrolyte disturbances. In three additional cases the diagnosis of congenital adrenal hyperplasia was confirmed by high 'dot-17-OHP' values even after glucocorticoid therapy had been started. Capillary blood samples taken in a local hospital on a filter paper routinely used for the screening of phenylketonuria can be sent by mail into a central laboratory for performing the analysis. Assays of 'dot-17-OHP' are clearly of diagnostic value in the C21-hydroxylase form of CAH and permit a rapid diagnosis of this condition in the newborn period.

Steroid structure and function V. A-ring conformation in 17-hydroxy-6 alpha-methylprogesterone

The molecular conformation of 17-hydroxy-6 alpha-methylprogesterone has been determined crystallographically and is compared with 17-hydroxy-progesterone, 17-acetoxyprogesterone and 17-acetoxy-6 alpha-methylprogesterone (MPA). The analysis demonstrates that the 6 alpha-methyl substituent is not sufficient by itself to induce inversion of the A-ring. Consequently, the inverted form observed in MPA and proposed to be responsible for high affinity binding to the progesterone receptor appears to be induced by the combined long range influence of 17 alpha-acetoxy substituent and the direct interaction of the 6 alpha-methyl group with the flexible A-ring.

The activation of microsomal steroid 21-hydroxylase by cytosol from the cortex of bovine adrenals

At low microsome concentrations, the addition of cytosol from bovine adrenal cortex markedly accelerates the rate of hydroxylation of 17-hydroxyprogesterone at C-21. The detection of this effect was made possible by the development of a new, rapid, and sensitive procedure for the measurement of the initial rate kinetics of steroid 21-hydroxylase. This procedure is based on the fact that the reactant, 17-hydroxyprogesterone, possesses solvent partition properties which are different from those of the product, cortexolone. The specificity of the assay was confirmed by the isolation of only one product which was identified as cortexolone by radiochemical techniques. This assay procedure has great sensitivity and makes possible the accurate determination of the Michaelis constant at low enzyme concentrations. The Km for 17-hydroxyprogesterone with saturating amounts of TPNH was found to be 0.3 micronM. At the low microsome concentrations permitted by this assay, the addition of cytosol has a profound effect upon the rate of hydroxylation. The rate is markedly accelerated although the Km for the substrate is not altered. Neither the substrate nor the carbon monoxide-induced difference spectra are changed by the addition of cytosol, suggesting that activation by cytosol dose not affect the catalytic unit of the 21-hydroxylase complex.