Stereoselectivity of a radioimmunoassay for the insecticide S-bioallethrin

Summary The stereoselectivity of a radioimmunoassay (RIA) system using an S-bioallethrin specific antiserum was studied by observing the abilities of the 8 allethrin isomers and other selected compounds to compete with a radiolabelled S-bioallethrin tyramine derivative for antibody binding sites. The results demonstrate the feasibility of RIA as a rapid, sensitive and stereoselective residue technique for compounds difficult to analyze by classical methods.This work was supported in part by grant No. 5-R01-ES01260-02 from the National Institutes of Health.     

Comparison of intradermal pigeon crop-sac bioassay and double antibody radioimmunoassay for rat prolactin

Summary On an absolute basis, the intradermal pigeon crop-sac bioassay (PCA) gave results that were 20.5% higher than the radioimmunoassay (RIA) in rat anterior pituitary (AP) preparations. A highly significant correlation (r=0.87) was obtained between RIA (in g) and PCA (in Reece-Turner units) when 58 medium samples obtained by culturing rat APs in vitro were assayed for prolactin (PRL) content.Supported by the Charles and Johanna Busch Memorial Fund and by Hatch Amended Funds, Rutgers University-The State University of New Jersey, New Brunswick, NJ 08903, USA.The authors acknowledge the generous supply of rat PRL reference preparation and iodination material for the RIA by NIAMDD, NIH.     

Use of three specific radioimmunoassays in measuring neurohypophysial hormone content and plasma concentrations of vasopressin, oxytocin and DDAVP in rats after prolonged infusion of DDAVP

Specific radioimmunoassays (RIA) were employed for measuring plasma and neurohypophysial concentrations of oxytocin (OT) and vasopressin (AVP) after administration of 1-deamino-8-D-Arg-vasopressin (DDAVP). DDAVP concentrations were measured by a newly-developed specific RIA. Through the use of minipumps, DDAVP was infused i.p. over a period of 3 days in normally hydrated rats. Despite decreased urine production and increased urine osmolality no changes could be observed in neurohypophysial and plasma hormone concentrations.     

Use of three specific radioimmunoassays in measuring neurohypophysial hormone content and plasma concentrations of vasopressin,oxytocin and DDAVP in rats after prolonged infusion of DDAVP

Summary Specific radioimmunoassays (RIA) were employed for measuring plasma and neurohypophysial concentrations of oxytocin (OT) and vasopressin (AVP) after administration of 1-deamino-8-D-Arg-vasopressin (DDAVP). DDAVP concentrations were measured by a newly-developed specific RIA. Through the use of minipumps, DDAVP was infused i.p. over a period of 3 days in normally hydrated rats. Despite decreased urine production and increased urine osmolality no changes could be observed in neurohypophysial and plasma hormone concentrations.     

Changes in ecdysone levels in the spiderPisaura mirabilis nymphs (Araneae,Pisauridae)

Summary RIA of ecdysones are made on nymphal extracts ofPisaura mirabilis during the intermoulting cycle. The hormone level is low during exuviation and the greatest part of the intermoulting period but increases notably before and after ecdysis. The main hormonal peak or pre-ecdysial peak is due to -ecdysone, characterized by combined TLC/RIA.Acknowledgment. We wish to thank Dr M. Hirn for his help during the manipulations and J. Britton who has translated the text into English.     

Self-labeling of human polymorphonuclear leucocyte myeloperoxidase with 125iodine.

In order to obtain a radioimmunoassay (RIA) technique for the measurement of human plasma myeloperoxidase (MPO), we purified the enzyme from polymorphonuclear granulocytes (neutrophils), and compared three methods of labeling it with 125Iodine:chloramine T, lactoperoxidase, and an original technique of 'self labeling' based on the ability of the enzyme to oxidize and bind 125I in the presence of H2O2. The chloramine T technique produced a degraded protein, as well shown by a high non-specific binding of tracer to antibody. The lactoperoxidase technique did not succeed in labeling MPO with an adequate specific activity. In contrast, the self-labeling method gave a stable tracer with a specific activity of 23 microCi/micrograms MPO (85 MBq), a satisfactory level of immunoreactivity, and a low-specific binding (less than or equal to 3%). After labeling, purification of tracer was achieved by gel filtration chromatography in phosphate buffer (0.05 M; pH7) to which 0.1% poly-L-lysine was added. The labeled molecule remained stable for 40 days and could be used for RIA with a polyclonal antibody raised in rabbits.     

Hormonal control of manganese transport in the mouse thyroid.

The present study deals with a possible mechanism controlling the transport of manganese (Mn), an essential trace element, from the circulation to the thyroid. Mice were pretreated with propylthiouracil (PTU) or triiodothyronine (T3), and a measurement of the thyroid:serum concentration ratio (T/S) of radioactive manganese (54Mn) was carried out. The T/S of 54Mn was greatly enhanced by PTU, but reduced by T3. Several methods were used to demonstrate that the T/S of 54Mn depends upon the level of thyroid-stimulating hormone (TSH) in the serum. First, bovine TSH was injected into mice; an increase in the T/S resulted. Secondly, serum thyroxine and T3 levels measured by radioimmunoassay (RIA) suggested that PTU produced an increase in serum TSH and T3 a decrease. However, direct measurement of mouse TSH by RIA for rat TSH failed to produce proof of any changes in TSH level, owing to poor cross-reactivity. Taking all the information into account, it is concluded that Mn-transport into the thyroid is controlled by the thyroid state.     

Occurrence of 3-epi-22-deoxy-20-hydroxyecdysone and its phosphoric ester in diapause eggs of the silkworm,Bombyx mori

Ecdysteroids in diapause eggs of the silkworm,Bombyx mori, were analyzed using high-performance liquid chromatography (HPLC) combined with radioimmunoassay (RIA). A relatively large amount of an unidentified free ecdysteroid and its phosphoric ester (conjugated form) were detected. These two compounds were isolated by a combination of column chromatography on silicic acid, thin-layer chromatography (TLC), and HPLC using a reverse-phase (RP) column. The purified compounds were identified as 3-epi-22-deoxy-20-hydroxyecdysone (22d20E) and 3-epi-22-deoxy-20-hydroxyecdysone 2-phosphate (22d20E2P) by means of mass spectrometry and nuclear magnetic resonance spectroscopy. to our knowledge, this is the first report of 22d20E and 22d20E2P.     

Radioimmunoassay of an invertebrate peptide hormone - the crustacean neurosecretory hyperglycemic hormone.

Antibodies against hyperglycemic hormone (CHH) of Carcinus were raised in rabbits by injection of extract from sinus glands which contain high concentrations of CHH. The antiserum neutralizes the biological activity of CHH and binds 125-J-CHH. A RIA for CHH was established and was used to measure the hormone content of sinus glands.     

Hormonal control of manganese transport in the mouse thyroid

The present study deals with a possible mechanism controlling the transport of manganese (Mn), an essential trace element, from the circulation to the thyroid. Mice were pretreated with propylthiouracil (PTU) or triiodothyronine (T₃), and a measurement of the thyroid:serum concentration ratio (T/S) of radioactive manganese (⁵⁴Mn) was carried out. The T/S of⁵⁴Mn was greatly enhanced by PTU, but reduced by T₃. Several methods were used to demonstrate that the T/S of⁵⁴Mn depends upon the level of thyroid-stimulating hormone (TSH) in the serum. First, bovine TSH was injected into mice; an increase in the T/S resulted. Secondly, serum thyroxine and T₃ levels measured by radioimmunoassay (RIA) suggested that PTU produced an increase in serum TSH and T₃ a decrease. However, direct measurement of mouse TSH by RIA for rat TSH failed to produce proof of any changes in TSH level, owing to poor cross-reactivity. Taking all the information into account, it is concluded that Mn-transport into the thyroid is controlled by the thyroid state.     

Inhibition of hypothalamic GnRH synthesis by inhibin

Summary Both testicular and ovarian inhibin preparations blocked GnRH synthesis by the hypothalamus and consequently reduced the circulating level of FSH. The serum level of LH was unaffected.Acknowledgment. We thank Dr S. Raiti of NIAMDD, National Institutes of Health, Bethesda, USA, for rat-hormone assay kits and Ms Maria Enrica Mongardi of Instituto Farmacologico Serono, Italy, for GnRH RIA kit.     

Composition and efficacy of iodothyronine immunogens and host responsiveness in radioimmunoassay (RIA) for serum thyroxine (T4)

Summary An immunogen was prepared consisting of iodinated and thyroxylated bovine thyroglobulin which on theoretical and practical grouds was highly specific for thyroxine; a rabbit antiserum derived from it fell within limits for RIA specification under conditions wherein a T4-BSA immunogen product was inactive.     

The effects of continuous chloroform and halothane anesthesia on plasma prolactin levels in ovariectomized estrogen-treated rats

Summary In ovariectomized, estrogen-treated rats bearing indwelling aortic catheters, continuous inhalation of chloroform or halothane resulted in increases in plasma prolactin levels 10 min after the exposure to the anesthetics. The plasma prolactin levels over the subsequent 2 h, however, were not significantly different from that of the control animals.Supported by NSF Research Grant BMS 74-17332.The authors wish to express their appreciation to Mrs Cynthia Van De Walle for her outstanding assistance in the performance of the prolactin RIA and the art work.     

The lack of an effect of cholinergic agonists on anterior pituitary prolactin production in vitro

Summary The addition of dopamine to anterior pituitary incubations resulted in a marked decrease (88% for³H prolactin and 69% for RIA prolactin) in prolactin release. Incubation with the cholinergic agonists carbacol, arecoline and nicotine resulted in no significant change in prolactin secretion.Supported in part by NSF Research grant No. BMS 74-17332.The authors appreciate receiving as a gift from the National Institute of Arthritis, Metabolic and Digestive Diseases, the rat prolactin used for iodination (RP-I₂) and standards (RP-1).     

Influence of dopamine infusion on plasma prolactin released by kidney capsule transplanted anterior pituitaries

Summary The infusion of dopamine into the renal artery resulted in decreased prolactin release from 3 anterior pituitary glands transplanted under the kidney capsule. Prolactin levels continually decreased over a 5 min period after DA infusion was terminated and thereafter approached preinfusion levels by the end of 10 min.Supported by NSF Research, grant No. 74-17332.The authors wish to express their appreciation to Mrs Cynthia Van De Walle for her outstanding technical assistance in the performance of the prolactin RIA and the statistical analyses. We also appreciate receiving as a gift from the National Institute for Arthritis, Metabolism and Digestive Diseases the rat prolactin used for iodination (RP-I₂) and standards (RP-1).     

Exogenous makisterone A accelerates early embryonic development in the milkweed bugOncopeltus fasciatus

Summary Reproducing females ofOncopeltus fasciatus which were treated with exogenous makisterone A and 20-hydroxyecdysone laid eggs with considerably elevated ecdysteroid contents. The early embryonic development was markedly accelerated when the mother was treated with makisterone A, whereas 20-hydroxyecdysone had no influence.Supported by grants of the Deutsche Forschungsgemeinschaft (Do 163/7) to A. D.The technical assistance of Ms Heike Bender is acknowledged. We thank Dr K.-D. Spindler for providing us with antiserum for the RIA.     

Ecdysteroids inLimulus larvae

Summary Free ecdysteroids were extracted from intermolt and premolt larvae ofLimulus polyphemus in the first posthatch stage, purified by TLC and HRLC, and assayed by RIA and theLimulus bioassay 20-hydroxyecdysone appears to be a principal ecdysteroid and occurs at least 3 times higher a concentration in premolt vs intermolt animals.Supported by NSF grant GB-40620.Acknowledgments. We are indebted to Prof. G. R. Wyatt for the antibody, Prof. K. Nakanishi for use of his laboratory for HRLC separations, and to Dr David King for the³H-ecdysone and for performing radio-TLC analyses.     

Plasma steroid and protein hormone concentrations in patients with benign prostatic hypertrophy and in normal men.

Serum levels of testosterone, FSH, LH and prolactin were measured by RIA in patients with BPH (benign prostatic hypertrophy) and in control men. The testosterone concentrations in the BPH group were significantly lower than that of the control group. Serum concentrations of FSH, LH, prolactin and estradiol, did not differ significantly in the 2 groups.     

Plasma steroid and protein hormone concentrations in patients with benign prostatic hypertrophy and in normal men

Summary Serum levels of testosterone, FSH, LH and prolactin were measured by RIA in patients with BPH (benign prostatic hypertrophy) and in control men. The testosterone concentrations in the BPH group were significantly lower than that of the control group. Serum concentrations of FSH, LH, prolactin and estradiol, did not differ significantly in the 2 groups.     

Release of immuno-reactive and biologically active LH from fetal mouse pituitary in response to synthetic gonadotropin releasing factor (LRF).

In an incubation system, LRF stimulated significantly the release of LH from 18-day-old mouse fetal pituitary. This LRF-induced LH release, measured by RIA in the incubation medium was able to increase the testosterone production by age-matched fetal testes. This data suggests that the hypothalamo-hypophyseal-testicular axis is functional at the end of mouse prenatal life.