Species specificity of radioreceptor assay and radioimmunoassay for rat FSH

Species specificity of the radioreceptor assay (RRA) for rat FSH, in which pregnant mare serum gonadotropin (PMSG)-treated immature rat ovary was employed as the receptor, was compared with that of NIAMDD rat FSH radioimmunoassay (RIA). In the RIA system, pituitary preparations from mammals only showed significant crossreaction. Their inhibition curves, however, were not always parallel to the standard curve. On the other hand, in the RRA system, the pituitary preparations from mammals, avians, lizard and amphibians competitively inhibited the binding of radioactive rat FSH to the ovarian receptor. Only the pituitary preparation from dog salmon failed to show any crossreaction in the RRA system. These results indicated that this RRA system would be useful for the measurement of FSH or gonadotropins of the pituitaries from mammals to amphibians.     

Internuclear control of DNA synthesis in exconjugant cells of Paramecium caudatum

An exconjugant cell of Paramecium caudatum has two kinds of macronuclei, fragmented prezygotic macronuclei and postzygotic new macronuclei (anlagen). Although the DNA synthesis in the fragmented prezygotic macronucleus continues until the third cell cycle after conjugation, selective suppression of the DNA synthesis in the prezygotic macronucleus takes place at the fourth cell cycle. The inhibition of DNA synthesis in prezygotic fragmented macronuclei is due to the presence of a postzygotic macronucleus (anlage) in the same cytoplasm because the inhibition does not occur when the postzygotic macronucleus (anlage) is removed by micromanipulation during the third or fourth cell cycle. Well-developed postzygotic macronuclei (anlagen) with full ability to divide have the ability to depress the DNA synthesis of prezygotic macronuclear fragments. The suppression of DNA synthesis in prezygotic macronuclear fragments seems to be irreversible. Competition for the limited amount of DNA precursors also plays an important role in the onset of the selective suppression of the DNA synthesis.     

A case of histiocytosis X associated with panhypopituitarism and hyperimmunoglobulinemia G and E.

A 43 year old man with diabetes insipidus who showed panhypopituitarism and marked hypergammaglobulinemia due to histiocytosis X is reported. His low basal plasma adrenocorticotropin (ACTH) and growth hormone (GH) failed to respond to insulin-induced hypoglycemia. His basal serum thyroid hormone level was below normal and normal basal plasma thyrotropin (TSH) showed a delayed response with normal peak value to TSH-releasing hormone (TRH). Normal basal plasma pituitary gonadotropin also showed a delayed response with normal peak value to luteinizing hormone-releasing hormone (LH-RH). Suppression of plasma prolactin (PRL) by levodopa (l-dopa) was impaired and elevation of basal plasma PRL was noted at the second admission. These results, combined with diabetes insipidus, suggested that the panhypopituitarism in these patients was hypothalamic in origin. The polyclonal hypergammaglobulinemia was characterized by elevated serum IgG and IgE levels which returned to normal after corticosteroid treatment with concomitant clinical improvement. Elevated serum IgE levels, tissue and peripheral eosinophilia, and the effectiveness of corticosteroid therapy support the hypothesis that some allergic mechanism may be involved in the pathogenesis of this disease.     

An increase of pituitary 3', 5' cyclic adenosine monophosphate produced by estradiol benzoate in vitro: possible implication of this increase in the secretion of luteinizing hormone.

In an attempt to study the site and mechanism of action of estrogen in producing positive feedback control, porcine anterior pituitary slices were incubated in vitro in the presence of estradiol benzoate (EB). EB elevated pituitary cyclic AMP concentration within 5 min and augmented pituitary release of luteinizing hormone (LH). The magnitude of increase of cyclic AMP and LH release was related to the doses of EB used. Also, luteinizing hormone releasing hormone (LH-RH) elevated pituitary cyclic AMP concentration and stimulated pituitary release of LH. The magnitude of increase of cyclic AMP and LH release was inversely related to the doses of LH-RH used. EB and LH-RH were additive in increasing cyclic AMP. Progesterone and clomiphene citrate interfered with an increase of pituitary cyclic AMP produced by EB, but did not significantly affect the basal level of pituitary cyclic AMP. Testosterone propionate, human chorionic gonadotropin and hexestrol were without effect on either basal or stimulated level of pituitary cyclic AMP. Since cyclic AMP and dibutyryl cyclic AMP (DBC) stimulated LH release, it is suggested that EB directly stimulates the release of LH by augmenting cyclic AMP synthesis in the anterior pituitary.     

Pumpkin (Cucurbita sp.) seed globulin I. Purification, characterization, and subunit structure

A heat stable globulin present in the cotyledons of pumpkinseeds was prepared as crystals which were soluble in a dilutesaline solution below pH 4.5 or in a solution with a high ionicstrength at neutral pHs. The protein was nearly homogeneousby ultracentrifuge analysis, and had a molecular weight of about112,000 daltons. Sodium dodecyl sulfate-polyacrylamide gel electrophoresisseparated the globulin into two subunits, and ß,corresponding to molecular weights of about 63,000 and 56,000daltons, respectively. By reduction of disulfide bonds, thetwo subunits were each separated into two polypeptide chainswith molecular weights of around 36,000 and 22,000 daltons,judged by gel electrophoresis. The amino acid composition ofwhole globulin indicated high contents of arginine, glutamicacid and aspartic acid. The total number of half-cystine residuewas nine and only one residue was shown to be free. The subunitstructure of the globulin is discussed. The protein has beenshown to have oxaloacetate decarboxylase activity, and thisfact was confirmed. However, the activity decreased markedlyat pH 4.5 in a fairly short period. It did not require Mn⁺⁺,and the K_m for oxaloacetate was determined to be 4.1 mM. (Received April 9, 1976; )     

Effects of x-ray irradiation on the subsequent gonadotropin secretion in normal and neonatally estrogenized female rats.

Female rats were irradiated with 190R of X-rays at 10 days of age and sacrificed 4, 7 or 12 months later. Their ovaries were histologically examined and serum levels and pituitary contents of luteinizing hormone (LH) and follicle-stimulating hormone (FSH) were determined by radioimmunoassay. Both serum levels and pituitary contents of LH and FSH rose significantly 4 and 7 months after irradiation, although the ovaries were markedly reduced in weight. On the contrary, 12 months after irradiation, the ovaries increased in weight and consisted mostly of polyhedral, hyperplastic interstitial cell masses, and both LH and FSH in the serum and pituitary were reduced to normal levels. These characteristic changes in the ovarian weight and histological appearance could not be observed in the similarly irradiated animals which were received daily injections of estrone for the first 30 days of postnatal life, i.e., daily injections of 50 mug for the first 10 days, 100 mug for the middle 10 days and 200 mug for the last 10 days. Serum LH levels of the estrogenized irradiated rats at 7 or 12 months of age did not elevate although those of FSH were significantly higher than the non-irradiated intact levels. From these results, a rise in the blood levels of LH and the FSH may be attributed to the increase in weight and the histological changes in the ovaries of the irradiated female rats, and the elevation of only FSh level may not result in the abnormal growth of the irradiated ovaries.     

Effects of rosuvastatin on electronegative LDL as characterized by capillary isotachophoresis: the ROSARY Study

Electronegative LDL, a charge-modified LDL (cm-LDL) subfraction that is more negatively charged than normal LDL, has been shown to be inflammatory. We previously showed that pravastatin and simvastatin reduced the electronegative LDL subfraction, fast-migrating LDL (fLDL), as analyzed by capillary isotachophoresis (cITP). The present study examined the effects of rosuvastatin on the more electronegative LDL subfraction, very-fast-migrating LDL (vfLDL), and small, dense charge-modified LDL (sd-cm-LDL) subfractions. Patients with hypercholesterolemia or those who were being treated with statins (n = 81) were treated with or switched to 2.5 mg/d rosuvastatin for 3 months. Rosuvastatin treatment effectively reduced cITP cm-LDL subfractions of LDL (vfLDL and fLDL) or sdLDL (sd-vfLDL and sd-fLDL), which were closely related to each other but were different from the normal subfraction of LDL [slow-migrating LDL (sLDL)] or sdLDL (sd-sLDL) in their relation to the levels of remnant-like particle cholesterol (RLP-C), apolipoprotein (apo) C-II, and apoE. The percent changes in cm-LDL or sd-cm-LDL caused by rosuvastatin were correlated with those in the particle concentrations of LDL or sdLDL measured as LDL-apoB or sdLDL-apoB and the levels of HDL-C, RLP-C, apoC-II, and apoE. In conclusion, rosuvastatin effectively reduced both the vfLDL subfraction and sd-cm-LDL subfractions as analyzed by cITP.