Size heterogeneity and specific binding property of immunoreactive prolactin in human seminal plasma

Following gel filtration on a Sephadex G-100 column, and radioimmunoassay of the effluent fractions, seminal plasma samples from fertile men appeared to possess three discrete immunoreactive prolactin (IR-Prl) components analogous to those of normal serum and pituitary extract and an additional minor component which was eluted after ribonuclease. Furthermore, IR-Prl seminal plasma was predominantly recovered from the column in the high molecular size region, while in the serum and pituitary extract much of the activity was coeluted with monomeric hPrl (purified). Rechromatography of IR-Prl components in seminal plasma provided no evidence of the conversion of one component into the other. Examination of these different components of IR-Prl by means of radioreceptor assay (RRA) indicated that the highly retarded component exhibited no RRA activity. The other three components differed in their drgrees of RRA activity

Purification of prolactin binding protein from rat seminal vesicle secretion

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Evidence for the presence of specific prolactin binding protein in rat seminal vesicle fluid

The presence of a specific prolactin binding in rat seminal vesicle fluid has been demonstrated. The binding phenomenon was saturable and pH dependent, the optimum pH being 7.2. The prolactin binding protein (PBP, 1800 × g supernatant) was characterized by a single order affinity binding sites with an association constant (Ka) 1.52 × 10(7) mol-1. The specificity of the prolactin binding was demonstrated by the fact that other proteohormones such as rFSH, rLH, rTSH and hTSH failed to inhibit the binding of labelled hormone to PBP, while unlabelled oPRL gave a dose-response inhibition curve. Among the rats in the age group 45 to 180 days, PBP obtained from animals of 90 day old showed a maximum binding of radioiodinated rPRL. Following castration for five days the percent binding of 125-I-rPRL to PBP decreased markedly. The treatment of castrated rats with testosterone propionate for five days returned the 125-I-rPRL binding to near intact values. Following a centrifugation of 1800 × g supernatant at 360 000 × g for 3 h, prolactin binding activity still remained in the supernatant thus implicating that the binding protein is in a soluble state

Changes in the ratio between serum and "specific" levels of human chorionic gonadotropin in different trimesters of pregnancy

Sixty-one sera from different trimesters of pregnancy were analyzed by two 125-I-NIH-HCG assay systems, employing anti-intact HCG serum and anti θ-HCG serum, respectively. The ratios of the levels measured in the two assay systems changed with the duration of pregnancy. The ratios during trimesters 1,2, and 3 were 2.94, 1.99, and 2.37, respectively. The cross-reactivity of proteohormones other than HCG was tested in both the assay systems. The two assay systems could be comparable in their high degree of specificity. However, the relative affinities of intact HCG and θ-HCG in the two assay systems were observed to be different. It was suggested that the significant differences in the ratios of the levels measured by the tow assay systems might have been infulenced by the occurrence of θ-HCG in serum and that the levels of the subunit must have changed at different stages of pregnancy

Nature of cross-reaction between hCG and anti-oLH serum and development of a radioimmunoassay to measure hLH specifically in the presence of hCG

Immunological cross-reaction between hCG and anti-oLH sera has been demonstrated using radioimmunoassay techniques. The results indicate that this cross-reaction is incomplete and that the anti-oLH sera used have the ability to distinguish between LH and hCG. Following absorption with purified hCG, anti-oLH serum was used to develop a heterologous radioimmunoassay "[125I]iodo-hLH + anti-oLH serum" (H-O, RIA) which specifically and selectively measures hLH in serum samples containing both hLH and hCG. In this radioimmunoassay, hCG and subunits of hCG do not cross-react with hLH, in the range in which these hormones are present in human serum under physiological conditions. Other hormones such as hPL, hPRL, hGH, hFSH, hTSH, and GnRH do not interfere with the measurement of LH by radioimmunoassay. The sensitivity of the assay was 1.5 mlU (25 ng) per ml (LER 907 standard), and the inter- and intra-assay coefficients of variations for samples were 10.83% and 8.4%, respectively. The recoveries of hLH added to pregnancy serum containing an hCG concentration of 8.55 IU\ml were in the range 95-108%. Determination of LH content of human pituitary extracts by H - 0 RIA gave values which were in close agreement with those derived by bioassay (indices of discrimination 0.72-1.12). Serum LH patterns in women during normal menstrual cycles as well as in amenorrheic patients who received GnRH treatment are comparable to those reported by other investigators using other radioimmunoassay systems. Serum samples obtained during the first trimester of pregnancy, when analyzed by H - 0 RIA, showed basal LH levels

Gonadotrophins during second trimester of pregnancy: I. LH and hCG levels in maternal serum and amniotic fluid and their relationship to the sex of the foetus

Luteinizing hormone and chorionic gonadotrophin levels were selectively measured by using radioimmunoassays in 98 maternal sera and 116 amniotic fluid samples obtained during 10-20 weeks of pregnancy. Levels of hCG in serum were clearly high during 10-14 weeks and thereafter declined gradually. In contrast, serum concentrations of LH during 10-20 weeks were either unmeasurable (< 1 ng/ml) or lower than those observed during the luteal phase of the menstrual cycle suggesting a decreased responsiveness of pituitary and/or a higher clearance rate for LH during this period of pregnancy. Neither LH nor hCG levels in maternal sera showed significant differences between male and female foetus bearers. A striking similarity was observed between maternal serum and amniotic fluid hCG patterns, despite hCG levels in maternal sera being always higher (1.5-26.9 fold). On the other hand amniotic fluid concentrations of LH became elevated following 12 weeks of gestation while maternal serum LH continued to be at low levels until 20 weeks. Furthermore a sexual dichotomy was observed in amniotic fluid LH concentrations but not in hCG levels during 14-20 weeks of pregnancy, with significantly lower LH levels in male foetus bearers than in female foetus bearers. Of interest is the clear demarcation in LH levels at 16 weeks of gestation. This sequential pattern of change in the concentrations of amniotic fluid LH is similar to those patterns reported by other investigators for foetal serum and pituitary LH during 10-20 weeks of gestation suggesting that the foetus may be the source of the increased levels of LH in amniotic fluid following 12 weeks of pregnancy

Synergistic action of prolactin with HCG on rat ventral prostate

The increase in the weights of the ventral prostate and other accessory sex organs of the immature rat has been employed as an end point for estimating the biological potency of preparations of LH and HCG (Greep et al., 1941, 1942; Diczfalusy & Loraine, 1955). Several investigators have claimed that prolactin alone or synergistically with androgens has a role in the growth of the male accessory sex organs (Segaloff et al., 1956; Chase et al., 1957; Antliff et al., 1960; Bengmark & Hesselsjo, 1963, 1964; Okamoto et al., 1967; Dorfman, 1972; Negro-Vilar et al., 1973). In these studies, large amounts of prolactin were used, and the possible presence of small amounts of contaminating LH could not be ruled out

Isolation & characterization of inhibin from human seminal plasma

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