Browsing by Author "Ampuero, S"

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    Bioactivity of prolactin isoforms
    (1999) Campino, C; Torres, C; Ampuero, S; Díaz, S; González, GB; Serón-Ferré, M
    To assess whether plasma prolactin (PRL) characteristics relate to lactogenesis and absence or presence of menstrual cycles, we measured bioactive PRL (BIO;PRL) using the Nb2 assay, immunoreactive PRL (TR-PRL) by radioimmunoassay, calculated equations describing the BIO-PRL-IR-PRL relationship and separated charged PIiL isoforms (by chromatofocusing) in five amenorrhoeic and five cycling nursing women at 6 months postpartum and in 10 cycling non-nursing women, Plasma samples were drawn before and 30 min after a suckling episode at 0800, 1600 and 2400 h in nursing women and at the same hours ih non-nursing women. BIO-PRL and IR-PRL concentrations were highest in amenorrhoeic nursing women, intermediate in cycling nursing women and lowest in cycling non-nursing women. The BIO-PRL-IR-PRL relationship shows that a given amount of IR-PRL corresponds to equivalent amounts of BIO-PRL in cycling nursing and cycling nonnursing women, and to a larger extent in amenorrhoeic nursing women. IR-PRL was present In plasma as several charge isoforms, Bioactive isoforms eluting at PH 6.0-5.1 were found in amenorrhoeic and cycling nursing women, reaching similar concentrations after suckling. Bioactive isoforms eluting at pH 7.0-6.1 were found only in amenorrhoeic nursing women. We speculate that isoforms eluting at pH 6.0-5.1 may play a role in lactation and isoforms eluting at pH 7.0-6.1, in lactational amenorrhoea.
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    Post-suckling prolactin:oestradiol ratio - a potential index to predict the duration of lactational amenorrhoea in women
    (1997) Campino, C; Ampuero, S; Diaz, S; Lopez, JM; SeronFerre, M
    To assess whether the duration of lactational amenorrhoea can be predicted in individual women, we studied the pre-and post-suckling concentrations of immune prolactin (IR-PRL) and of bioactive prolactin (BIO-PRL) and basal concentrations of oestradiol in ten amenorrhoeic fully nursing women at 3 months post-partum. The women were of similar age, weight and had infants of similar growth rate, Five of these women were to experience long amenorrhoea (>180 days) and the others short amenorrhoea (<180 days), Blood samples were drawn 30 min after a suckling episode initiated at 0800 h, 1600 h and 2400 h. BIO-PRL distinguished between groups of women at 0030 h but not at other times, while there was considerable overlap between values for IR-PRL and oestradiol at all times studied, At 1630 h, the ratios post-suckling BIO-PRL: oestradiol and post-suckling IR-PRL:oestradiol were above 2000 in the women that were to experience long amenorrhoea and below this threshold in the other women, The ratio post-suckling BIO-PRL:oestradiol provided more information since the difference between the lowest ratio in the long amenorrhoea and the highest ratio in the short was 699, while it was 520 for the IR-PRL:oestradiol ratio, The determination of these ratios may help to predict the duration of lactational amenorrhoea in individual fully nursing women.