Browsing by Author "Díaz, 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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    Norplant® implants and progesterone vaginal rings do not affect maternal bone turnover and density during lactation and after weaning
    (1999) Díaz, S; Reyes, MV; Zepeda, A; González, GB; López, JM; Campino, C; Croxatto, HB
    Bone density and turnover was assessed in a longitudinal study of healthy lactating women who initiated use of Norplant(R) implants (NOR, n = 29), progesterone vaginal rings (PVR, n = 28) or Copper T 380A intrauterine devices (T-Cu, n = 51, control group) around day 60 postpartum. Bone density, serum calcium, phosphorus, alkaline phosphatases, parathyroid hormone (PTH), follicle stimulating hormone (FSH), oestradiol and prolactin, and urinary hydroxyproline and creatinine were measured at postpartum months 1 (PM1), and 12 (PM12) and 6 or 12 months after weaning; at month 6 postpartum (PM6) serum and urine tests alone were performed. Baseline characteristics and lactation performance were similar between groups. Biochemical markers of bone turnover were higher at PM1, PM6 and PM12 than after weaning, with no differences between groups. Bone density in the lumbar spine (L2-L4) and femoral neck at PM1 and PM12 (similar to 1.11 g/cm(2)) was similar in three groups. Lumbar spine values were found to be lower in lactating women than those present in nonlactating women, but increased after weaning to similar values, The two progestin-only contraceptives studied appear to have no deleterious effect upon bone density and metabolism in healthy lactating women.