Verónica Ambao

Publications (3)11.55 Total impact

• Source

  Available from: María Eugenia Matzkin

  Article: Prolactin (PRL) induction of cyclooxygenase 2 (COX2) expression and prostaglandin (PG) production in hamster Leydig cells.

  María Eugenia Matzkin, Verónica Ambao, Mónica Herminia Carino, Soledad Paola Rossi, Lorena González, Daniel Turyn, Stella Campo, Ricardo Saúl Calandra, Mónica Beatriz Frungieri
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  ABSTRACT: Serum prolactin (PRL) variations play a crucial role in the photoperiodic-induced testicular regression-recrudescence transition in hamsters. We have previously shown that cyclooxygenase 2 (COX2), a key enzyme in the biosynthesis of prostaglandins (PGs), is expressed mostly in Leydig cells of reproductively active hamsters with considerable circulating and pituitary levels of PRL. In this study, we describe a stimulatory effect of PRL on COX2/PGs in hamster Leydig cells, which is mediated by IL-1β and prevented by P38-MAPK and JAK2 inhibitors. Furthermore, by preparative isoelectric focusing (IEF), we isolated PRL charge analogues from pituitaries of active [isoelectric points (pI): 5.16, 4.61, and 4.34] and regressed (pI: 5.44) hamsters. More acidic PRL charge analogues strongly induced COX2 expression, while less acidic ones had no effect. Our studies suggest that PRL induces COX2/PGs in hamster Leydig cells through IL-1β and activation of P38-MAPK and JAK2. PRL microheterogeneity detected in active/inactive hamsters may be responsible for the photoperiodic variations of COX2 expression in Leydig cells.
  Molecular and Cellular Endocrinology 07/2011; 348(1):33-46. · 4.19 Impact Factor
• Source

  Available from: Marta Tesone

  Article: Regulation of inhibin/activin expression in rat early antral follicles.

  Luz Andreone, Ethel V Velásquez, Dalhia Abramovich, Verónica Ambao, Nazareth Loreti, Horacio B Croxatto, Fernanda Parborell, Marta Tesone, Stella Campo
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  ABSTRACT: The aim of the present study was to determine the endocrine activity of cultured early antral follicles (EAF) isolated from prepubertal diethylstilbestrol-treated rats. The effect of steroidogenic substrates and FSH on steroid, inhibin A and B, Pro-alphaC and activin A production was evaluated. Androsterone was the predominant steroid produced by EAF. The addition of androstenedione, androstenedione+FSH and progesterone stimulated oestradiol production, whereas 25-hydroxycholesterol (25-OH-Chol) increased progesterone production. Inhibin A, B, Pro-alphaC, and activin A were produced under basal conditions. The predominance of inhibin B over inhibin A was not affected by the addition of androstenedione or progesterone. Inhibin A and activin A production was stimulated by FSH. 25-OH-Chol increased Inha, Inhba and Inhbb mRNA expression and the production of the three molecular forms of inhibins but decreased activin A production. These results show that FSH and the steroid follicular microenvironment differentially modulate the gene expression of inhibin/activin subunits, their assembly and secretion.
  Molecular and Cellular Endocrinology 06/2009; 309(1-2):48-54. · 4.19 Impact Factor
• Article: Carbohydrate complexity and proportion of serum FSH isoforms reflect pituitary-ovarian activity in perimenopausal women and depot medroxyprogesterone acetate users.

  Nazareth Loreti, Verónica Ambao, Cassia Teatin Juliato, Cecilia Machado, Luis Bahamondes, Stella Campo
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  ABSTRACT: FSH is synthesized and secreted in multiple glycosylation variants with different oligosaccharide structures; the endocrine milieu regulates the composition of FSH carbohydrate moiety. To characterize serum FSH isoforms according to their sialic acid content and oligosaccharide complexity in regularly menstruating women and in depot medroxyprogesterone acetate (DMPA) users during the menopausal transition. Subjects and methods Ten regularly menstruating perimenopausal women aged 45-52, with mid-follicular phase FSH levels < or =10 IU/l and 10 regularly menstruating women, aged 20-39, were included. Blood samples were collected on the ninth day of the menstrual cycle. Twenty DMPA users were divided into two groups (n = 10) according to age: DMPA(1), age range 20-39 and DMPA(2), age range 45-52. Blood samples were collected 90 +/- 5 days after the last injection of DMPA. Oestradiol (E(2)), inhibin B (Inh B), Pro-alphaC levels and the relative abundance of FSH isoforms on the basis of charge (preparative isoelectric focusing) and carbohydrate complexity (Concanavalin A chromatography) were determined. Decreased Inh B and moderately elevated E(2) levels were observed in perimenopausal women associated with an increase in FSH sialylation and a decrease in its oligosaccharide complexity. DMPA induced changes in the hormonal profile and FSH molecular microheterogeneity; the secreted hormone was more heterogeneous and its oligosaccharides were less complex under this condition. Serum FSH glycoforms with increased sialylation and decreased oligosaccharide complexity reflect the decline of the gonadal activity induced either by age or by the use of a DMPA as a contraceptive.
  Clinical Endocrinology 02/2009; 71(4):558-65. · 3.17 Impact Factor