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F Larrea

Publications and source records attributed to F Larrea.

84 records · Page 5Linked to original sources
PubMedDate not supplied

[Prolactin variants in serum and amniotic fluid of women with ovulatory hyperprolactinemia].

There is enough evidence that prolactin (PRL), like many other pituitary hormones, is composed by multiple forms that differ from each other by size charge. Although they can be seen in the pituitary glands of a variety of species, their biological significance, identity and chemical nature still remain poorly understood. Recently, a new syndrome characterized by normal ovarian function in the presence of sustained hyperprolactinemia has been reported by our group. In these women, highly abnormal percentages of serum big big PRL have been consistently demonstrated. This observation suggests that big big PRL is immunologically similar, but biologically less active than monomeric or little PRL. In this study we have determined then molecular size heterogeneity of immunoreactive PRL in serum and amniotic fluid from two ovulatory hyperprolactinemic subjects (subjects A and B) who had, under non-pregnant conditions, large amounts of serum big big PRL, throughout different stages of parturition. Control subjects consisted of two women at the end of pregnancy in whom PRL species demonstrated a normal size distribution (subjects C and D). Mean basal levels of PRL were the highest in subjects A and B and remained constant during labor. In the control subjects a remarkable decline in PRL levels was observed during the periparturitional period. This pattern of PRL release was not correlated with changes in steroid hormone concentrations. The relative proportions of PRL size variants throughout delivery showed no apparent changes in all four subjects.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMedDate not supplied

Peripheral blood lymphocyte subsets and serum immunoglobulins in Sheehan's syndrome and in normal women during the menstrual cycle.

OBJECTIVE: There has been increasing evidence on the mechanisms underlying the interactions between the neuroendocrine and the immune systems, particularly in animal models with relatively few information in the human. In this study, we evaluate the cellular and humoral immunity in female patients with hypopituitarism and in normal women throughout the menstrual cycle in an attempt to determine the role of pituitary and gonadal hormones on the immune system. DESIGN: Serum immunoglobulins, peripheral blood lymphocyte subsets, and serum hormones were measured in eight patients with postpartum pituitary necrosis (Sheehan's syndrome) and in six normal women along different phases of the menstrual cycle, taking advantage of the lack of pituitary function and the cyclic variations in serum hormones, respectively. RESULTS: Patients with Sheehan's syndrome had higher T lymphocytes (CD2), including helper (CD4) and suppressor (CD8) cell subpopulations and B lymphocytes (CD19) when compared with normal menstruating women. An increase of serum IgA concentrations was also observed. Normal women showed little non-statistically different changes along the menstrual cycle in peripheral blood cell parameters and in serum immunoglobulin levels. CONCLUSIONS: a) Hypopituitarism in humans, in contrast with the animal model, may associate with immune up-regulation at both cellular and humoral levels; and b) hormonal changes along the normal menstrual cycle probably do not influence in great extent the immune system.

Adult↗
PubMedDate not supplied

[Current concepts on prolactin physiology: molecular variants and mechanisms of action].

Prolactin is a polymorphic hormone with multiple biological functions. The versatility in the actions of prolactin depends on its structural polymorphism and perhaps on the feasibility of prolactin to be converted into different bioactive forms. In this review we attempt to summarize information concerning the synthesis, structure and mechanisms of action, including the heterogeneous nature of prolactin and its possible physiological significance in humans.

Humans↗
PubMedDate not supplied

Fasting and postprandial serum insulin in Mexican adolescents with menstrual disorders.

PURPOSE: To investigate insulin serum concentrations in basal and stimulated conditions in a group of Mexican adolescents presenting menstrual disturbances. METHODS: A total of 77 post-menarchial adolescents were studied: 65 with a chronological age of 15 +/- 1.7 years (mean +/- SD) had persistent anovulation and represented the study group; 12 were normal ovulatory adolescents (15 +/- 1.2 years) and served as controls. Body mass index (BMI), waist to hip ratio (W/H), presence and severity of acne, hirsutism, acanthosis nigricans (AN) and follicular hyperkeratosis were recorded. Transabdominal pelvic ultrasound was performed and LH, FSH, estradiol, prolactin, testosterone, androstenedione and sex hormone binding globulin (SHBG) concentrations were measured in plasma by specific immunoassays. Glucose and insulin levels were determined in venous blood following an overnight fasting and two hours after a standardized breakfast. RESULTS: Anovulatory patients were divided in three groups depending on the presence of AN and overweight (BMI > 25). The insulin concentration in the study patients were remarkably higher than the values reported in the medical literature. Statistically significant differences were also found in fasting and postprandial insulin concentrations among the three anovulatory groups. Insulin values correlated with the severity of AN, W/H ratio, BMI and SHBG serum levels. CONCLUSIONS: Our study indicates that moderate to severe hyperinsulinemia is present in a high proportion of our adolescent anovulatory population. Whether hyperinsulinemia represents a transitory peripubertal event or is a predictive marker of chronic anovulation and metabolic derangement in adult life needs further investigation.

Adolescent↗