PubMed Health⌕ Search

Biomedical subjects

R W Rebar

Publications and source records attributed to R W Rebar.

88 records · Page 5Linked to original sources
PubMed1980

Acute steroidogenic responsiveness to human luteinizing hormone in hypogonadotropic hypogonadism.

The responses of circulating levels of androgens, estrogens, and their C-21 biosynthetic precursors to a 6-h constant infusion of human Lh (hLH; 2000 IU) were studied in four males with hypogonadotropic hypogonadism (HH) and compared with those in normal male controls. Although similar levels of circulating LH were achieved, the initial and secondary increases in testosterone were significantly greater in the hypogonadotropic subjects than in the normal controls. In contrast, the responses of estradiol, estrone, 17 alpha-hydroxyprogesterone, and 17 alpha-hydroxypregnenolone to exogenous hLH were significantly lower in HH than in normal controls. The data demonstrate a different pattern of testicular steroidogenic responsiveness after pharmacological doses of hLH, with increased concentrations of circulating testosterone in subjects with HH compared to a disproportionate increase in estrogen and progestin levels in normal men.

17-alpha-Hydroxypregnenolone↗
PubMed1979

Replacement oral ethinyloestradiol therapy for gonadal dysgenesis: growth and adrenal androgen studies.

We have studied growth and adrenal dehydroepiandrosterone (DHA) responses to iv synthetic adrenocorticotrophic hormone (ACTH, Cortrosyn) in 6 girls with gonadal dysgenesis before and during treatment with low-dose ethinyloestradiol (EOe2). In all patients there was a statisfactory induction of secondary sexual characteristics including increase in breasts and public hair and onset of withdrawal bleeding within 6 months of therapy. Height velocity increased from 2.8 +/- 0.9 cm/year pre-treatment to 5.3 +/- 1.5 cm/year (P less than 0.02) in the first year. There was deceleration to 1.9 +/- 1.1 cm/year in the second year. There was no disproportionate advancement in bone age and thus, presumably, no loss of ultimate height. We could demonstrate no change in basal or ACTH-stimulated levels of DHA, a specific adrenal androgen, to account for the increased public hair and growth in these patients.

Administration, Oral↗
PubMed1977

Pubertal progression in the presence of elevated serum gonadotropins in girls with multiple endocrine deficiencies.

Pubertal progression in the presence of abnormally elevated serum gonadotropins was followed over several years in two girls with multiple endocrine deficiencies and mucocutaneous candidiasis. Both had hypoparathyroidism and one had adrenal failure as well. A serum level of progesterone (8 ng/ml) consistent with ovulation was documented in the one girl who had regular monthly menses. High serum levels of FSH (30--60 mIU/ml) at times when serum estradiol was in the normal pubertal range (100--200 pg/ml) may indicate partial ovarian end-organ resistance or failure. Since premature menopause is associated with this syndrome, we postulate that we are observing puberty in girls whose ovaries are in the early stages of a destructive process which may eventually result in irreversible ovarian failure. A possible explanation could be the existence of increased resistance to gonadotropins at the ovarian level because of gonadotropin receptor antibodies or an inherent receptor defect.

Adolescent↗
PubMed1976

Pituitary function in pseudocyesis.

Neuroendocrine assessments were made in a 16-year-old girl with pseudocyesis of 38 weeks duration. Basal levels of pituitary LH and PRL, but not of FSH, were markedly elevated and the pulsatile pattern of LH and PRL appears to be exaggerated compared with those found in normal cycling women. Growth hormone levels were normal, with an appropriate increase after arginine infusion and l-dopa. The increased luteotropic action resulting from increased plasma LH and the lactogenic action of increased plasma PRL were associated with the presence of luteal function and galactorrhea. The dominant role of psychic mechanism(s) in causing hypersecretions of LH and PRL is suggested by the almost immediate fall in the serum concentrations and the rapid resolution of abdominal distention after the diagnosis was revealed to the patient.

Adolescent↗
PubMedDate not supplied

Unanswered questions in hormonal replacement therapy.

This review addresses many of the unanswered questions existing relative to the use of exogenous estrogens and progestins in postmenopausal women (PMW). The literature in the field is reviewed and summarized, with a particular effort to identify key questions of major concern. The effect of selection bias on conclusions reached from retrospective studies involving hormone replacement therapy (HRT) has not been examined. Less is actually known about the effects of progestins than estrogens. Many of the endocrine changes that occur with aging remain poorly defined. Effects of estrogens and progestins on the breast and on breast cancer are unclear. Estrogens have recognized beneficial effects and progestins have detrimental effects on lipoprotein metabolism. Estrogens also have direct effects on the vasculature and may impact on cardiovascular risk in other ways. Although estrogens are the only agents known to eliminate hot flushes, the mechanism by which flushes arise is not known. Estrogens may have ameliorating effects on mood and behavior and may improve dementia, but research in this area has been limited to date. Lastly, the preferred estrogens and progestins, their dosages and routes of administration, remain to be more completely defined.

Breast↗
PubMedDate not supplied

Dietary inclusion of whole soy foods results in significant reductions in clinical risk factors for osteoporosis and cardiovascular disease in normal postmenopausal women.

OBJECTIVE: To determine the effects of dietary inclusion of soy foods on clinical markers for cardiovascular disease (CVD) and osteoporosis in normal postmenopausal women. DESIGN: This was a single open-group prospective clinical intervention. Forty-two normal postmenopausal women consumed three daily servings for 12 consecutive weeks of whole soy foods containing approximately 60 mg/d of isoflavones. Blood and urine specimens were obtained at baseline and after 12 weeks of dietary intervention. RESULTS: Serum and urine levels of individual and total isoflavones increased significantly (7-19 fold, p < 0.001) from baseline. A significant increase (9.3%, p < 0.05) in the mean lag-time of low-density lipoprotein cholesterol oxidation was seen and was positively correlated with serum phytoestrogens (p < 0.05). Significant increases were found in mean levels of high-density lipoprotein cholesterol (HDLc) (3.7%, p < 0.05) and serum osteocalcin (10.2%, p < 0.025). Significant decreases were observed in total cholesterol:HDLc ratios (5.5%, p < 0.006) and mean urinary N-telopeptide excretion (13.9%, p < 0.02). Urinary excretion of total isoflavones was negatively correlated with very-low-density lipoprotein cholesterol, triglycerides, and total cholesterol:HDLc ratios (p < 0.04). No significant changes from baseline in HDLc peroxidation, total cholesterol, triglycerides, low-density lipoprotein cholesterol, very-low-density lipoprotein cholesterol, bone-specific alkaline phosphatase, follicle-stimulating hormone, or estradiol levels were observed. CONCLUSIONS: Dietary inclusion of whole soy foods containing 60 mg/d of isoflavones results in significant serum levels of phytoestrogens and reductions in several key clinical risk factors for CVD and osteoporosis in normal postmenopausal women. Long-term, placebo-controlled clinical trials are needed to evaluate the effect of phytoestrogens on the clinical endpoints of CVD and osteoporosis in this population.

Cardiovascular Diseases↗
PubMedDate not supplied

Evaluation and management of menstrual dysfunction in athletes.

The prevalence of menstrual dysfunction is greater among athletes than in the general population. Many factors undergo change during the course of an athletic training program and any or all of these may contribute to disturbances in menstrual cyclicity. All athletes with oligomenorrhea, amenorrhea, or menarcheal delay require thorough evaluation to rule out serious pathological conditions, since the diagnosis of exercise-associated menstrual dysfunction can be made only by excluding other etiologic factors. Most athletes who have these problems should be treated to prevent undesirable sequelae.

Amenorrhea↗