Biomedical subjects

J J Orrego

Publications and source records attributed to J J Orrego.

5 recordsLinked to original sources

PubMed2001

Semiquantification of hypothalamic GH-releasing hormone output in women: evidence for sexual dimorphism in the mechanism of the somatopause.

The neuroendocrine mechanisms underlying the decline of GH with aging (somatopause) are uncertain. We recently found that the age-dependent diminution of the hypothalamic GH-releasing hormone (GHRH) output contributes to the somatopause in men. As the regulatory mechanisms of GH secretion are sexually dimorphic, we assessed the suppressibility of spontaneous and GHRH-stimulated GH secretion by graded doses of a specific competitive GHRH receptor antagonist in nine young (20-27 yr old) and eight elderly (65-77 yr old) healthy nonobese women to semiquantify hypothalamic GHRH output. Nocturnal mean GH was lower in elderly women (2.2 +/- 0.4 vs. 0.9 +/- 0.2 microg/liter; P = 0.01). Graded boluses of GHRH-44 resulted in similar GH responses in both populations (P = 0.28). Graded infusions of GHRH antagonist inhibited in a dose-dependent manner the GH responses to GHRH in both groups (P = 0.0001-0.04). The dose-inhibition curve for the lowest GHRH bolus dose was shifted to the left compared with the highest one (P = 0.04). However, the dose-inhibition curves for spontaneous GH secretion were not different in young and elderly women (P = 0.50). Thus, the female somatopause is not associated with a measurable decrease in hypothalamic GHRH output. When the dose-inhibition curves for young men and young women were compared, the latter was shifted to the left (P = 0.009), suggesting that the somatotropic system in women operates with less GHRH. We conclude that the contribution of endogenous GHRH to the maintenance of GH secretion and the neuroendocrine mechanisms of somatopause in humans are sexually dimorphic.

Adult↗

PubMed2000

Rapid re-expansion of a macroprolactinoma after early discontinuation of bromocriptine.

Prolactin (PRL)-secreting pituitary adenomas are the most common functioning pituitary tumors. Medical treatment with dopamine agonists is the therapy of choice for macroprolactinomas (> or = 10 mm). Withdrawal of bromocriptine after weeks or months of uninterrupted therapy has been associated with rapid tumor re-expansion as evidenced by x-ray and CT scanning of the pituitary region. We report a patient with a giant macroprolactinoma who had a dramatic response to bromocriptine (tumor volume shrinkage of 53% within a month) but rapid re-expansion to its original dimensions one week after discontinuation of bromocriptine. To our knowledge, this is the first time that the rapid shrinkage/re-expansion of a macroprolactinoma has been documented with serial MRI scans.

Adult↗

PubMed2000

Pergolide as primary therapy for macroprolactinomas.

The objective of this study is to determine whether pergolide therapy is an effective modality for the de novo treatment of patients with macroprolactinomas. Twenty-two consecutive patients with macroprolactinomas were included in the study and followed prospectively. These included 16 men and 6 women in whom pregnancy was not of concern. Pergolide was administered once or twice a day depending on the patient's preference. Ten patients received 0.1 mg daily as a maintenance regimen and in the others the daily dose ranged from 0.05 to 0.5 mg. Eight patients reported minor but tolerable side effects. One patient had to be switched to cabergoline because of intolerable nausea. After a mean of 12 months (range, 3-36), mean PRL levels declined from 3,135 ng/ml (range, 126-31,513) to 50 ng/ml (3-573), representing a mean PRL suppression of 88% (range, 0-99). PRL levels became normal in 15 patients and decreased to 25-40 ng/ml in 3 others. The mean tumor volume shrinkage was 25% or greater in 19 patients (86%), 50% or greater in 17 patients (77%), and 75% or greater in 10 patients (45%). Visual abnormalities were reversible after pergolide therapy in all but 1 of 12 patients with initially abnormal formal visual testing. Two out of 4 premenopausal women did not normalize PRL levels and had persistent oligomenorrhea. Testosterone was low in 14 men at presentation and normalized in 3 with pergolide therapy. We conclude that pergolide is a safe, inexpensive, and generally well-tolerated dopamine agonist for the treatment of macroprolactinomas in men and women in whom pregnancy is not of concern. In these specific populations, pergolide may become the first-line therapy for treatment of macroprolactinomas.

Adolescent↗

PubMed2000

Pituitary disorders. Drug treatment options.

Pituitary diseases are relatively common entities in the general population. They include pituitary adenomas and hypopituitarism. Pituitary tumours can cause symptoms of mass effect and hormonal hypersecretion that can be reversed with surgical resection or debulking of the adenoma, radiotherapy, or medical treatment. Transsphenoidal adenomectomy is the treatment of choice for acromegaly, Cushing's disease, gonadotropin-secreting tumours; and thyrotropin (TSH)-secreting adenomas. Pituitary irradiation and medical therapy are secondary options. Conversely, medical treatment is the primary choice for prolactinomas. Dopamine agonists are very effective in the treatment of prolactin (PRL)-secreting tumours, with rates of control as high as 80 to 90% for microprolactinomas (< 10 mm) and 60 to 75% for macroprolactinomas (> or = 10 mm). Somatostatin analogues have also shown efficacy in patients with acromegaly who have not responded to surgery or in patients with TSH-secreting adenomas who have not improved with surgery and radiotherapy. In patients with Cushing's disease, who are not cured surgically or who relapse after pituitary adenomectomy and irradiation, steroidogenic inhibitors can be an efficient method of controlling the hypercortisolism. Pituitary insufficiency is the partial or complete loss of the anterior hypophyseal function, which is due to hypothalamic or pituitary disease. Although the classic sequence of loss of pituitary secretion is growth hormone (GH), gonadotropins, TSH, and corticotropin (ACTH), the order to begin the replacement therapy of the deficient hormone(s) is cortisol, thyroxine, androgens/estrogens and, if necessary, GH. There are multiple preparations that can be used to achieve clinical and biochemical improvement. In general, the hormone replacement therapy is lifelong.

Adenoma↗

PubMedDate not supplied

Bilateral symmetrical basal ganglia infarction after intravenous use of cocaine and heroin.

A case is reported of a young man who developed bilateral symmetrical basal ganglia infarcts after intravenous use of cocaine and heroin. Ischemic infarcts of the brain are a known complication of to cocaine use, alone or in combination with heroin (speed balling). This symmetrical occurrence of infarction, however, is unusual and has not been reported after cocaine use.

Adult↗