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John J Orrego

Publications and source records attributed to John J Orrego.

6 recordsLinked to original sources
PubMed2004

Physiological testosterone replenishment in healthy elderly men does not normalize pituitary growth hormone output: evidence against the connection between senile hypogonadism and somatopause.

Normal aging in men is accompanied by lower serum testosterone (T), GH, and IGF-I concentrations. The mechanisms of the age-related diminution in the activity of the somatotropic axis (somatopause) are uncertain. Several explanations have been proposed, including a lower hypothalamic GHRH output. The aim of the present study was to test the hypothesis that the physiological hypogonadism that accompanies normal aging is responsible for GHRH deficiency. We assessed the suppressibility of spontaneous and GHRH-stimulated GH secretion by a specific competitive GHRH receptor antagonist in seven elderly (61-76 yr old) and six young (20-23 yr old) healthy nonobese men. Elderly men then received transdermal T (5 mg/d) for 5-6 wk and had the same experiment repeated. Mean final total T, free T, and dihydrotestosterone increased in elderly men [521.5 +/- 56.3 vs. 395.4 +/- 57.2 ng/dl (P = 0.021), 13.8 +/- 1.3 vs. 10.1 +/- 1.7 pg/ml (P = 0.017), and 71.4 +/- 8.9 vs. 41 +/- 8.1 ng/dl (P = 0.004), respectively] to the levels found in their younger controls, but estradiol did not change (19.1 +/- 2.5 vs. 18.5 +/- 2.9 pg/ml; P = 0.67). GH pulse frequency or amplitude and maximum GH were not altered, and the integrated GH concentrations actually decreased. The percent suppression of GH output in the elderly did not change during GHRH antagonist infusion (35.8 +/- 2.6% vs. 27.7 +/- 6.5%; P = 0.29). We conclude that the T deficiency of old age is unlikely to be the proximate cause of the somatopause.

Administration, Cutaneous↗
PubMed2004

The role of radiation therapy after surgical resection of nonfunctional pituitary macroadenomas.

OBJECTIVE: Radiotherapy after aggressive surgical resection of nonfunctional macroadenoma (NFA) of the pituitary remains controversial. Historically, immediate postoperative radiotherapy has been recommended to decrease risk of recurrence. With the availability of high-resolution imaging, most neurosurgeons now withhold radiation until recurrence. There is relatively little evidence to support this practice, however. This study reviews postoperative results in a large number of patients with NFA, the majority of whom did not undergo prophylactic radiation. METHODS: Of the 258 patients who underwent surgery from 1979 to 1999 for NFA, medical records were available for 176. Forty-four patients were treated with immediate postoperative radiotherapy after tumor resection, and the remaining 132 patients were followed up with serial imaging studies and treated with radiotherapy only when a recurrence was documented by follow-up imaging. RESULTS: Patients in the group that received immediate postoperative radiotherapy at time of initial diagnosis and surgery did not differ significantly with respect to age or sex from those in the group that was observed. Five- and 10-year recurrence rates were 2.3 and 2.3%, respectively, for patients who received immediate postoperative radiotherapy, as compared with 15.2 and 50.5%, respectively, for patients who were followed up and did not receive radiotherapy unless there was evidence of recurrence or progression. No patient had symptomatic recurrence in the group that was observed if consistent follow-up was performed. Of the 26 patients who received radiotherapy at time of tumor recurrence or progression, 18 had adequate follow-up, and in all cases, the tumors either remained stable or regressed. CONCLUSION: Withholding radiotherapy after a high-percentage resection of NFA leads to a higher recurrence rate, but it avoids exposing all patients to the risks of radiation. Deferring radiotherapy for patients with complete or near-complete resection seems to be a safe and prudent approach, as our data suggest that recurrences may be detected early with high-resolution imaging and treated effectively with radiation at time of recurrence. Therefore, immediate postoperative radiotherapy may be eliminated for patients with complete or near complete resection of NFA and who agree to undergo close follow-up for a long period.

Adenoma↗
PubMedDate not supplied

Development of a macroprolactinoma in association with hormone replacement therapy in a perimenopausal woman with presumed idiopathic hyperprolactinemia.

OBJECTIVE: To describe a 48-year-old woman with presumed idiopathic hyperprolactinemia, who was found to have a macroprolactinoma after receiving hormone replacement therapy for almost 3 years. METHODS: We present a detailed case report, including a chronologic summary of clinical and laboratory findings as well as the drug history of our patient. The related literature is also reviewed. RESULTS: Premenopausal women with idiopathic hyperprolactinemia or microprolactinomas (<1 cm) are treated with dopamine agonists if fertility is desired or galactorrhea is bothersome. Otherwise, estrogens and progestational agents may be prescribed to regularize menses and prevent osteoporosis. Several case reports of prolactinoma formation or enlargement after exposure to exogenous estrogens have been published. In our patient, a perimenopausal woman with presumably idiopathic long-standing hyperprolactinemia, a macroprolactinoma developed within 3 years after initiation of hormone replacement therapy for management of perimenopausal symptoms. The only clue for ordering a pituitary imaging study in this case was a substantial increase in the level of the serum prolactin. Treatment with cabergoline normalized the patient's serum prolactin level and considerably decreased the size of her pituitary adenoma. CONCLUSION: It is postulated that exogenous estrogens could have an important role in tumor development or growth in some patients with idiopathic hyperprolactinemia. Therefore, it is recommended that women with idiopathic hyperprolactinemia or microprolactinomas treated with estrogens be considered for concomitant therapy with dopamine agonists. In all cases, serum prolactin levels should be diligently monitored.

Estrogen Replacement Therapy↗