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19. Stimulation of Growth Hormone Secretion by Levodopa-Propranolol in Children and Adolescents.

Author

Collu, Robert, Leboeuf, Gilles, Letarte, Jacques, and Ducharme, Jacques R.

Subjects
*SOMATOTROPIN, *BIOGENIC amines, *JUVENILE diseases, *PEDIATRICS
Abstract

Abstract. Levodopa, 0.5 gm/1.73 sq m, and propranolol, 0.75 mg/kg, were administered orally to 23 children with short stature and 10 children suffering from various disorders. Glucose and insulin tolerance tests and arginine infusions were also utilized in some of these subjects to determine growth hormone (GH) response. Seventeen subjects with short stature had a GH peak greater than 5 ng/ml to the combined levodopa-propranolol provocative test (DPPT). The mean GH peak concentration obtained in this group was 19.6 +/- 1.8 (SEM) ng/ml, and in 94.1% of these children the peak was obtained at either 30, 60, or 90 minutes following the administration of the two drugs. Six subjects with short stature who failed to respond to the DPPT had abnormal responses to at least two other stimulatory tests and were classified as GH-deficient. Two subjects among the ten suffering from various disorders failed to respond to the DPPT. The first was a case of chromophobe adenoma of the pituitary gland with primary amenorrhea and luteinizing hormone deficiency, and the second a case of Hand-Schuller-Christian disease. The DPPT appears to be a reliable, safe, and easy-to-perform test to determine GH reserve. Pediatrics, 56:262, 1975. GROWTH HORMONE, LEVODOPA, PROPRANOLOL, BIOGENIC AMINES. [ABSTRACT FROM AUTHOR]

Published
1975
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20. Failure to alter psychophysiological reactivity in type a men with physical exercise or stress management programs.

Author

Seraganian, Peter, Roskies, Ethel, Hanley, James A., Oseasohn, Robert, and Collu, Robert

Abstract

Psychophysiological reactivity has been associated with heightened risk of coronary heart disease. Since behavioral processes may contribute to disease etiology, the possibility arises that they might also contribute to disease prevention. The capability of behavioral interventions to modify exaggerated reactivity in Type A men. was therefore, brought under experimental scrutiny. Subjects were 107 male managers. who met the following criteria: (1) no history or current signs of heart disease. (2) presence of Type A behavior pattern, and (3) exaggerated psychophysiological reactivity to mental stress. After matching for age and physical fitness level. participants were randomly assigned to one of three 10-week intervention programs: aerohic training, weight training and cognitive-behavioral stress management. Heart rate and blood pressure were monitored while challenging mental tasks were performed in pre-training and post-training laboratory sessions before and after the intervention programs. Although participants in the two physical activity programs showed the expected physical adaptations, no changes in psychophysiological reactivity were seen in the three groups. This negative result may indicate either that reactivity was not altered owing to the conditions of the present experiment, or that these behavioral interventions are truly without effect. [ABSTRACT FROM PUBLISHER]

Published
1987
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26. Endocrine effects of chronic administration of psychoactive drugs to prepuberal male rats. I: Δ9-tetrahydrocannabinol

Author

Collu, Robert, Letarte, Jacques, Leboeuf, Gilles, and Ducharme, Jacques R.

Abstract

The endocrine effects of the chronic administration of Δ9-tetrahydrocannabinol (Δ9-THC) to prepuberal animals were studied by injecting intraperitoneally three times a week for a month either 1 mg/kg or 10 mg/kg of the psychoactive drug or the vehicle to groups of Sprague-Dawley male rats starting at 21 days of age. At the end of the experiment the animals were autopsied in the morning, 30 to 45 min. after the last injection. Animals injected with 10 mg/kg had smaller tails and prostates than controls. Plasma levels of growth hormone (GH) and luteinizing hormone (LH) were decreased in both groups of experimental rats, while pituitary levels remained unmodified. Plasma levels of follicle stimulating hormone (FSH) were not affected by the drug. Brain levels of noradrenaline (NA), dopamine (DA), serotonin (5-HT) and 5-hydroxyindoleacetic acid (5-HIAA) were assayed in the 10 mg/kg experimental group and found comparable to those of the control group. These data indicate that Δ9-THC, the psychoactive ingredient of marihuana, when administered chronically to developing animals can inhibit the secretion of GH and LH and suppress prostate growth.

Published
1975
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27. Studies with Purified Immature Porcine Leydig Cells in Primary Culture1

Author

Bernier, Michel, Gibb, William, Haour, France, Collu, Robert, Saez, José M., and Ducharme, Jacques R.

Abstract

The steroidogenic capacity of purified immature porcine Leydig cells in culture was studied over several days. The cells were obtained by fractionating crude testicular interstitial cell suspensions on a discontinuous Percoll gradient (d = 1.037, 1.042, 1.052, 1.098 g/ml), and characterized by specific binding of 125I-human chorionic gonadotropin (hCG), testosterone (T) and cyclic adenosine 3′:5′-monophosphate (cAMP) production in response to hCG, and the enzymatic determination of Δ5-3β-hydroxysteroid dehydrogenase (3β-HSD) activity. The Leydig cells were recovered in a density band between 1.052–1.068 g/ml and grown in a chemically defined medium (Mather et al., 1981). In the absence of hCG, T production was low throughout the 6 days of culture. However, in response to hCG (10 mIU/ml), the cultured Leydig cells showed a progressive increase in T synthesis, which reached a maximum at Days 3–4 . 8-Br-cAMP (1 mM) induced a comparable rise in T production to that obtained with hCG throughout the culture period. In contrast, 8-Br-cAMP induced a near maximal increase in dehydroepiandrosterone (DHEA) production from Day 1. This paper demonstrates that purified immature porcine Leydig cells in primary culture are a valuable model to study the ontogeny of Leydig cell function.

Published
1983
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28. Reevaluation of Levodopa-Propranolol as a Test of Growth Hormone Reserve in Children.

Author

Collu, Robert, Brun, Gerard, Milsant, Francoise, Leboeuf, Gilles, Letarte, Jacques, and Ducharme, Jacques-Raymond

Subjects
*SOMATOTROPIN, *CHILDREN, *DOPA
Abstract

The growth hormone (GH) reserve of 15 short children was evaluated with the levodopa-propranolol test (DPT) and the sequential arginine-insulin test (AIT). Four patients failed to respond to both tests and were classified as hyposomatotropic. In the other 11 children, the mean GH peak response to the DPT was significantly higher than that to the AIT, mainly because five subjects who had a normal response to the DPT failed to respond to the AIT. These children had a generally poor yearly growth increment prior to testing associated in three with an obvious emotional problem, and were found at follow-up to have resumed a normal growth pattern. These data confirm the effectiveness of the DPT as a test of GH reserve. Although hypoglycemia can occur occasionally during test, this procedure is safer and easier to perform than the widely used AIT. Finally, the DPT seems to detect a category of children who have a temporary growth failure and nonresponse to the usual GH tests but who are not hyposomatotropic and consequently do not require human GH. [ABSTRACT FROM AUTHOR]

Published
1978
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