Search

Twenty-four healthy subjects were submitted to a computer-based performance evaluation system. The set of tests required sustained attention, and the last test was expressly designed to cause a moderate, acute psychological stress. Compared to baseline levels, both serum ACTH and beta-endorphins were increased after psychological testing in all subjects. Serum prolactin showed a slight and statistically nonsignificant decrease compared to baseline values. These results question the belief that psychological stress stimulates prolactin secretion, whereas it suggests that serum ACTH and beta-endorphins are reliable indicators of acute psychological stress.

We have examined the effects of 1 alpha-hydroxycolecalciferol (1 alpha) (1.5 micrograms for 5 days) on serum osteocalcin (OC) and other parameters of bone and mineral metabolism in 20 osteoporotic women and 11 age-matched normal women. After 1 alpha administration, a statistically significant (p less than 0.01) increase of serum OC, calcium and phosphate and urinary calcium and hydroxyproline was observed. In contrast, alkaline phosphatase was unchanged. There was no significant difference between normal and osteoporotic women in the changes of any of the parameters we monitored. In particular, OC increased in a comparable way in both groups. Thus, by means of an index that reflects the global activity of the skeleton, we could not find any apparent defect of osteoblastic responsiveness to the drug in osteoporotic subjects.

Gonadotropin behaviour (basal plasma values and pituitary responses to GnRH) in hyperthyroid patients was studied. LH values (both basal and pituitary responses) higher than the controls were documented. Thyroid hormones seem to modulate pituitary response to GnRH for LH only in hyperthyroid patients of both sexes. In order to explain the mechanism of the action of thyroid hormones, rather than the possibility of peripheral effect on binding capacity of the proteins for circulating steroids, a central interaction at medial eminence level is suggested.

The correlation between dopamine-serotonin systems and sexual behaviour and the influence of these two amines on GH secretion is well known. We evaluated GH responses (maximum increase (delta) after OGTT and mean increase (delta M) after insulin test) in a group of 32 males suffering from erective impotence with impotence with abnormal reaction to a glucose tolerance test. Results were compared with those obtained in a group of 13 normal controls. No significant difference in basal values and dynamic responses between the two groups was present. Our data suggest that GH doesn't decrease the tolerance to glucose in these patients. The abnormal values observed during a glucose tolerance test may be due to some agent involved in the interactions between limbic system, ventral lateral and ventral medial hypothalamic nuclei and dopamine-serotonin systems. No influence by this system on GH secretion is evident.

Swiss male mice were individually-housed or maintained in groups of 8 from weaning until 80 days of age. At this time, the grouped mice were allocated to new groups of 5-6 previously unfamiliar individuals. Identified dominants were then caged with two clearly submissive males for 1 week. At this time hypothalamic samples were taken from the dominant and one subordinate and from a number of long-term individually-housed males. A radio- immunoassay for LHRF was carried out. The levels of this hypothalamic releasing factor were significantly higher in both dominant and subordinate grouped mice than in 'isolates'. Mice of differing social status showed comparable titres of this hormone. The results suggest that social conflict and/or disturbance augments this factor in mice irrespective of the social status achieved by individual animals., (Copyright © 1985. Published by Elsevier B.V.)