The response of growth hormone and prolactin to oral diazepam in diabetics

Abstract

We studied 8 insulin dependent stable young diabetics with a mean age of 20 yr. Each patient received 10 mg of diazepam orally after with drawing the baseline blood sample. Subsequent samples were obtained at 30 min intervals for 150 min. The oral administration of diazepam resulted in a significant increase in serum GH concentration from a baseline value of 5.3 +/- 1.2 ng/ml (mean +/- SE) at 0 point to a peak response of 16.5 +/- 5.9 ng/ml at 60 min (p less than 0.001). The plasma glucose concentration remained in the range of 200-267 mg/dl and did not change significantly during the entire testing period indicating that diazepam stimulates GH release in diabetics despite endogenous hyperglycemia. Eight normal subjects were also studied in an identical fashion. Although the mean baseline serum GH concentration in these normal subjects was significantly lower than that observed in the diabetics, (1.3 +/- 0.4 vs 5.3 +/- 1.2 ng/ml, p less than 0.05), the peak response did not differ significantly between the two groups (10.7 +/- 2.6 vs 16.5 +/- 5.9 ng/ml; NS). The baseline concentration of serum prolactin was similar in the diabetic and nondiabetic groups and the administration of diazepam resulted in no significant changes in both groups. Diazepam may be a useful agent in testing for GH reserve in normal subjects as well as in stable insulin dependent young diabetics.

Failure to Confirm Consistent Stimulation of Growth Hormone by Diazepam

“…Ad ministration of 10 mg diazepam i.v. or orally failed to affect prolactin or TSH secretion, in agreement with several studies examining the effects of oral diazepam on thyroid function and prolactin release [4][5][6][13][14][15].…”

“…We have no explanation for our failure to confirm these reports other than to suggest inherent differences in subjects or in the GH radioim munoassays used. Although the majority of our subjects were male as in previous reports [1][2][3][4][5], some of our subjects were older than those previously studied; positive reponses to diazepam were not related to age or sex in our subjects, however. Since most previous re ports of diazepam-induced GH secretion did not specify the anti-GH antibody used, it is difficult to know if major differences in assay specificity exist.…”

“…or i.v. diaz epam [1][2][3][4][5]. Other reports show decreased GH secretion during sleep or no effect of diazepam on hypoglycemia-stimulated GH secretion [6,9].…”

“…8 ml of blood were withdrawn at times -15,0, + 10, + 20, + 30, + 40, and + 60; the serum was separated and frozen at -2 0 °C for subsequent assay of growth hormone, pro lactin, thyrotropin and cortisol. 7 of our 10 subjects were also tested with 10 mg oral diazepam, since some previous reports of GH responses to diazepam used oral drug administration [1,3,5]. Subjects were pre pared as for i.v.…”

“…Serum cortisol rose in only 1 subject, precluding a stress-related explanation for the increase in growth hormone. We conclude that diazepam inconsistently stimulates growth hormone secretion and should not be relied upon as a test of growth hormone reserve.Diazepam has been reported to either stimulate growth hormone (GH) release [1][2][3][4][5] or result in decreased nocturnal secretion of this polypeptide [6], Additionally, diazepam premedication has abolished dopaminergic stimulation of GH in one study [7], The reported responses of serum cortisol to diaze pam have also been conflicting [6-9], In the 1 Supported by funds from the Research Service of the Veterans Administration. present study, we have re-examined the ef fects of acute administration of diazepam on anterior pituitary hormone secretion in hu mans.…”