Mary Ann Tabrizi

Plasma Levels of Imipramine (IMI) and Desmethylimipramine (DMI) and Clinical Response in Prepubertal Major Depressive Disorder: A Preliminary Report

Abstract A study is in progress to examine the relationship between clinical response to imipramine (IMI) of prepubertal major depressive disorder at 5 weeks and plasma levels of IMI and its metabolite desmethylimipramine (DMI). Data are presented on the first 13 children in the study. A strong correlation is emerging in nondelusional subjects between total plasma level and clinical response. A total plasma level of 146 ng/ml separates respondent from nonresponders. These data parallel those previously reported in adult major depressive disorder by several investigators.

Dopaminergic factors in human prolactin regulation: A pituitary model for the study of a neuroendocrine system in man

This study in normal male subjects further investigates the effects of dopaminergic-antidopaminergic interactions as manifested by the prolactin response to dopamine and neuroleptic drugs. Incremental doses of dopamine hydrochloride (4 μg/min, 15 μg/min, 60 μg/min, 300 μg/min) were infused fused at a constant rate over 90–120 min after a fixed dose of a neuroleptic drug (sufficient for about half of the maximal prolactin response) had been given IV. A dose of dopamine in the order of 15–60 μg/min appeared to match the “los” of endogenous dopaminergic inhibition due to the antidopaminergic effect of the neuroleptic drug. The lactotrophic cells of the pituitary gland are suggested to serve as a model in man for the study of some basic neurohormonal mechanisms.

Prolactin responses to haloperidol in normal young women

The prolactin (PRL) responses to intramuscular haloperidol (HPD) (0.5, 1.0, and 1.5 mg) were evaluated in six normal premenopausal women during the follicular and luteal phases of their menstrual cycles. These were compared to the PRL responses to these doses of HPD in normal young men. PRL responses to HPD did not differ between the follicular and luteal phases. The mean log-transformed PRL response to the lowest HPD dose (0.5 mg) in women was less than that in the men, but the women had greater PRL responses than the men to the higher haloperidol doses (1.0 mg and 1.5 mg).

Effect of metergoline on the diurnal prolactin responses to insulin-induced hypoglycemia in normal men☆

Abstract (1) Insulin tolerance tests were performed at 0900 and 1800 hr on six young healthy men, under basal conditions and after metergoline pretreatment. (2) The hypoglycemia induced by insulin during the two tests was not significantly different. (3) Both morning and evening basal prolactin (PRL) levels were significantly lowered by metergoline. (4) Insulin hypoglycemia-induced PRL release was significantly inhibited by metergoline, both in the morning and in the evening. (5) Although dopaminergic mechanisms may account for these effects of metergoline, serotonergic mechanisms cannot be ruled out.

Diurnal hormonal responses to thyrotropin-releasing hormone in normal men

Bolus injections of synthetic thyrotropin-releasing hormone (TRH) were administered to five young normal men in the morning (0900 hr) and the evening (1800 hr) on different days. Frequent blood samples for prolactin (PRL) and TSH analyses were collected before and after TRH infusion. Although there were no differences between the morning and the evening basal PRL levels, a significantly greater PRL response to TRH in the evening was observed (delta PRL, a.m. vs p.m., p less than 0.025). Since TRH stimulates PRL through a direct effect on the pituitary, our data suggest that there is a diurnal variation in the pituitary lactotroph responsiveness to TRH. On the other hand, a.m. and p.m. basal and TRH-stimulated TSH responses were virtually identical.