ANTERIOR-PITUITARY AND PITUITARY-DEPENDENT TARGET ORGAN FUNCTION IN MEN INFECTED WITH THE HUMAN-IMMUNODEFICIENCY-VIRUS

To evaluate pituitary and pituitary-dependent target organ function in men infected with the human immunodeficiency virus (HIV), 26 ambulato ry HIV-positive men (13 with acquired immunodeficiency syndrome [AIDS] ) and nine healthy control men were administered rapid sequential inje ctions of thyrotropin (TSH)-releasing hormone (TRH), gonadotropin-rele asing hormone (GnRH), ovine corticotropin (ACTH)-releasing hormone (oC RH), and human growth hormone (GH)-releasing hormone (hGHRH). Blood sa mples were collected before and for 90 minutes after the injections fo r immunoassay of pituitary hormones, cortisol, testosterone, and free thyroxine (fT(4)). Data were analyzed for each group of men considerin g basal, peak, and incremental responses to the releasing hormones, as well as the time course of response of each hormone. Mean basal serum GH concentrations were the same in all groups (control, AIDS, and non -AIDS HIV-positive), but stimulated GH levels were substantially highe r at all time points in both groups of HIV-positive subjects. Results for prolactin (PRL) were similar, although stimulated PRL levels were increased significantly only in the AIDS group. The mean basal serum T SH concentration and stimulated TSH levels at 60 and 90 minutes were s ignificantly greater in the AIDS group than in the control group. Basa l mean fT(4) concentration in the AIDS group was significantly less th an in the control group. Mean basal and stimulated serum (total) testo sterone concentrations in all groups were the same. However, basal ser um luteinizing hormone (LH) concentrations in both groups of HIV-infec ted men were significantly greater than in controls; stimulated (peak) LH levels were not different from control levels. Basal and peak stim ulated plasma ACTH concentrations were significantly increased in both HIV-infected groups. Basal serum cortisol levels were also greater, o n average, in HIV-infected groups, although stimulated (peak) cortisol responses were not different. These results indicate that basal serum concentrations of TSH, LH, ACTH, and cortisol are modestly increased in men with AIDS, and that maximum levels of GH, PRL, TSH, and ACTH st imulated by the releasing hormones are also increased in this group. M easurements obtained in the non-AIDS HIV-infected men showed a pattern generally similar to that obtained in men with AIDS, but less marked. The basis for the increased pituitary activity is unknown; we specula te that it is due to modestly impaired target organ function and to in creased hypothalamic stimulation. Copyright (C) 1996 by W.B. Saunders Company.