Serum prolactin is associated with apoptosis in men with human immunodeficiency virus infection

We examined the in vivo and in vitro production of prolactin (PRL) in 20 untreated HIV‐infected men compared to 14 uninfected men and its association with the cell cycle and apoptosis. Compared to uninfected men, the HIV‐infected men had: (i) higher fasting serum bioactive (BIO) PRL; (ii) lower serum immunoreactive (RIA) and BIO‐PRL responses to intravenous metoclopramide; (iii) greater BIO‐RIA PRL ratio both fasting and during intravenous metoclopramide; (iv) lower percentage of non‐stimulated PBMC in the G0/G1 phase, but a higher percentage in the S phase, of the cell cycle with normal response to Concanavalin‐A; and (v) higher in vitro production of BIO‐PRL by non‐stimulated PBMC, which was blocked after Concanavalin‐A. Fasting serum BIO‐PRL positively correlated with the percent of non‐stimulated PBMC in S + G2/M phases. The percentage of apoptotic PBMC negatively correlated with CD4+ T lymphocytes and with the area under the serum RIA–PRL curve, but positively correlated with the area under the curve for the BIO/RIA ratio. These results suggest that in these HIV‐infected men: (i) a diminished dopaminergic tone may exist, as an adaptive mechanism attempting to survive; and (ii) BIO‐PRL may participate as a cofactor in the stimulation of T‐cell proliferation.