Relationships Between 24-hour LH and Testosterone Concentrations and With Other Pituitary Hormones in Healthy Older Men

Abstract

Objective To investigate the relationship between LH and T, which characteristics associate with the strength of this relationship, and their interrelationships with GH, TSH, cortisol, and ACTH. Design Hormones were measured in serum samples collected every 10 min during 24 h from 20 healthy men, comprising 10 offspring of long-lived families and 10 control subjects, with a mean (SD) age of 65.6 (5.3) years. We performed cross-correlation analyses to assess the relative strength between two timeseries for all possible time shifts. Results Mean (95% CI) maximal correlation was 0.21 (0.10–0.31) at lag time 60 min between LH and total T concentrations. Results were comparable for calculated free, bioavailable, or secretion rates of T. Men with strong LH-T cross-correlations had, compared to men with no cross-correlation, lower fat mass (18.5 (14.9–19.7) vs. 22.3 (18.4–29.4) kg), waist circumference (93.6 (5.7) vs. 103.1 (12.0) cm), hsCRP (0.7 (0.4–1.3) vs. 1.8 (0.8–12.3) mg/L), IL-6 (0.8 (0.6–1.0) vs. 1.2 (0.9–3.0) pg/mL), and 24-h mean LH (4.3 (2.0) vs. 6.1 (1.5) U/L), and stronger LH-T feedforward synchrony (1.5 (0.3) vs. 1.9 (0.2)). Furthermore, T was positively cross-correlated with TSH (0.32 (0.21–0.43)), cortisol (0.26 (0.19–0.33)), and ACTH (0.26 (0.19–0.32)). Conclusions LH is followed by T with a delay of 60 min in healthy older men. Men with a strong LH-T relationship had more favorable body composition, inflammatory markers, LH levels, and LH-T feedforward synchrony. We observed positive correlations between T and TSH, cortisol, and ACTH.

Morphometric analysis of somatotropic and folliculostellate cells of human anterior pituitary during ageing

“…In their fundamental work, Schwartz et al [8] reported that the function of the anterior lobe of the pituitary gland probably relies on the integration of multiple received input signals, including hypothalamic, peripheral, and intrapituitary, which may have stimulatory or inhibitory effects on the hormone production. Interactions of somatotropic (GH) cells with other hormonal and non-hormonal pituitary cells in healthy elderly appear to be very important [9,10,11]. Pituitary folliculostellate cells (FS) can release various products into the intercellular space, and thus can influence the functioning of neighboring hormone-producing cells [12].…”