Depression of hypercapnic ventilatory drive by testosterone in the sleeping infant primate

Abstract

In postnatal infants, there is similarity between the time course of transient gonadal steroid secretion and the age-related incidence of sudden infant death syndrome (SIDS). The cause of death in SIDS is generally thought to be a ventilatory arrest, but the mechanism responsible for such an event remains unknown. Testosterone has been demonstrated to depress ventilatory drive and increase sleep apnea in adult men. We tested the hypothesis that the gonadal steroid testosterone depresses infant ventilatory drive during sleep. Three newborn male infant primates were gonadectomized after birth. Ventilation was observed and quantified for each animal during completely natural unencumbered sleep by plethysmography for an average of 16 wk. Ventilatory patterns were recorded, and ventilatory drive was challenged with hypercapnia and hypoxia during quiet sleep on the night before and the night after testosterone administration. Hypercapnic ventilatory drive during sleep was significantly depressed by an average of 33.6% on the night after compared with the night before testosterone administration. Depression of the response to hypercapnia after testosterone was not accompanied by any change in resting minute ventilation measured during quiet sleep. Hypoxic ventilatory drive, incidence of apneic events, and length of apnea were not different after testosterone. The effects of injecting a placebo on ventilatory patterns and drive were tested by giving the placebo to all animals on several test weeks. Placebo injections produced no significant change in any measured parameters. These results support the hypothesis that testosterone depresses hypercapnic ventilatory drive during sleep in the infant primate.(ABSTRACT TRUNCATED AT 250 WORDS)