Abstract: Indole derivatives of formula (I) ##STR1## wherein R.sup.1, R.sup.2, R.sup.3 and R.sup.4 may be hydrogen or lower alkyl optionally substituted by halogen; A.sup.1 represents a straight or branched alkylene chain containing from 2 to 4 carbon atoms; R.sup.5 is hydrogen or a straight or branched alkyl group; A.sup.2 is a straight or branched, saturated or unsaturated hydrocarbon chain containing from 2 to 6 carbon atoms; and R.sup.6 is selected from a group consisting of various structures, have been found to exhibit central nervous system activities.

Abstract: Non-surgically correctable infertility or sub-fertility in adult men having poor semen quality is treated with injections of human Growth Hormone (hGH) in daily doses of 1-10 IU/m.sup.2 or in doses in combination with gonadotrophins. Increase in total semen volume and total sperm number per ejaculate up to normal figures is obtained.