Abstract
Summary. Experiments designed to find the pathogenesis of the infertility caused by fasting mice for 18 to 48 hr at about the time of mating showed that: (a) within 4 hr of removal of all food the blood-glucose level fell to about half, and that this fall was delayed for about 24 hr by adding glucose to the drinking water; (b) protamine zinc insulin reduced both blood-glucose level and littering rate; (c) 2-deoxy-d-glucose (2dg) inhibited ovulation and caused the death of tubal ova; (d) fasting, insulin and 2dg appeared to cause similar effects upon the fertility; and (e) the expected infertility of fasted mice was prevented by the administration of human chorionic gonadotrophin and progesterone at the appropriate times. The evidence suggested that the primary biochemical disturbance was hypoglycaemia and that this inhibited adenohypophysial gonadotrophic function.