Increased blood sugar coincident with ovulation in pigeons

Abstract

The data of an earlier communication by one of us have made it nearly certain that in healthy pigeons the suprarenals usually undergo extensive and regular enlargement at the period of ovulation. This result, in view of many facts which indicate an influence of the suprarenals on the mobilization of sugar, naturally leads to an inquiry as to whether the blood sugar also undergoes a similar and simultaneous increase in amount. The data reported here indicate that such an increase of blood sugar does also regularly occur. Scott and Honeywell concluded that in nonreproducing common pigeons of unknown sex the blood sugar amounts on the average to about 185 mgm. per 100 c.c. of blood as determined by MacLean's method. This same method was used in the present study and a similar amount of sugar was found for birds not actively ovulating. Ring doves in other than ovulation periods have, however, distinctly less blood sugar. Both of these kinds of pigeons, together with a third group—“scraggly” common pigeons—have been used by us. The “scragglies” are a mutational or aberrant form having a quite imperfect epidermal system (including the feathers) and bearing suprarenals earlier observed to show wide variation in size. Because of these variations it seemed desirable to include observations on this group. Males and females, both adult and young, of all the three groups have been studied, but only figures obtained for adult reproducing females are here considered. All samples were obtained by needlepuncture of the heart. Unfortunately, this procedure proved capable of producing occasional ovulations into the body cavity and also the resorption in the ovary of the nearly ripe ova. Since duplicate samples had to be taken from at least two different stages of ovulation it was possible to kill the bird only after the final sample was obtained.