CYCLIC CHANGES IN BLOOD CALCIUM, PHOSPHORUS AND FAT IN RELATION TO EGG LAYING AND ESTROGEN PRODUCTION

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Abstract
The state and development of present knowledge concerning changes in blood Ca, P and fat, as these occur in relation to growth of ova and to estrogen production in egg laying vertebrates, is reviewed. Five items of original data are presented in 5 graphs. Two mature [female] doves maintained under constant daily dosage of gonadogen for 37 and 155 days, and 4 immature [male] and [female] pigeons injected daily with 1 mg. estrone for 29 days, showed significant but unexplained periodic fluctuations in serum Ca and fat. At each period of egg production in the pigeon the serum fat (less phosphatides) increased from about 470 mg. % to a maximum of about 2900 mg. % at 60 hrs. preceding the ovulation of the 1st egg. Although the oviduct in immature ring doves responded to estrogens in an essentially specific manner it also gave a measurable response to androgens when more than 1.0 mg. daily was administered. In adult ring doves the inj. of 3.0 mg. estradiol benzoate, in 3 doses over a 5-day period, gave only 1/2 as much oviducal hypertrophy as occurs at a normal egg producing cycle. This result indicates that these birds produce relatively huge quantities of estrogen at each cycle, and large amts. of estrogen are probably utilized by other egg laying vertebrates in the cyclic increase of their blood Ca, P and fat.