Dependence of Ovarian Spiral Arteries on the Trophic Action of Estrogens. ∗

Patterns of spiral arteries in rabbit 1 , 2 , 3 and human Sovaries 4 , 5 have been described. Although there are differences in the arrangement of these vessels in the two species, homologous parts may be discerned. In the human, the ovarian artery passes along the hilus of the ovary, inosculating with its uterine branch. This may be called the basic branch and compares with the same vessel in the rabbit which lies wholly outside the ovary. There are numerous short tortuous vessels arising primarily from this basic vessel in the human and these primary branches compare with the single (or sometimes double 2 ) ramus ovaricus in the rabbit. In the human, each primary branch normally gives rise to a number of still smaller helical blood vessels that pass in the folds of the posterior duplicature of the broad ligament as this envelopes the ovary. These secondary vessels compare with the ovarian spiral arteries originally described in the rabbit. 1 , 2 They give rise in turn to clusters of still smaller tertiary spiral arteries.

In the course of injecting the blood vessels in a series of about 60 pairs of human ovaries, 5 observations have been made on the distribution and character of the secondary and tertiary blood vessels in the human ovary. It is clear that, in the absence of estrogen these vessels undergo progressive involution and eventually disappear. They are highly developed, dense and numerous only in the presence of estrogen. The evidence for this is as follows:

a) In 4 hypertensive subjects past the menopause, the ovaries were sclerotic, one endometrium atrophic, and there were few or even no secondary and tertiary ovarian spiral arteries.

b) One normotensive subject with a recent menopause had a uterus with an actively proliferating endometrium. Her ovaries were sclerotic, but the secondary and tertiary ovarian arteries were profuse and well developed although the vessels were more widely spaced than in menstruating women.

c) Two hypertensive subjects, not yet past the menopause, possessed non-sclerotic ovaries. The ovarian spiral arteries were luxuriant and profuse.

d) Three normotensive premenopausal women possessed sclerotic ovaries and either proliferative, or early secretory endometria. The secondary and tertiary ovarian spiral arteries were profuse and highly developed.