The Stroma

FEW observations have been reported concerning the action of gonadal hormones on the mammary stroma. Perhaps the local deposition of fat and the increased connective tissue framework of the breast characteristic of sexual activity in women is directly caused by the extending glandular structures, and is not an independent reaction to gonadal hormones. However, if the glandular tissue grows in response to stimulation by gonadal hormones in normal circumstances, the stroma also grows. Folley, Scott Watson & Bottomley (1941 a) noticed some enlargement of the udder in immature castrated male goats which had been submitted to a prolonged administration of diethylstilboestrol or its dipropionate, but there is no evidence to show whether this enlargement was merely secondary to the increased growth of mammary ducts or not.

Ingleby (1942) has noticed changes in the mammary stroma during the oestral cycle in women, the periductal connective tissue becoming more transparent and apparently oedematous during the second half of the cycle. Possibly this is an effect of progesterone alone or in co-operation with oestrogen.

The Nipple

Steinach & Holzknecht (1916) implanted ovaries taken from littermates into castrated male guinea-pigs and rats. One consequence was a pronounced enlargement of the nipples. Lipschiitz & Tiitso (1925) confirmed this effect in guineapigs and repeated the experiment on rats with the same result. In rats hypertrophy of the nipples was noticed 9 days after the grafting and they grew to as much as 6 mm. in length. Kunde, D'Amour, Gustavson & Carlson (1930) gave injections of oestrin in daily doses ranging from 25 to 800 r.u. to immature dogs of which one was a male and three were females. The injections caused enlargement of the nipples in each of the animals. The reaction was definite and pronounced. Moricard (1934) gave 1 mg. of oestrin divided into two doses to three immature guinea-pigs weighing 130, 140 and 145 g., and killed them at the 100th hour. Their nipples at this time were 4 times the length normal for their age. Nelson (1936 c), in a review of the hormone control of the mamma, says that in males and spayed females of all species tested oestrogen induces growth of the nipples.