Changes in fat cell morphology during lactation in the mouse.

Abstract

AbstractA comparison was made of changes in the morphology of fat cells in the intact mammary gland, de‐epithelialized mammary fat pad, and the parametrial fat pad of female C3H mice during lactation. Mammary fat pad not in contact with actively secretory epithelium shows partial loss of fat during lactation (systemic effect) while in the presence of such epithelium there is much greater loss of fat (systemic plus local effect). In the same animal the parametrial fat pad shows greater depletion during lactation than the de‐epithelialized mammary fat pad. The extent of fat depletion is dependent on the number of nursing young and the duration of lactation. In the intact mammary gland and parametrial fat pad, marked change in fat cell structure is not seen in pregnancy except possibly at the very end; after weaning, replenishment of lactation‐depleted fat cells is conspicuous by 48 hours. The basic ultrastructure of mammary fat cells and the kinds of changes they undergo during depletion do not differ from those described for other mammalian adipose tissues.