Role of maternal and foetal adrenal activity in the development of the rat mammary gland near term.
The essential role of adrenal corticosteroids in the initiation of mammary gland secretory activity near term in the rat has been investigated. Mammary gland DNA and RNA were estimated as a quantitative indication of the extent of mammary gland development. Maternal adrenalectomy or hypophysectomy resulted in a decrease in the mammary gland RNA:DNA ratio. Treatment of adrenalectomized animals with cortisol acetate completely restored the RNA:DNA ratio to the control level. Treatment of hypophysectomized animals with cortisol acetate resulted in an increase in the RNA:DNA ratio but did not restore the ratio to the control level. Removal of the pups had no effect on the RNA:DNA ratio. The findings are discussed in relation to the foetal and maternal contribution to the level of glucocorticoids in the circulation and with respect to changes in mammary gland sensitivity to lactogenic stimulation near term.
D000305:Adrenal Cortex Hormones / Q000502:physiology*; D000311:Adrenal Glands / Q000196:embryology / Q000502:physiology*; D000315:Adrenalectomy; D000818:Animals; D005260:Female; D006854:Hydrocortisone / Q000494:pharmacology; D007016:Hypophysectomy; D007774:Lactation; D008321:Mammary Glands, Animal / Q000187:drug effects / Q000254:growth & development*; D011247:Pregnancy; D012313:RNA / Q000032:analysis; D051381:Rats
D000305:Adrenal Cortex Hormones; D012313:RNA; D006854:Hydrocortisone