Pituitary-induced lactation in mammary gland explants from the pregnant tammar (Macropus eugenii): a negative role for cyclic AMP.
1. alpha-Lactalbumin and casein have been isolated from tammar milk. 2. alpha-Lactalbumin was induced in mammary explants by culture with anterior pituitary. 3. Casein was induced maximally in the presence of a physiological concentration of prolactin alone. 4. Progesterone did not inhibit the prolactin-induced synthesis of casein, alpha-lactalbumin, galactosyltransferase or fatty acids. 5. Both dibutyryl cAMP and a combination of cholera toxin and IBMX did significantly inhibit the induction of casein and alpha-lactalbumin. 6. Progesterone withdrawal is not a component of the lactogenic trigger in this marsupial but cAMP may be a common intracellular signal for negative control of lactogenesis in both marsupials and eutherians.
D000818:Animals; D002364:Caseins / Q000096:biosynthesis*; D004261:DNA Replication; D005227:Fatty Acids / Q000096:biosynthesis; D005260:Female; D005700:Galactosyltransferases / Q000378:metabolism; D006854:Hydrocortisone / Q000494:pharmacology; D007328:Insulin / Q000494:pharmacology; D007768:Lactalbumin / Q000096:biosynthesis*; D007774:Lactation; D008321:Mammary Glands, Animal / Q000166:cytology / Q000187:drug effects / Q000502:physiology*; D008394:Marsupialia / Q000502:physiology*; D009924:Organ Culture Techniques; D010903:Pituitary Gland, Anterior / Q000502:physiology*; D011247:Pregnancy; D011388:Prolactin / Q000494:pharmacology
D002364:Caseins; D005227:Fatty Acids; D007328:Insulin; D011388:Prolactin; D007768:Lactalbumin; D005700:Galactosyltransferases; D006854:Hydrocortisone