Cyclic nucleotides in goats' milk: changes with physiological state.
Concentrations of cAMP and cGMP were measured in mammary secretions of goats. [cAMP] and [cGMP] increased during late pregnancy. At the onset of copious milk secretion, [cGMP] decreased while [cAMP] increased further. After the cessation of milking in late lactation, [cGMP] increased and [cAMP] tended to decrease. During withdrawal of food for 48 hr, the rate of milk secretion fell, [cGMP] increased and [cAMP] decreased; the changes were reversed on re-feeding. During temporary inhibition of milk secretion by intramammary treatment with colchicine, [cGMP] increased while [cAMP] decreased. It is concluded that cyclic nucleotide concentrations in milk change with physiological state.
D000818:Animals; D003078:Colchicine / Q000494:pharmacology; D000242:Cyclic AMP / Q000378:metabolism* / Q000502:physiology; D006152:Cyclic GMP / Q000378:metabolism* / Q000502:physiology; D005215:Fasting; D005260:Female; D006041:Goats; D007743:Labor, Obstetric; D007774:Lactation / Q000187:drug effects; D008892:Milk / Q000187:drug effects / Q000378:metabolism* / Q000502:physiology; D011247:Pregnancy
D000242:Cyclic AMP; D006152:Cyclic GMP; D003078:Colchicine