Possible Interaction: Leucine and Progesterone

“Fourteen days after insert withdrawal progesterone concentrations were higher (P < 0.05) in Group L than in Group K (7.7 ± 4.3 vs. 5.6 ± 2.7 ng/mL) and in nulli- compared to pluriparous (9.1 ± 5.6 vs. 5.7 ± 2.1 ng/mL) ewes.”

“We also identified a marker of nutritional status, l-leucine , which lowers the progesterone threshold, indicating that oocytes integrate additional signals into their cell-fate decisions by modulating progesterone responsiveness.”

“ Progesterone rapidly shortened action potential duration, which was attributable mainly to enhancement of the slow delayed rectifier K+ current (IKs) under basal conditions and inhibition of L-type Ca2+ currents (ICa, L ) under cAMP-stimulated conditions.”

“E and E+P treatment reduced THDA and PHDA neuron activity under L :D, but did not affect these rhythms under DD.”

“In TIDA neurons, E or E+P treatment reduced the amount of DA released under L :D and DD and advanced the rhythm of DA turnover.”

“A valine substitution had a modest effect on activity but substitutions of leucine and alanine reduced progesterone C21-hydroxylase activity 5- to 7-fold, respectively, and the large hydrophobic amino acid, phenylalanine, reduced activity about 30-fold.”

“Leucine is a ketogenic amino acid that is also incorporated into lipids; progesterone depresses L-leucine incorporation into fatty acids by a glucose-dependent mechanism.”

“If EP was administered simultaneously with C, G, and L , all hor-monally induced increases in DNA, RNA, and nitrogen were inhibited.”

“Our results indicate that progesterone (10(-6) M) Blocks abruptly, around the germinal vesicle breakdown, the saturable transport of L-leucine.”