[Effects of amino acids on the membrane potential of toad oocytes and the underlying mechanism].
Of the 23 amino acids tested for their effect on the membrane potential of incubated toad oocyte, alanine, leucine and lysine were found to cause a decrease of polarization (depolarization) and K+ permeability, while tryptophan causes an increase of potential (hyperpolarization) and K+ permeability. For the rest 19 amino acids, no membrane effects were observed. Accompanying the alanine, leucine and lysine caused depolarization, the oocyte progesterone content became doubled and the maturation process hastened. These effects could be completely blocked by 1 mmol/L dibutyryl cAMP (db-cAMP) or 50 mumol/L estradiol. Tryptophan on the other hand could block the progesterone (10 mumol/L) induced depolarization but had no effect on the db-cAMP induced hyperpolarization. The regulatory function of the amino acids and steroid hormones underlying oocyte maturation is discussed.
Wang
Y F
YF
Reproduction Endocrinology Laboratory of Harbin Medical University.
Cheng
J
J
Cheng
Z P
ZP
D000409:Alanine / Q000494:pharmacology; D000596:Amino Acids / Q000494:pharmacology*; D000818:Animals; D002023:Bufo bufo; D005260:Female; D007930:Leucine / Q000494:pharmacology; D008239:Lysine / Q000494:pharmacology; D008564:Membrane Potentials / Q000187:drug effects; D009865:Oocytes / Q000502:physiology*; D011374:Progesterone / Q000378:metabolism; D014364:Tryptophan / Q000494:pharmacology
D000596:Amino Acids; D011374:Progesterone; D014364:Tryptophan; D007930:Leucine; D008239:Lysine; D000409:Alanine