title: The effect of cyclical hormonal changes on erythrocyte electrolyte transport mechanisms.
abstract: Electrolyte transport characteristics were examined in erythrocytes from 13 normal men and from two groups of women: taking combined oral contraceptive preparations (O/C, n = 10), and ovulatory women (non-O/C, n = 10) pre- and post-ovulation, at the same time intervals (days 7-10 and days 15-18) during a menstrual cycle. With rubidium (86Rb+) used as a potassium analogue, co-transport (ouabain-resistant, frusemide-sensitive 86Rb+ influx) values were found to be lowest in non-O/C women (28 +/- SE 2.5 nmol h-1 10(-9) cells) and highest in men (56 +/- 5.7, P less than 0.001), with results between the two in women taking O/C (42 +/- 4.2, P less than 0.05 vs men, P less than 0.01 vs non-O/C). Passive 86Rb leak (frusemide-and ouabain-resistant) was significantly lower in men (13 +/- 1.6 nmol h-1 10(-9) cells) than in both groups of women (non-O/C 29 +/- 1.8, P less than 0.001; O/C 25 +/- 1.2, P less than 0.001). There was no cyclical variation within either group of women. Maximum ouabain binding (number of NA+,K+-ATPase units) was the same in all groups. Na+,K+-ATPase activity, as determined by ouabain-sensitive 86Rb influx, was the same in men and non-O/C groups, but was significantly suppressed in O/C compared with both men (P less than 0.01) and non-O/C women (P less than 0.05). The differences found were not due to alterations in either progesterone or aldosterone, but could represent an androgenic effect in vivo of the 19-nortestosterone derivatives in combined oral contraceptive preparations.
mesh_terms: D000328:Adult; D000450:Aldosterone / Q000378:metabolism; D001692:Biological Transport / Q000187:drug effects; D003277:Contraceptives, Oral, Combined / Q000494:pharmacology*; D004912:Erythrocytes / Q000378:metabolism*; D004997:Ethinyl Estradiol / Q000494:pharmacology; D005260:Female; D006801:Humans; D008297:Male; D008597:Menstrual Cycle; D009640:Norethindrone / Q000494:pharmacology; D011188:Potassium / Q000378:metabolism; D012083:Renin / Q000097:blood; D012964:Sodium / Q000378:metabolism; D000254:Sodium-Potassium-Exchanging ATPase / Q000378:metabolism
chemical_list: D003277:Contraceptives, Oral, Combined; D004997:Ethinyl Estradiol; D000450:Aldosterone; D012964:Sodium; D012083:Renin; D000254:Sodium-Potassium-Exchanging ATPase; D011188:Potassium; D009640:Norethindrone