This study showed that ovarian inhibin A and B were cleared from the circulation within 12 h of oophorectomy, whereas E(2) and progesterone remain in the circulation for longer. Negative correlation between FSH, inhibin A and inhibin B suggests that inhibins may contribute to the observed early rise in FSH after the surgical menopause.

Serum paraoxonase is known to prevent low-density lipoprotein oxidation and atherogenesis. Association of paraoxonase with the oxidative status and lipid profile in chronic renal failure (CRF) patients on conservative management and those on chronic maintenance hemodialysis was analyzed in the present study. Serum paraoxonase, protein thiols, lipid hydroperoxides, lipid profile, creatinine and albumin levels were estimated by spectrophotometric methods in CRF patients on conservative management, those on hemodialysis and in healthy controls. Total cholesterol, triglycerides, low-density lipoprotein cholesterol, lipid hydroperoxides and creatinine levels were higher and high-density lipoprotein cholesterol, protein thiols, albumin levels and paraoxonase activity were lower in patients than in healthy controls. Paraoxonase activity correlated positively with protein thiols and high-density lipoprotein cholesterol and negatively with low-density lipoprotein cholesterol and lipid hydroperoxides. In conclusion, paraoxonase activity is decreased in CRF patients particularly on chronic maintenance hemodialysis and correlates well with the oxidative stress markers.

Objective: Inhibin, activin and follistatin are glycoprotein hormones produced by the gonads. Recent studies have shown that inhibin B is the predominant form of inhibin in the circulation in men. The objective of this study was to investigate circulating levels of activin A and follistatin in disorders of spermatogenesis in men and their relationship with FSH and inhibin B. Design and method: Serum from five different groups of men was prospectively collected and stored at 220 8C. The groups were men with: (i) proven fertility (controls) n 20, (ii) primary testicular failure n 15, (iii) obstructive azoospermia n 10, (iv) oligospermia n 10 and (v) miscellaneous sperm dysfunction n 40. WHO criteria (1992) were used for semen characterisation. Serum concentrations of`total' activin A, follistatin, FSH and inhibin B were measured using specific two-site enzyme immunoassays. Results: Activin A levels were significantly lower than in the controls in the obstructive azoospermia group and higher in the miscellaneous sperm dysfunction group. Serum follistatin levels did not significantly vary in any group compared with the controls. Circulating levels of FSH were higher than in the controls in the primary testicular failure and obstructive azoospermic group. Levels of inhibin B were lower than in the controls in all disorders of spermatogenesis studied. Conclusion: This study demonstrates that activin A and follistatin are in the circulation in males and activin A levels are significantly lower in obstructive azoospermia and higher in miscellaneous sperm dysfunction than in controls. The mechanism involved in altering the levels of activin A in these conditions is not clear. However, high follistatin:activin A molar ratios (.2.5) in all groups suggests that all activin A in the circulation is bound to follistatin in males.

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