Liquid chromatographic assay with ultraviolet detection for the study of microsomal steroid metabolism

Bioequivalence of progesterone sustained release suppository in rabbits

To study the bioequivalence of a kind of progesterone sustained release suppository, a randomized cross-over study was conducted in 12 rabbits. A single rectal dose of 2.75 mg/kg progesterone sustained released suppository (tested formulation, T) and progesterone suppository (reference formulation, R) was administered; a multiple dose of 2.75 mg/kg was given up to seven times with an interval of 8 h. Concentrations in serum were determined by a competitive enzyme immunoassay. The main parameters of T were: for single and multiple doses, Cmax was 48.8 +/- 11.8 ng/mL and 43.5 +/- 9.4 ng/mL, Tmax was 0.5 +/- 0.3 h and 0.4 +/- 0.3 h, AUC(0-24 h) was 362.4 +/- 143 ng x h x mL(-1) and 310.6 +/- 70.3 ng x h x mL(-1), respectively. The relative bioavailability of T to R were (104.2 +/- 13.4)% and (111.4 +/- 19.1)%, respectively. Statistical analysis showed that the two formulations were bioequivalent and T had sustained released feature.

High-performance liquid chromatographic analysis of corticosteroids

This review presents recent developments in high-performance liquid chromatographic (HPLC) analysis of corticosteroids for the determination of clinically important steroids in biological specimens. Various sample preparation techniques are described.

The effects of an interferon inducer, polyriboinosinic polyribocytidylic acid on cytochrome P-450 dependent hepatic progesterone metabolism

A time course study on the effects of an interferon inducing agent, polyriboinosinic polyribocytidylic acid (poly rIrC) on the hepatic cytochrome P-450 dependent progesterone metabolism was performed. Administration of a single dose of poly rIrC (10 mg/kg i.p.) to adult male Wistar rats caused a time dependent effect on liver weight, microsomal protein and total cytochrome P-450 levels, as well as the 16 alpha and 6 beta hydroxylation of progesterone. The response was multiphasic, with a maximal depression of both hydroxylase activity 48 hours post-injection, followed by enhanced activity at 72 hours and subsequent return to control activity twenty-four hours later. A second less dramatic rise in the activities followed, bringing the 16 alpha and 6 beta hydroxylase activity to 159% and 141% of their respective control values by 336 hours, at which point of time, the trend appeared to be still on the rise. The enhanced activity at 72 hours was preceded by an increase in serum cortisol and corticosterone levels, the ability of which to enhance the activity of 6 beta hydroxylation of steroids may partly explain the phenomenon.

Ontogenic development of liver progesterone metabolism in female sheep. Contribution of cytochrome P4502B and P4503A subfamilies

Age-related changes in progesterone hepatic metabolism were measured in Lacaune ewes in the foetal, neonatal (1 and 4 weeks), growing (7 months), pregnant (11 months) and adult (6 years) stages. 6 beta-Hydroxylation and 20 alpha-reduction were found to be the most efficient metabolic process in ovine microsomes. These activities were detected in 3-month-old foetuses and they increased rapidly during the first month of life, in a similar manner to the developmental expression of the cytochrome P4503A subfamily. 16 alpha- and 21-hydroxylation of progesterone were characterized by low, constant turn over in sheep liver microsomes during development. The hepatic ovine P4502B isozyme was purified to electrophoretic homogeneity by means of successive DEAE cellulose, hydroxylapatite and CM cellulose chromatographic separations. This hemoprotein had an apparent molecular weight of 51 kDa and was characterized by spectral data, NH2-terminal amino-acid sequence, immunological and catalytic properties. The relative contribution of this form and of the previously purified ovine P4503A subfamily was investigated in liver progesterone metabolism by immunoinhibition studies using polyclonal antibodies raised in rabbits and from the existence of induction and of significant correlations between microsomal activity and specific P450 content. In sheep liver microsomes, it would appear that cytochrome P4502B is involved in progesterone 21-hydroxylation whereas P4503A participates in the 6 beta- and 16 alpha-hydroxylation and possibly in the reductive conversion of progesterone in its 20 alpha-hydroxy derivative.