Disappearance of 1 α-3H-chlormadinone acetate from the plasma of women

Dugwekar, Y. G.; Narula, Ravinder; Laumas, K.R.

doi:10.1016/0010-7824(73)90004-8

Cited by 14 publications

(2 citation statements)

References 15 publications

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“…A high capacity of erythrocytes to concentrate and metabolize progesterone is known under in-vitro conditions (van der Molen & Groen, 1968), but its role in vivo is unclear. Unlike progesterone, synthetic progestogens are cleared slowly, possibly due to functional groups which delay the degradation of the steroids in the system and also because of their specific binding to plasma proteins (Dugwekar, Narula & Laumas, 1973;Murugesan & Laumas, 1975;Uniyal, Buckshee, Sharma & Laumas, 1976;Laumas, Farooq & Laumas, 1977). During pregnancy a sharp decline in the MCR of progesterone has been observed in guineapigs, caused by a rise in the amount of progesterone-binding protein in the peripheral plasma (Heap, 1969;Illingworth et al 1970).…”

Section: Discussionmentioning

confidence: 94%

Fate of Progesterone in the Plasma and Various Tissues of Anaesthetized Rabbits

Verma¹,

Laumas²

1981

Journal of Endocrinology

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Studies on the metabolism of progesterone in rabbit plasma and tissues during constant infusion of [3H]progesterone revealed a gradual increase in the concentration of progesterone in plasma until a state of equilibrium was attained about 2 h after the start of infusion. The metabolic clearance rate of progesterone was 0.116 l/min and the turn-over time was 0.006 min/ml plasma. Under conditions of equilibrium, the concentration of radioactivity as well as that of labelled progesterone was higher in the tissues than in plasma. On a unit-weight basis, myometrium localized 6.6 nCi, Fallopian tube 5.5 nCi and vagina 6.1 nCi [3H]progesterone/g tissue. A higher concentration of progesterone, 16.5 nCi, was localized in the mammary gland tissue. Skin localized only 0.9 nCi progesterone and the lowest amount (0.34 nCi/ml) was found in plasma. The metabolism of progesterone in tissues differed from that in plasma. In plasma only 5.6% of the infused steroid was recovered as unconverted progesterone and the major amount was metabolized to polar compounds with smaller amounts of 5 alpha-pregnane-3,20-dione, 5 alpha-pregnan-3 beta-ol-20-one and 20 alpha hydroxypregn-4-en-3-one. In the myometrium and Fallopian tubes the major metabolites were 5 alpha-pregnan-3 beta-ol-20-one and 5 alpha-pregnane-3,20-dione respectively. In the vagina, like the myometrium, 5 alpha-pregnan-3 beta-ol,20-one was the major metabolite. 20 alpha-Hydroxypregn-4-en-3-one was the major identified metabolite of mammary gland tissue.

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Section: Discussionmentioning

confidence: 94%

Fate of Progesterone in the Plasma and Various Tissues of Anaesthetized Rabbits

Verma¹,

Laumas²

1981

Journal of Endocrinology

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“…On the whole, norethrindrone has been reported to disappear slowly from the plasma, with metabolic clearance rates (MCR) of 351 I/day (12) and 600 l/day (15) which are much lower than the MCR of estradiol (1 350 I/day) (11) and progesterone (2443 I/day) (10). A low MCR has also been reported for norethindrone acetate (494 I/day) (17), norgestrel (458.5 I/day) (19) and chlormadinone acetate (126.6 I/day) (4). The lower MCR value of NET and NETA vis-A-vis natural steroids may also be a contributory factor for the accumulation of NET in the plasma of women in the present study.…”

Section: Discussionmentioning

confidence: 99%

Norethindrone in Serum After use of an oral Contraceptive Containing Norethindrone Acetate

Sarkar

Laumas

Agarwal

et al. 1983

Acta Obstet Gynecol Scand

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The availability of norethindrone (NET) in serum was studied in 8 women after daily administration of a combination oral contraceptive pill (MinovlarR) containing 1 mg norethindrone acetate (NETA) and 50 micrograms ethinyl estradiol (EE2) from day 5 to day 25 of the menstrual cycle. The pill was taken daily at 9:30 a.m. after a light breakfast and blood samples were collected at 3 hr on alternate days and at 24 hr on other days after ingestion of the pill. On day 12 or day 15 of the first treatment cycle, serial blood samples were also collected at 1/2, 1, 2, 4, 6, 8 and 24 hr after taking the pill. Serum NET levels were estimated by the radioimmunoassay (RIA) technique. The plot of serum NET concentration versus time (0-24 hr) profile showed a rapid absorption of steroid and a peak NET concentration (18.3 +/- 4.8 ng/ml) reached at 2 hr after ingestion of the pill. By linear regression analysis of data (y = 0.27 + 0.12x; r = 0.95), it was observed that the serum NET level was initially about 1 ng/ml. Thereafter, it increased by 0.12 ng/ml per day up to 3.5 ng/ml by the end of 21 days' treatment with oral pills. The serum NET concentration decay slope fitted a two-compartment open model with an initial rapid decay (half-life of 1.2 +/- 0.1 hr) followed by a slower beta-phase with a half-life of 8.5 +/- 1.5 hr. The study revealed that there was an accumulation of norethindrone in plasma during the treatment period and this suggests the possibility of exploring a reduction in the dose of this preparation so as to achieve the optimum NET concentration for contraception, and thereby avoiding unwanted steroid accumulation in the plasma of women.

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Steroidal Antiandrogens

Schröder¹,

Radlmaier²

2009

Hormone Therapy in Breast and Prostate Cancer

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Disappearance of 1 α-3H-chlormadinone acetate from the plasma of women

Cited by 14 publications

References 15 publications

Fate of Progesterone in the Plasma and Various Tissues of Anaesthetized Rabbits

Fate of Progesterone in the Plasma and Various Tissues of Anaesthetized Rabbits

Norethindrone in Serum After use of an oral Contraceptive Containing Norethindrone Acetate

Steroidal Antiandrogens

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