EPISODIC CHANGES OF SERUM PROCOLLAGEN TYPE-I CARBOXY-TERMINAL PROPEPTIDE LEVELS IN FERTILE AND POSTMENOPAUSAL WOMEN

The aim of the present study was to optimize the use of serum procolla gen type I carboxy-terminal propeptide (PICP) as a possible marker of postmenopausal-3761ted changes of bone metabolism. Postmenopausal (n = 20) and healthy fertile young (n = 4) women were studied after inform ed consent. The postmenopausal women were subdivided in 4 groups: (1) nontreated; (2) treated with estrogen-progestogen replacement therapy; (3) treated with calcitonin, or (4) with kidney or liver diseases. Bl ood samples were collected at 15-min time intervals for 4, 6 or 8 h. S erum concentration of PICP was measured by radioimmunoassay, in duplic ate at two different dilutions. In postmenopausal women mean +/- SEM s erum PICP levels were slightly but nonsignificantly higher than in fer tile women. Serum PICP levels in estrogen-progestogen or calcitonin-tr eated women were significantly lower than in non-treated postmenopausa l women. Episodic changes of circulating PICP level were observed in f ertile and postmenopausal women. The pulses of serum PICP levels did n ot show significant differences among the groups of women studied. The present study showed that the measurement of serum PICP levels is a u seful marker for investigating the changes of bone metabolism. In part icular, low PICP levels in postmenopausal women under steroid hormone or calcitonin treatment in part reflect the changes of bone turnover. The pulses of serum PICP levels during a time interval suggest that co llagen metabolism in women undergoes a rapid turnover.