RE: Modeling Growth Hormone Pulsatility

Dear Jian, We have good experience of a surge function. Surges, characterised by the parameters SA (surge amplitude), SW (surge width), T (clock time) and Pt (peak time), were used to define the function g(clock time) according to Eq. 4. g(Clock time) = SA / (((T - Pt) / SW)4 + 1) (Eq.4) This was presented by Nelamangala et al below (applied to LH surges). We applied it to ACTH / Cortisol. It was superior to (sum of) cosine functions for these hormones. Best regards, Mats Nelamangala N, Pechstein B, Erb K, Klipping C, Hermann R, Locher M, Derendorf H. Pharmacokinetic/Pharmacodynamic modeling of luteinizing hormone (LH) suppression and LH surge delay by Cetrorelix after single and multiple doses in healthy postmenopausal women. J Clin Pharmacol 2003; 43:243-251. Lonnebo A, Grahnen A, Karlsson MO. An integrated model for the effect of budesonide on ACTH and cortisol in healthy volunteers. Br J Clin Pharmacol. 2007 Feb 28; [Epub ahead of print] Mats Karlsson, PhD Professor of Pharmacometrics Div. of Pharmacokinetics and Drug Therapy Dept. of Pharmaceutical Biosciences Faculty of Pharmacy Uppsala University Box 591 SE-751 24 Uppsala Sweden phone +46 18 471 4105 fax +46 18 471 4003 [EMAIL PROTECTED] _____