The effect of human chorionic gonadotropin on methotrexate concentration in the rat testes.
OBJECTIVE
We analyzed the effect of human chorionic gonadotropin (hCG) on drug concentrations in testicular interstitial fluid and whole testis tissue samples in rats receiving hCG prior to methotrexate (MTX) administration and in animals that did not receive hCG.


METHODS
Adult male Sprague-Dawley rats were injected subcutaneously with 200 i.u. hCG (Goldline Laboratories, Ft. Lauderdale, FL.). Controls were injected subcutaneously with normal saline (0.2 cc). Sixteen hours after injection, each rat was given methotrexate (Methotrexate LPF, Immunex Corp. Seattle WA.) via a carotid artery cannula in a dose of 30 mg./kg. Methotrexate (MTX) levels were collected 60 minutes post infusion time in 27 rats and 90 minutes post infusion in 27 rats. MTX levels were measured in serum, testicular interstitial fluid and testicular tissue. MTX levels were measured using high performance liquid chromatography (HPLC).


RESULTS
A significantly higher concentration of MTX was found in testicular interstitial fluid (TIF) in rats injected with hCG when specimens were collected 60 minutes post infusion. MTX levels in TIF had reversed 90 minutes post infusion with higher levels found in control rats. Tissue levels of MTX demonstrated no significant difference at either 60 or 90 minutes in the hCG treated animals or controls.


CONCLUSIONS
Our results suggest that hCG effects the tissue distribution of MTX within the testis. Human chorionic gonadotropin may have this effect on the testicular microvasculature by 1) selectively increasing capillary permeability, 2) increasing lymphatic flow within the testes or 3) increasing testicular blood flow.
Bettencourt
M C
MC
Department of Surgery, and Military Andrology Research Center, Walter Reed Army Medical Center, Washington, DC 20306-5001, USA.
Morris
E R
ER
Spevak
M
M
Costabile
R
R
D000818:Animals; D006063:Chorionic Gonadotropin / Q000502:physiology*; D006801:Humans; D008297:Male; D008727:Methotrexate / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D013737:Testis / Q000378:metabolism*
D006063:Chorionic Gonadotropin; D008727:Methotrexate