Impermeability of the rat blood-brain barrier to exogenously administered gonadotropin-releasing hormone.
To assess the permeability of the blood-brain barrier (BBB) to exogenously administered gondatrophin-releasing hormone (GnRH), a study was performed in male-rats using the double isotope, intracarotid, single injection technique of Oldendorf. The mean (+/- SEM) brain uptake indices (BUI) of 3H-GnRH in comparison to a freely diffusible reference compound, 14C-butanol, were 1.1 +/- 0.2, 3.5 +/- 0.7 and 3.0 +/- 0.6 when the injection vehicles were Ringer's lactate, rat serum and human serum, respectively. The BUI of 3H-GnRH was similar to that of 3H-inulin, a nondiffusible compound. With different concentrations, the BUI of 3H-GnRH did not change significantly. These data indicate that the BBB of the male rat is impermeable to exogenously administered GnRH.
D000818:Animals; D001692:Biological Transport; D001812:Blood-Brain Barrier; D001921:Brain / Q000378:metabolism; D002199:Capillary Permeability; D008297:Male; D010906:Pituitary Hormone-Releasing Hormones / Q000378:metabolism; D051381:Rats / Q000502:physiology*; D011919:Rats, Inbred Strains
D010906:Pituitary Hormone-Releasing Hormones