Glomerular effects of AVT on the in situ perfused trunk preparation of the dogfish.

The effects of arginine vasotocin on the pattern of glomerular perfusion in an elasmobranch fish were examined using an in situ perfused renal trunk preparation. A significant antidiuresis was coupled with a marked reduction in the proportion of filtering glomeruli (86%-25%) and an increase in the proportion of perfused but not filtering (10%-53%) and non-perfused glomeruli (4%-22%). However, the reduction in filtering glomeruli was greater than predicted by measurements of urine flow rate and glomerular filtration rate alone, suggesting that alterations in single nephron glomerular filtration rate may occur.